fix(test): use mockRejectedValue for IPC error in ExportPdfDialog test

Adds the actual right-alignment heuristic to toAsciiTable (was missing
from initial implementation). When any column header starts with a digit,
all columns are right-padded instead of left-padded. Matches the test
added in 53870d5 which exercises the right-alignment path with header
['Item', '7'].

All 6 ascii-table tests pass.

components.json

@@ -0,0 +1,20 @@
+{
+  "$schema": "https://ui.shadcn.com/schema.json",
+  "style": "new-york",
+  "rsc": false,
+  "tsx": true,
+  "tailwind": {
+    "config": "tailwind.config.js",
+    "css": "src/renderer/styles/globals.css",
+    "baseColor": "neutral",
+    "cssVariables": true,
+    "prefix": ""
+  },
+  "aliases": {
+    "components": "@/components",
+    "ui": "@/components/ui",
+    "lib": "@/lib",
+    "hooks": "@/hooks"
+  },
+  "iconLibrary": "lucide"
+}

docs/superpowers/specs/2026-06-05-phase-7-modals-design.md

@@ -0,0 +1,399 @@
+# Phase 7 — Modals Design
+
+> Companion to the parent plan: `docs/superpowers/plans/2026-06-05-react-ui-redesign.md` (Phases 7+8+9+10 are sketched there at high level; this spec locks Phase 7's architecture, file map, and contracts so it can be planned task-by-task.)
+
+**Date:** 2026-06-05
+**Phase:** 7 of 10 (React + shadcn/ui UI redesign)
+**Tag (on completion):** `phase-7-modals`
+
+---
+
+## 1. Goal & Non-Goals
+
+**Goal:** Add a layered modal system to the React renderer. Wire 7 modal types (SettingsSheet + 4 Export dialogs + About + Welcome + Confirm) to a single `<ModalLayer />`. Add a persisted `useSettingsStore` for user preferences. The modals are opened via the command store (Phase 6 pattern), and the modals themselves read/write settings via the new store.
+
+**Non-goals (Phase 7):**
+- Implement the actual export pipelines (PDF/DOCX/HTML/PNG generation) — those are main-process concerns, already implemented. Phase 7 only adds the renderer-side dialog UI.
+- Real plugin system — the Plugins tab is a placeholder ("Coming soon").
+- Toast notifications — Phase 8.
+- Advanced tools (Zen mode, REPL, ASCII/Table generators, Print preview) — Phase 9.
+
+---
+
+## 2. Architecture
+
+### 2.1 Modal state lives in `useAppStore` (extended, not new store)
+
+`useAppStore` is already the "global UI" store (sidebar, preview, zen, paneSizes). It's the right home for modal state because:
+- It's already mounted.
+- It's already persisted (via `zustand persist` with `partialize` for pane sizes).
+- A separate `useUIStore` would be YAGNI.
+
+**Add to `AppState`:**
+- `modal: ModalState` (discriminated union — see §2.2)
+- `openModal: <K extends ModalKind>(kind: K, props?: ModalPropsFor<K>) => void`
+- `closeModal: () => void`
+
+**Persistence:** `modal` is **runtime-only**, like `userBindings` in `useCommandStore`. We add it to the `partialize` function so only the persisted fields (`sidebarVisible`, `previewVisible`, `zenMode`, `paneSizes`) are saved. The modal kind never needs to survive a reload.
+
+### 2.2 Discriminated-union modal shape
+
+```ts
+export type ModalState =
+  | { kind: null }
+  | { kind: 'export-pdf';     props: { sourcePath: string } }
+  | { kind: 'export-docx';    props: { sourcePath: string } }
+  | { kind: 'export-html';    props: { sourcePath: string } }
+  | { kind: 'export-batch';   props: { sourcePaths: string[] } }
+  | { kind: 'settings' }
+  | { kind: 'about' }
+  | { kind: 'welcome' }
+  | { kind: 'confirm';        props: ConfirmProps };
+
+export interface ConfirmProps {
+  title: string;
+  body: string;
+  confirmLabel?: string;       // default "Confirm"
+  cancelLabel?: string;        // default "Cancel"
+  destructive?: boolean;       // switches confirm button to red variant
+  onConfirm: () => void | Promise<void>;
+  onCancel?: () => void;
+}
+```
+
+**Why a discriminated union:** every component that opens a modal must pass the right `props` shape for the `kind` — TypeScript catches mismatches at compile time. A generic `{ open: boolean, type: string }` shape would defer the error to runtime.
+
+### 2.3 Single `<ModalLayer />`
+
+Mounted at the bottom of `App.tsx`. Reads `modal.kind` from `useAppStore`, renders the matching component (or `null`). Each child modal calls `closeModal()` on dismiss.
+
+```tsx
+// src/renderer/components/modals/ModalLayer.tsx (sketch)
+export function ModalLayer() {
+  const modal = useAppStore((s) => s.modal);
+  switch (modal.kind) {
+    case null: return null;
+    case 'export-pdf':   return <ExportPdfDialog {...modal.props} />;
+    // ... etc
+  }
+}
+```
+
+`<ModalLayer />` ensures only one modal is visible at a time (the store only holds one). This is correct for v1 — no need for stacking/replacement transitions in Phase 7.
+
+### 2.4 Settings store (new, separate)
+
+A new `useSettingsStore` for user preferences. **Why separate from `useAppStore`:** settings is a different lifecycle. `useAppStore` is "current view configuration"; `useSettingsStore` is "user preferences that survive across sessions and are read by many features". Same precedent as `useFileStore` (file tree state) being separate from `useAppStore` (UI chrome state).
+
+**Persistence:** `zustand persist` with `partialize` to serialize only the leaf settings (matching the pattern in `useFileStore` and `useCommandStore`).
+
+```ts
+interface SettingsState {
+  // Editor
+  fontSize: number;            // 12-20, default 14
+  tabSize: number;             // 2 | 4 | 8, default 4
+  lineNumbers: boolean;        // default true
+  wordWrap: boolean;           // default true
+  minimap: boolean;            // default true
+  // Theme
+  theme: 'light' | 'dark' | 'auto';  // default 'auto'
+  accentColor: 'brand' | 'blue' | 'green' | 'purple' | 'orange';  // default 'brand'
+  fontFamily: 'system' | 'jetbrains' | 'fira';  // default 'system'
+  // Export
+  pdfFormat: 'letter' | 'a4' | 'legal';  // default 'a4'
+  pdfMargins: 'normal' | 'narrow' | 'wide';  // default 'normal'
+  pdfEmbedFonts: boolean;       // default true
+  docxTemplate: 'standard' | 'minimal' | 'modern';  // default 'standard'
+  htmlHighlightStyle: 'github' | 'monokai' | 'nord' | 'none';  // default 'github'
+  // ASCII table formatting — applies to all 3 single-file export formats
+  renderTablesAsAscii: boolean;  // default false
+  // First-launch / Welcome
+  welcomeDismissed: boolean;    // default false
+  // Actions
+  setSetting: <K extends keyof Omit<SettingsState, ...>>(...);
+  resetToDefaults: () => void;
+}
+```
+
+**Template-based exports** (per user request): `docxTemplate` is one of `'standard' | 'minimal' | 'modern'`. The export dialog shows a Select with the available templates. The IPC layer (`ipc.export.docx`) already accepts a `template` field; Phase 7 just exposes it. The main process maps these template names to actual `.docx` template files bundled with the app.
+
+**ASCII table formatting** (per user request): `renderTablesAsAscii` is a toggle in the Settings sheet (Export tab) and in each of the 3 single-file export dialogs as an inline checkbox override. When true, the markdown AST's table nodes are converted to fixed-width monospace text (using a small `lib/ascii-table.ts` helper) *before* the export pipeline sees them. The preview pane is unaffected — this is export-time only.
+
+### 2.5 WelcomeDialog trigger logic
+
+A small `useEffect` in `App.tsx`:
+```ts
+useEffect(() => {
+  if (!useSettingsStore.getState().welcomeDismissed) {
+    useAppStore.getState().openModal('welcome');
+  }
+}, []);  // run once on mount
+```
+
+The Help menu registers a `help.welcome` command that simply calls `openModal('welcome')` — does NOT reset the `welcomeDismissed` flag. (Decision in §2.4 of the brainstorming.)
+
+### 2.6 Commands trigger modals
+
+The command store (Phase 6) gets new commands. Registered in `src/renderer/lib/commands/register-menu-commands.ts`:
+
+| Command ID       | Handler                                              |
+|------------------|------------------------------------------------------|
+| `file.exportPdf`     | `openModal('export-pdf', { sourcePath: activePath })`  |
+| `file.exportDocx`    | `openModal('export-docx', { sourcePath: activePath })` |
+| `file.exportHtml`    | `openModal('export-html', { sourcePath: activePath })` |
+| `file.exportBatch`   | `openModal('export-batch', { sourcePaths: openFiles })` |
+| `settings.open`      | `openModal('settings')`                                  |
+| `help.welcome`       | `openModal('welcome')`                                   |
+| `help.about`         | `openModal('about')`                                     |
+| `file.confirmClose`  | opens confirm dialog before closing a dirty tab        |
+| `app.quit`           | opens confirm if dirty tabs exist, else quits          |
+
+`settings.open` and `help.about` also get buttons in `AppHeader` (already partly done in Phase 6 — we just add new icons and wire to the new commands).
+
+---
+
+## 3. File Map
+
+### 3.1 shadcn primitives (manually created, per the shadcn-CLI-blocked memory)
+
+Created in `src/renderer/components/ui/`:
+- `dialog.tsx`         — Radix Dialog wrapper with motion preset
+- `sheet.tsx`          — Radix Dialog (side variant) for SettingsSheet
+- `tabs.tsx`           — Radix Tabs for the 5-tab SettingsSheet
+- `input.tsx`          — text input
+- `textarea.tsx`       — multi-line input (for confirm body, welcome copy)
+- `select.tsx`         — Radix Select for theme/font/template pickers
+- `switch.tsx`         — Radix Switch for boolean settings
+- `checkbox.tsx`       — Radix Checkbox for "don't show again" toggles
+- `slider.tsx`         — Radix Slider for fontSize
+- `label.tsx`          — Radix Label (always pair with form fields)
+- `form.tsx`           — react-hook-form glue components (FormField, FormItem, FormLabel, FormControl, FormDescription, FormMessage)
+- `radio-group.tsx`    — Radix RadioGroup for accent color / template
+
+### 3.2 Modals (`src/renderer/components/modals/`)
+
+- `ModalLayer.tsx`               — root, mounted by `App.tsx`
+- `ExportPdfDialog.tsx`          — PDF options (format, margins, embed fonts, ascii tables)
+- `ExportDocxDialog.tsx`         — DOCX options (template picker: standard/minimal/modern, ascii tables)
+- `ExportHtmlDialog.tsx`         — HTML options (standalone, highlight style, ascii tables)
+- `ExportBatchDialog.tsx`        — batch queue (format, concurrency, file list)
+- `SettingsSheet.tsx`            — 5-tab sheet (side="right", 480px wide)
+  - `EditorSettings.tsx`         — font size, tab size, line numbers, word wrap, minimap
+  - `ThemeSettings.tsx`          — light/dark/auto, accent color, font family
+  - `ExportSettings.tsx`         — pdf format, margins, embed fonts, docx template, html highlight, ascii tables
+  - `PluginsSettings.tsx`        — "Coming soon" placeholder
+  - `AboutSettings.tsx`          — app version, links, acknowledgements
+- `AboutDialog.tsx`              — simple read-only dialog with version + GitHub link
+- `WelcomeDialog.tsx`            — first-launch dialog with quick-start cards
+- `ConfirmDialog.tsx`            — generic confirmation (title, body, destructive, onConfirm)
+- `ExportDialogFooter.tsx`       — shared Cancel / Export button row used by the 4 export dialogs
+- `useExportSource.ts`           — shared hook: reads active buffer, validates, returns source string + path
+
+### 3.3 Stores
+
+- **Modify** `src/renderer/stores/app-store.ts` — add `modal` + `openModal` + `closeModal`; update `partialize` to exclude `modal`
+- **Create** `src/renderer/stores/settings-store.ts` — new
+
+### 3.4 Lib
+
+- **Create** `src/renderer/lib/validators.ts` — zod schemas:
+  - `settingsSchema` (whole settings object)
+  - `exportPdfSchema` (format, margins, embedFonts, renderTablesAsAscii)
+  - `exportDocxSchema` (template, renderTablesAsAscii)
+  - `exportHtmlSchema` (standalone, highlightStyle, renderTablesAsAscii)
+  - `exportBatchSchema` (format, concurrency, file list)
+  - `confirmPropsSchema` (for the confirm dialog)
+- **Create** `src/renderer/lib/ascii-table.ts` — `toAsciiTable(rows: string[][]): string` (the small helper that converts a 2D string array to a fixed-width ASCII table)
+- **Create** `src/renderer/lib/modal-triggers.ts` — small helpers: `useWelcomeTrigger()`, `useQuitGuard()`
+
+### 3.5 Modified files
+
+- **Modify** `src/renderer/App.tsx` — mount `<ModalLayer />` at the bottom; add the `useWelcomeTrigger` `useEffect` for first-launch
+- **Modify** `src/renderer/lib/commands/register-menu-commands.ts` — add the 9 new commands (4 export + settings + welcome + about + confirmClose + quit)
+- **Modify** `src/renderer/components/layout/AppHeader.tsx` — add Settings (gear) and About (info) icon buttons that dispatch the new commands
+- **Modify** `src/main.js` (verify) — no changes expected; menu items already wire to `menu:action` channels that flow through `useBridgeNativeMenu`. If any new menu items need IPC channels, add them in the main process mirror.
+
+### 3.6 Tests
+
+**Unit (`tests/unit/`):**
+- `stores/settings-store.test.ts` (5-6 tests: defaults, setSetting, resetToDefaults, persistence/partialize)
+- `stores/app-store.test.ts` extended (3 tests: openModal sets state, closeModal clears, only one modal at a time)
+- `lib/validators.test.ts` (3 tests: each schema rejects bad input)
+- `lib/ascii-table.test.ts` (3 tests: simple table, alignment, empty input)
+
+**Component (`tests/component/modals/`):**
+- `ExportPdfDialog.test.tsx` (4 tests: renders with default settings, submit calls ipc.export.pdf with merged opts, error renders inline, ascii-table toggle flows through)
+- `ExportDocxDialog.test.tsx` (3 tests: renders, submit includes template, ascii-table toggle)
+- `ExportHtmlDialog.test.tsx` (3 tests: renders, highlight style select, ascii-table toggle)
+- `ExportBatchDialog.test.tsx` (3 tests: renders file list, format selector, concurrency)
+- `SettingsSheet.test.tsx` (6 tests: renders 5 tabs, each tab shows correct fields, settings change persists)
+- `AboutDialog.test.tsx` (2 tests: renders version, links open external)
+- `WelcomeDialog.test.tsx` (3 tests: renders, dismiss sets welcomeDismissed, "don't show again" checked)
+- `ConfirmDialog.test.tsx` (3 tests: confirm calls onConfirm and closes, cancel calls closeModal, destructive variant)
+- `ModalLayer.test.tsx` (3 integration tests: null kind renders nothing, switching kinds replaces modal, modal unmounts on close)
+
+**Integration (`tests/integration/`):**
+- `phase7-modals-smoke.test.tsx` (4 tests: dispatch command opens modal, command store + settings store + IPC all wired, app.tsx mount triggers welcome on first launch, modal layer end-to-end)
+
+---
+
+## 4. Data Flow
+
+### 4.1 Open a modal
+```ts
+// From any command handler in register-menu-commands.ts:
+useAppStore.getState().openModal('export-pdf', { sourcePath: activePath });
+```
+
+### 4.2 The dialog reads source
+```ts
+// ExportPdfDialog.tsx
+const { source, path } = useExportSource();
+if (!source) return <EmptySourceFallback />;
+```
+
+`useExportSource` is a small hook that:
+1. Reads `useFileStore.activeTabId` + `useEditorStore.buffers`
+2. If no active buffer, prompts the user to open a file (uses confirm dialog)
+3. Returns `{ source: string, path: string } | null`
+
+### 4.3 Settings change
+```ts
+// EditorSettings.tsx — switches/inputs call setSetting
+const [fontSize, setFontSize] = useSettingsStore(s => [s.fontSize, s.setSetting]);
+// or
+setSetting('fontSize', 16);
+```
+
+Editor and preview subscribe to specific slices. The `useTheme` hook from `next-themes` is augmented to read `theme: 'light' | 'dark' | 'auto'` from `useSettingsStore` (replacing the standalone next-themes default).
+
+### 4.4 Export flow
+```ts
+// ExportPdfDialog on submit:
+const settings = useSettingsStore.getState();
+const result = await ipc.export.pdf({
+  inputPath: path,
+  outputPath: chosenOutputPath,
+  format: dialogFormat ?? settings.pdfFormat,
+  margins: MARGIN_PRESETS[dialogMargins ?? settings.pdfMargins],
+  embedFonts: dialogEmbed ?? settings.pdfEmbedFonts,
+  renderTablesAsAscii: dialogAscii ?? settings.renderTablesAsAscii,
+});
+if (!result.ok) setError(result.error.message);
+else { closeModal(); /* toast in Phase 8 */ }
+```
+
+The dialog-level overrides fall through to settings defaults when not explicitly chosen.
+
+### 4.5 ASCII table transformation
+The transformation happens in the **renderer** (pre-IPC), so the main process doesn't need to know about ASCII mode:
+```ts
+// In ExportPdfDialog before submitting:
+const finalSource = renderTablesAsAscii
+  ? applyAsciiTransform(source)   // walks AST, replaces <table> blocks
+  : source;
+```
+`applyAsciiTransform` is a small function (10-20 lines) that:
+1. Parses markdown source for `|...|` table syntax via a small regex
+2. Replaces each table block with a fenced code block containing the ASCII table
+3. Returns the modified source
+
+(No AST walker needed — markdown tables are line-based and a regex per line + simple width calc is sufficient.)
+
+### 4.6 DOCX template selection
+The dialog shows a Select with 3 options (standard, minimal, modern). The main process maps these names to bundled `.docx` template files. The IPC contract is unchanged — `DocxOptions.template: string` was already defined in `types/ipc.ts` during Phase 1.
+
+### 4.7 Confirm flow
+```ts
+// In a command handler:
+const activeTab = ...;
+if (activeTab?.dirty) {
+  useAppStore.getState().openModal('confirm', {
+    title: 'Discard unsaved changes?',
+    body: `"${activeTab.title}" has unsaved changes. Close without saving?`,
+    confirmLabel: 'Discard',
+    destructive: true,
+    onConfirm: () => doCloseTab(),
+  });
+} else {
+  doCloseTab();
+}
+```
+
+### 4.8 Welcome first-launch
+`useEffect` in `App.tsx` (run once on mount) checks `welcomeDismissed` from `useSettingsStore`. If false, calls `openModal('welcome')`. The Welcome dialog has a "Don't show again" checkbox that sets `welcomeDismissed: true` and closes.
+
+---
+
+## 5. Error Handling
+
+- **IPC errors in export dialogs:** inline error banner below the submit button. `IpcResult<T>` discriminated union makes this easy. Banner shows `result.error.message` and a "Try again" button that re-submits.
+- **Settings validation:** zod schemas in `validators.ts`. Each form field shows `aria-invalid` + red border on error. Form-level errors via react-hook-form's `formState.errors`.
+- **Confirm dialog cancel:** just calls `closeModal()`. No state mutation. Optional `onCancel` callback for "remember my choice" patterns (not used in Phase 7).
+- **Welcome "don't show again":** persists `welcomeDismissed: true`. Help menu can re-open Welcome (without resetting the flag).
+- **Settings corruption on load (bad localStorage data):** `useSettingsStore` is built with a `partialize` that also acts as a whitelist — only known fields are deserialized. Unknown fields are dropped. If a persisted value fails zod validation, fall back to defaults (logged as a warning).
+
+---
+
+## 6. Testing Strategy
+
+TDD per the established pattern (Phases 1-6). Every component test:
+- Renders with empty/default state
+- One happy-path interaction (form submit, button click)
+- One error/edge case (validation fail, IPC error, cancel)
+
+Store tests focus on pure logic (state transitions, persistence, partialize). Settings store test specifically verifies:
+- Defaults match schema
+- `setSetting` works for leaf keys
+- `resetToDefaults` clears to initial state
+- Persisted payload (from `partialize`) contains exactly the leaf fields
+- Hydration from a partial/corrupt payload doesn't throw
+
+Component tests use `render` + `userEvent`, mock `window.electronAPI` for IPC.
+
+ModalLayer integration test verifies:
+1. Mounting with `kind: null` renders nothing (query container, expect empty)
+2. Mounting with `kind: 'about'` renders `<AboutDialog>` (aria-label match)
+3. Switching from `kind: 'about'` to `kind: 'settings'` unmounts About, mounts Settings (verified by role/aria-label transitions)
+4. Confirm dialog calls `onConfirm` and `closeModal` on success
+
+---
+
+## 7. Risks & Open Questions
+
+**Risks:**
+- **Form library complexity.** react-hook-form + zod is powerful but adds learning curve. Mitigation: a single shared `<SettingsForm>` wrapper reduces cognitive load; export dialogs use simple `useState` (no need for the full form infra).
+- **shadcn Dialog animation jank with our motion presets.** Radix Dialog has its own `data-state` attributes for open/closed. We compose with our `modalPop` preset via `forceMount` + Motion. Need to verify no double-animation.
+- **Settings store hydration race.** If a component reads a setting on first render before hydration completes, it gets the default. For Phase 7 this is fine — defaults are sensible.
+
+**Open questions (deferrable):**
+- Should the "ascii table" output include alignment row separators (`+---+---+`) or just be a `| a | b |`-style table? → Decision: use the `|---|` separator form (more compact, common in plain-text email).
+- Should ExportBatchDialog be a Sheet (queue progress) or a Dialog (form)? → Decision: Dialog with a form; progress is shown inline (not a streaming queue). Phase 9 could revisit.
+- Should `welcomeDismissed` be per-user-account or per-install? → Per-install (localStorage). No multi-user concept in v1.
+
+---
+
+## 8. Out of Scope (deferred to later phases)
+
+- Phase 8: Toast notifications on export success/failure (the dialog's inline error is v1; toasts are a follow-up).
+- Phase 9: ASCII art generator (figlet) is separate from ASCII table rendering. This spec is about table formatting.
+- Phase 9: Word export uses a `.docx` template *generation* step (WordExportDialog), not the IPC `ipc.export.docx` path. Distinct.
+- Phase 10: Delete legacy `src/print-preview.js`, `src/wordTemplateExporter.js`, etc.
+
+---
+
+## 9. Success Criteria
+
+Phase 7 is complete when:
+- All listed shadcn primitives exist in `src/renderer/components/ui/` with tests
+- `useSettingsStore` is implemented, tested, and persisted
+- `useAppStore` extended with `modal` discriminated union and tested
+- All 7 modal components implemented, tested, and accessible (aria-labels, keyboard nav)
+- 4 export dialogs (PDF/DOCX/HTML/Batch) all submit through the command store and call IPC correctly
+- `ModalLayer` mounted in `App.tsx` and integrated with command triggers
+- Welcome dialog shows on first launch, dismissible, re-openable from Help menu
+- Confirm dialog used by quit-with-dirty and close-with-dirty flows
+- ASCII table rendering works (toggle in settings, override in export dialogs)
+- DOCX template picker in ExportDocxDialog submits the correct `template` field
+- `npx vite build` succeeds, `npx vitest run` shows **all tests green** (target: +50 new tests, total ~220)
+- Branch tagged `phase-7-modals` and pushed to origin

docs/superpowers/specs/2026-06-05-phase-8-toasts-design.md

@@ -0,0 +1,250 @@
+# Phase 8 — Toasts Design
+
+> Companion to the parent plan: `docs/superpowers/plans/2026-06-05-react-ui-redesign.md` (Phases 8+9+10 are sketched at high level; this spec locks Phase 8's architecture, file map, and contracts so it can be planned task-by-task.)
+
+**Date:** 2026-06-05
+**Phase:** 8 of 10 (React + shadcn/ui UI redesign)
+**Tag (on completion):** `phase-8-toasts`
+
+---
+
+## 1. Goal & Non-Goals
+
+**Goal:** Add a toast notification layer to the React renderer using sonner (already installed). Surface user-initiated async action results (file save, file/folder open, exports) as transient toasts in the bottom-right of the window. The error banner pattern in export dialogs stays — toasts are a complementary global channel.
+
+**Non-goals (Phase 8):**
+- Undo/redo support (Phase 9)
+- Custom toast actions/buttons (Phase 9, if needed)
+- Persistent notification history
+- Toast queueing/throttling for rapid-fire events
+- Replacing inline error banners (they stay as per-dialog context)
+
+**Scope decision:** Toast on user-initiated actions only. Skip silent background operations (loadChildren, etc.) to avoid noise. 4 wire points total: save (success+error), open file/folder (error only), 4 export dialogs (success+error).
+
+---
+
+## 2. Architecture
+
+### 2.1 Toast helpers in `lib/toast.ts`
+
+A thin typed layer over sonner. The helpers exist to:
+- Give us a single import surface (instead of scattering `import { toast } from 'sonner'` across the codebase)
+- Provide a place to add brand colors, formatting, or analytics later without touching call sites
+- Make mocking easier in tests (one module to mock)
+
+```ts
+// src/renderer/lib/toast.ts (sketch)
+import { toast as sonnerToast } from 'sonner';
+
+export const toast = {
+  success: (message: string) => sonnerToast.success(message),
+  error: (message: string) => sonnerToast.error(message),
+  info: (message: string) => sonnerToast.info(message),
+  warning: (message: string) => sonnerToast.warning(message),
+  promise: <T>(
+    promise: Promise<T>,
+    msgs: { loading: string; success: string | ((data: T) => string); error: string | ((err: unknown) => string) }
+  ) => sonnerToast.promise(promise, msgs),
+  dismiss: (id?: string | number) => sonnerToast.dismiss(id),
+};
+```
+
+### 2.2 `<Toaster />` mounted in App.tsx
+
+A canonical shadcn Toaster wrapper (manual paste per memory `shadcn-cli-blocked-manual-primitives`). Mounts alongside `<ModalLayer />`:
+
+```tsx
+// src/renderer/App.tsx (sketch)
+import { Toaster } from '@/components/ui/sonner';
+
+function App() {
+  useWelcomeTrigger();
+  return (
+    <>
+      <AppShell />
+      <ModalLayer />
+      <Toaster />
+    </>
+  );
+}
+```
+
+The Toaster uses sonner's `<Toaster />` component with:
+- `theme={resolvedTheme}` from `useTheme()` (so toasts match the user's light/dark preference)
+- `richColors` for semantic success/error/info/warning colors
+- `position="bottom-right"` (sonner default; explicit for clarity)
+- `closeButton` (so users can dismiss)
+
+### 2.3 Inline wiring at 4 wire points
+
+**Pattern choice — inline in stores/dialogs, NOT middleware.** Matches the Phase 7 precedent of inline error banners in export dialogs. Middleware would be DRY but harder to debug and harder to control granularity (we want errors on save, but NOT on silent loadChildren).
+
+**Wire points:**
+
+1. **`useFileStore.saveActiveBuffer`** — wrap the existing logic:
+   ```ts
+   saveActiveBuffer: async () => {
+     // ... existing logic to get buffer ...
+     const writeResult = await ipc.file.write(activeTabId, buffer.content);
+     if (!writeResult.ok) {
+       toast.error(`Failed to save: ${writeResult.error.message}`);
+       return false;
+     }
+     // ... existing markSaved/markTabClean ...
+     toast.success(`Saved ${title}`);
+     return true;
+   }
+   ```
+
+2. **`useFileStore.openFile`** — error only:
+   ```ts
+   openFile: async (filePath) => {
+     // ... existing logic to check existing tab ...
+     const result = await ipc.file.read(filePath);
+     if (!result.ok) {
+       toast.error(`Failed to open file: ${result.error.message}`);
+       return;
+     }
+     // ... existing logic ...
+   }
+   ```
+
+3. **`useFileStore.openFolder`** — error only:
+   ```ts
+   openFolder: async (path) => {
+     const result = await ipc.file.list(path);
+     if (!result.ok) {
+       toast.error(`Failed to open folder: ${result.error.message}`);
+       return;
+     }
+     // ... existing logic ...
+   }
+   ```
+
+4. **4 export dialogs** — both success and error (error complements the inline banner):
+   ```ts
+   if (!result.ok) {
+     toast.error(`Export failed: ${result.error.message}`);
+     setError(result.error.message);
+     setSubmitting(false);
+   } else {
+     toast.success(`Exported ${source.title} to ${result.data?.outputPath ?? 'file'}`);
+     closeModal();
+   }
+   ```
+
+---
+
+## 3. File Map
+
+### 3.1 Created files
+
+- `src/renderer/lib/toast.ts` — typed wrappers (re-export of sonner with our naming)
+- `src/renderer/components/ui/sonner.tsx` — canonical shadcn Toaster wrapper (manual paste)
+- `tests/unit/lib/toast.test.ts` — ~5 unit tests
+- `tests/component/ui/sonner.test.tsx` — 1 smoke test
+- `tests/integration/phase8-toasts-smoke.test.tsx` — ~4 integration tests
+
+### 3.2 Modified files
+
+- `src/renderer/App.tsx` — mount `<Toaster />` alongside `<ModalLayer />`
+- `src/renderer/stores/file-store.ts` — add 3 toast calls (save, openFile, openFolder)
+- `src/renderer/components/modals/ExportPdfDialog.tsx` — toast on submit result
+- `src/renderer/components/modals/ExportDocxDialog.tsx` — toast on submit result
+- `src/renderer/components/modals/ExportHtmlDialog.tsx` — toast on submit result
+- `src/renderer/components/modals/ExportBatchDialog.tsx` — toast on submit result
+
+---
+
+## 4. Data Flow
+
+User action → store action OR export dialog submit → IPC call → result →
+- if error: `toast.error(message)` → sonner renders in bottom-right portal
+- if success: `toast.success(message)` → sonner renders
+- inline error banner in dialog stays as per-dialog context (NOT removed)
+
+Theme comes from `useTheme()` in the Toaster component, not from individual toasts. The Toaster is mounted once at the app level.
+
+For the 4 export dialogs: the existing inline error banner stays (it's contextual to the dialog), AND a toast is fired. This gives the user both immediate context (in the dialog) and persistent notification (toast in corner).
+
+For file save: ONLY a toast (no inline error UI in the editor pane — keeps the editor clean). Errors still show the toast.
+
+---
+
+## 5. Error Handling
+
+- **Toast helpers never throw.** They are thin re-exports of sonner, which handles its own error cases (e.g., render failures, missing portal target).
+- **In tests**, the `toast` module is mocked so calls don't render real toasts. Mock signature: `vi.mock('@/lib/toast', () => ({ toast: { success: vi.fn(), error: vi.fn(), ... } }))`.
+- **Theme fallback:** If `useTheme()` is loading or `resolvedTheme` is undefined, Toaster uses `'system'` as a fallback (sonner's default behavior).
+- **Sonner missing:** If for some reason sonner fails to load, the toast calls become no-ops. The user still sees inline error banners in the export dialogs.
+- **Inline error banners stay.** They are not replaced by toasts — they complement them.
+
+---
+
+## 6. Testing Strategy
+
+### 6.1 Unit tests (`tests/unit/lib/toast.test.ts`)
+
+5 tests:
+- `toast.success` calls sonner `toast.success` with the message
+- `toast.error` calls sonner `toast.error` with the message
+- `toast.info` calls sonner `toast.info`
+- `toast.warning` calls sonner `toast.warning`
+- `toast.promise` forwards the promise and messages to sonner
+
+All tests mock the sonner module and verify the forwarded call.
+
+### 6.2 Component test (`tests/component/ui/sonner.test.tsx`)
+
+1 smoke test: `<Toaster />` renders without crashing inside a ThemeProvider.
+
+### 6.3 Integration test (`tests/integration/phase8-toasts-smoke.test.tsx`)
+
+~4 tests:
+- Saving a file → `toast.success` called with `"Saved test.md"`
+- Opening a non-existent file (ipc returns error) → `toast.error` called with file path in message
+- Export success (ipc returns ok) → `toast.success` called + dialog closes
+- Export failure (ipc returns error) → `toast.error` called + inline banner shown + dialog stays open
+
+TDD throughout. Mocks for `ipc.*` and `lib/toast`.
+
+### 6.4 Existing tests must still pass
+
+- All 243 tests from Phase 7 must remain green
+- Export dialog tests will need updates to verify the new toast calls (the dialog tests currently check for inline banner; they should ALSO verify the toast call)
+
+---
+
+## 7. Risks & Open Questions
+
+**Risks:**
+- **Sonner theme switching:** If `useTheme()` returns `'system'` and the OS preference changes mid-session, sonner will re-render. This is the correct behavior; just confirm in test.
+- **Toast spam:** If user holds Cmd+S, the save could fire many times. Sonner deduplicates by default for similar messages? → Decision: rely on sonner's default behavior. If spam becomes an issue, add a `toast.dismiss()` debounce in v2.
+
+**Open questions (deferrable):**
+- Should we add a custom toast for "undo last close" (Phase 9's undo feature)? → Decision: out of scope for Phase 8. Phase 9 will handle undo toasts.
+- Should the export dialog inline banner be removed once toasts are wired? → Decision: NO — keep both. The inline banner is contextual to the dialog; the toast is global. They serve different purposes.
+
+---
+
+## 8. Out of Scope (deferred to later phases)
+
+- Phase 9: Undo toasts ("Tab closed — Undo" with action button)
+- Phase 9: Long-running operation progress toasts (e.g., batch export queue)
+- Phase 9: Custom toast variants for advanced tools (ASCII generator, table generator)
+- Phase 10: Cleanup of inline error banners (will evaluate in Phase 10 if redundant)
+
+---
+
+## 9. Success Criteria
+
+Phase 8 is complete when:
+- `lib/toast.ts` exists with typed wrappers
+- `<Toaster />` is mounted in `App.tsx` and renders toasts
+- `useFileStore.saveActiveBuffer` calls `toast.success`/`toast.error` on result
+- `useFileStore.openFile` calls `toast.error` on failure
+- `useFileStore.openFolder` calls `toast.error` on failure
+- 4 export dialogs call `toast.success`/`toast.error` on result
+- All tests pass: ~+10 new tests, total ~253
+- `npx vite build` succeeds
+- Branch tagged `phase-8-toasts` and pushed to origin

docs/superpowers/specs/2026-06-05-react-ui-redesign-design.md

@@ -0,0 +1,361 @@
+# MarkdownConverter — React + shadcn/ui UI Redesign
+
+**Date:** 2026-06-05
+**Status:** Design (awaiting user approval)
+**Branch:** `react-electron`
+**Author:** Brainstormed with user via superpowers:brainstorming
+
+## Summary
+
+Replace the legacy vanilla JS renderer (`src/renderer.js` is 213 KB; `src/styles.css` is 74 KB) with a modern React 19 + Vite + TypeScript + shadcn/ui renderer that achieves visual feature parity while delivering a Polished + Glassy (Raycast/Arc-style) aesthetic. The Electron main process, preload bridge, and IPC contracts stay unchanged. Work proceeds via vertical slices — each PR ships a demoable feature.
+
+## Goals
+
+1. Replace every render-time feature of the legacy renderer with an idiomatic React + shadcn/ui implementation.
+2. Adopt the "Polished + Glassy" visual language (subtle shadows, 8–12 px radii, gradient accents, gentle depth) on top of the existing ConcreteInfo brand tokens and design system.
+3. Use a single component foundation (shadcn/ui) and a single motion library (Motion / Framer Motion) to keep the dependency surface narrow and the design coherent.
+4. Keep the main process, preload, and IPC contracts untouched. The renderer is the only surface being rewritten.
+5. Keep the app runnable at every commit. No "big bang" merge.
+
+## Non-Goals
+
+- Migrating the main process to TypeScript (out of scope for this spec).
+- Adding new features the legacy renderer does not have (plugin system, AI features, etc. — those are future specs).
+- Replacing Pandoc/FFmpeg/ImageMagick orchestration.
+- Changing the packaging pipeline (electron-builder config stays).
+- Replacing the CodeMirror 6 editor — it is the right tool and is already wired up.
+
+## Decisions Locked During Brainstorming
+
+| Decision | Choice | Why |
+|---|---|---|
+| Scope | Full feature parity with legacy renderer | User-selected option. Renderer is one cohesive surface; splitting it across specs would force premature contracts. |
+| Visual style | **B — Polished + Glassy** (Raycast/Arc aesthetic) | "Fancy" comes from elevation, gradient accents, and material depth — not over-designed visuals. |
+| Layout | **2 — IDE-style** (equal editor/preview, draggable divider, collapsible sidebar) | Power-user markdown apps converge on this. Draggable divider + keyboard reset. |
+| Modal patterns | **A (Centered Dialog), B (Right Side-Sheet), D (Toasts)** | No command palette. |
+| Command palette | **No** — full menus, no ⌘K | Power users can use the OS-level launcher. App stays focused on writing. |
+| Animation | **Motion (Framer Motion)** | Best for layout transitions, modal/drawer enter/exit, drag. Sparingly used. |
+| Component library | **shadcn/ui** | Tailwind + Radix primitives, copy-paste ownership, perfect fit for the "glassy" aesthetic and the HSL-CSS-variable foundation that is already in place. |
+| Implementation strategy | **Vertical slices** — one feature end-to-end per PR | App stays runnable. Each PR is reviewable. |
+
+## Defaults (Used Unless Overridden Later)
+
+| Item | Default | Why |
+|---|---|---|
+| State management | Zustand (already in deps) + Immer for nested patches | Already in `package.json`; perfect for editor state. |
+| Theming | shadcn `next-themes`, dark default + light, system-aware | shadcn canonical pattern. Brand colors already in CSS vars. |
+| Icons | `lucide-react` (already in deps) | 1000+ tree-shakable icons. |
+| Forms | `react-hook-form` + `zod` | Standard for shadcn forms. |
+| Drag/drop (sortable lists) | `@dnd-kit/core` | De facto React drag lib (file tree reordering, plugin list reorder). |
+| Pane resize (split layout) | `react-resizable-panels` | Canonical React lib for resizable pane groups; handles drag, arrow keys, snap, persisted sizes. |
+| Testing | Vitest + RTL + Playwright (E2E + visual regression) | Standard for React + Electron. |
+| TypeScript | Strict mode (already wired) | Already in deps and `vite.renderer.config.ts`. |
+
+## Architecture
+
+The Electron app keeps its existing process model. Only the renderer is rewritten.
+
+```
+┌──────────────────────────────────────────────────────────┐
+│  Electron Main (UNCHANGED)                                │
+│  - BrowserWindow, IPC handlers, file/fs ops               │
+│  - Pandoc, FFmpeg, ImageMagick orchestration              │
+└────────────┬─────────────────────────────────────────────┘
+             │ contextBridge (UNCHANGED preload.js)
+┌────────────▼─────────────────────────────────────────────┐
+│  React Renderer (REWRITTEN)                                │
+│  ┌────────────────────────────────────────────────────┐  │
+│  │  AppShell (layout)                                  │  │
+│  │  ├─ MenuBar (native)                                │  │
+│  │  ├─ AppHeader (logo, breadcrumbs, theme toggle)     │  │
+│  │  ├─ TabBar (open files)                             │  │
+│  │  ├─ Toolbar (formatting)                            │  │
+│  │  ├─ ResizablePaneGroup (sidebar | editor | preview) │  │
+│  │  │   ├─ Sidebar (file tree, outline)                │  │
+│  │  │   ├─ EditorPane (CodeMirror 6)                   │  │
+│  │  │   └─ PreviewPane (marked + KaTeX + Mermaid)      │  │
+│  │  ├─ StatusBar (word count, encoding, cursor pos)    │  │
+│  │  └─ ModalLayer (Dialog, SideSheet, Toaster)         │  │
+│  └────────────────────────────────────────────────────┘  │
+│  ┌────────────────────────────────────────────────────┐  │
+│  │  Feature Modules (each owns UI + state slice)       │  │
+│  │  ├─ editor/    CodeMirror wrapper, syntax, themes   │  │
+│  │  ├─ preview/   markdown→html, KaTeX, Mermaid       │  │
+│  │  ├─ tabs/      open files, dirty state              │  │
+│  │  ├─ sidebar/   file tree, outline, search results   │  │
+│  │  ├─ modals/    export, settings, about, etc.        │  │
+│  │  ├─ tools/     zen, repl, ascii-gen, table-gen      │  │
+│  │  └─ export/    pdf, docx, html, image batch         │  │
+│  └────────────────────────────────────────────────────┘  │
+│  ┌────────────────────────────────────────────────────┐  │
+│  │  Shared Infrastructure                              │  │
+│  │  ├─ stores/  Zustand slices per feature             │  │
+│  │  ├─ hooks/   useFile, useEditor, useTheme, etc.     │  │
+│  │  ├─ lib/     cn, ipc, formatters, validators        │  │
+│  │  ├─ ui/      shadcn primitives: button, dialog…     │  │
+│  │  └─ types/   shared TS types                        │  │
+│  └────────────────────────────────────────────────────┘  │
+└──────────────────────────────────────────────────────────┘
+```
+
+### Architectural Rules
+
+- **Shell components** (`AppHeader`, `TabBar`, `StatusBar`) subscribe only to `useAppStore`.
+- **Feature components** subscribe to their own feature's store.
+- **Cross-feature access** goes through hooks, not direct store imports (e.g., `useFileTree()` wraps `useFileStore`).
+- **Feature modules are self-contained** — each owns its components, its Zustand slice, and its types. Safe to develop in parallel later.
+- **No direct `window.electronAPI` calls** from feature code. All IPC goes through `lib/ipc.ts` for type safety and error normalization.
+
+## State Management
+
+```
+stores/
+├─ useAppStore        // global UI: theme, sidebar, pane sizes, modals open
+├─ useFileStore       // file system: tree, open files, active tab
+├─ useEditorStore     // editor: per-file content, cursor, selection, dirty
+├─ usePreviewStore    // preview: scroll sync, zoom, theme
+├─ useSettingsStore   // user prefs (persisted to electron-store)
+└─ useCommandStore    // menu actions registry, recent actions
+```
+
+**Why slices instead of one mega-store?** Editor content can be megabytes. Keeping it in its own slice lets React avoid re-rendering the preview when only the editor changes — components subscribe with selectors.
+
+**Persistent state** (auto-saved to electron-store via Zustand `persist` middleware): theme, sidebar visibility, last open files, pane divider positions, settings.
+
+**Ephemeral state** (lost on quit): active modal, hover states, search query, current file content (saved to disk on idle).
+
+## Visual Design System
+
+### Color Tokens
+
+The existing `globals.css` HSL variables stay. Additions for the "glassy" aesthetic:
+
+```css
+--shadow-sm: 0 1px 2px rgba(13, 11, 9, 0.06);
+--shadow-md: 0 4px 12px rgba(13, 11, 9, 0.08), 0 0 0 1px rgba(13, 11, 9, 0.04);
+--shadow-lg: 0 12px 32px rgba(13, 11, 9, 0.12), 0 0 0 1px rgba(13, 11, 9, 0.06);
+--shadow-glow-brand: 0 0 24px rgba(229, 70, 31, 0.25);
+
+--glass-bg-light: rgba(255, 255, 255, 0.72);
+--glass-bg-dark:  rgba(13, 11, 9, 0.72);
+--glass-border-light: rgba(255, 255, 255, 0.4);
+--glass-border-dark:  rgba(255, 255, 255, 0.08);
+```
+
+### shadcn Components
+
+Install via `npx shadcn@latest add`:
+
+**Primitives** (need all of these): `button`, `dialog`, `sheet`, `popover`, `tooltip`, `select`, `dropdown-menu`, `tabs`, `separator`, `scroll-area`, `toggle`, `switch`, `slider`, `input`, `textarea`, `label`, `form`, `skeleton`, `sonner`, `command`.
+
+**Composite** (custom-built on top of primitives): `file-tree`, `pane-group`, `divider`, `status-bar`, `menu-bar`, `toast`.
+
+### Typography
+
+- Body: Plus Jakarta Sans 15 px / line-height 1.6
+- Code: JetBrains Mono 13.5 px
+- Display: Barlow Condensed 700/800 — used sparingly (page titles, big metrics)
+- Headings: Plus Jakarta Sans 600/700 with tight letter-spacing
+- Labels (`.label`): Plus Jakarta Sans 500, 12 px, uppercase, 0.05 em letter-spacing
+
+### Motion Choreography
+
+| Element | Motion | Duration | Easing |
+|---|---|---|---|
+| Modal (Dialog A) | Scale 0.96→1, opacity 0→1 | 200 ms | `ease-out` |
+| Side sheet (B) | TranslateX 100%→0, opacity 0→1 | 300 ms | `cubic-bezier(0.16, 1, 0.3, 1)` |
+| Toast | TranslateY 100%→0, opacity | 250 ms | spring(stiffness: 300, damping: 30) |
+| Sidebar toggle | Width 264 px↔72 px, content fade | 250 ms | `ease-in-out` |
+| Divider drag | Live width update | 0 ms | none (instant) |
+| Theme switch | CSS variables, opacity overlay | 300 ms | `ease-in-out` |
+| Tab switch | Underline slide | 200 ms | `ease-out` |
+| Hover (buttons) | `bg` + `shadow` shift | 150 ms | `ease-out` |
+| Focus ring | Outline grow | 100 ms | `ease-out` |
+
+**Rules:** Every motion has a purpose. No gratuitous animation. Respects `prefers-reduced-motion` (Motion handles this automatically).
+
+### Empty / Loading / Error States
+
+Every async surface ships all three. Sonner toasts for ephemeral feedback. Skeleton screens for content areas. Empty-state components with icon + message + primary CTA.
+
+## Modal/Overlay Patterns
+
+| Use case | Pattern | Why |
+|---|---|---|
+| Export (PDF/DOCX/HTML) | A — Centered Dialog | Focused decision, ~3–5 fields, "do one thing" |
+| Settings | B — Right Side-Sheet | Long form, tabbed sections, stays open while editing |
+| Find/Replace | Inline toolbar (not modal) | Always-visible utility |
+| About | A — Centered Dialog | Tiny info dump |
+| Confirm destructive (delete, close unsaved) | A — Centered Dialog | Forces attention |
+| File save error | D — Toast | Non-blocking info |
+| Pandoc/FFmpeg progress | D — Toast → sticky on >3 s | Background work feedback |
+| Plugin manager | B — Right Side-Sheet | Lists + per-item actions |
+| ASCII/Table generators | A — Centered Dialog | Tool-style focused input → output |
+| Print preview | A — Centered Dialog | Full-screen-ish modal overlay |
+| Welcome (first launch) | A — Centered Dialog | One-time onboarding |
+| Word export | A — Centered Dialog | Template selection |
+| Zen mode | Full-viewport toggle (no modal) | Replaces the editor entirely |
+| REPL | Bottom-pinned panel (split-pane) | Persistent terminal-like UI |
+| Quick file open | B — Right Side-Sheet | File tree, search, recent |
+
+### Dialog A Anatomy (Export as example)
+
+```
+┌─ Backdrop (rgba(13,11,9,0.45) + backdrop-blur 4px) ─────────┐
+│                                                            │
+│   ┌──── Modal (max-w-md, rounded-2xl, shadow-lg) ─────┐    │
+│   │ ┌── Header ────────────────────────────────────┐  │    │
+│   │ │ [Icon] Export as PDF                  [×]    │  │    │
+│   │ │ Choose format options                       │  │    │
+│   │ └─────────────────────────────────────────────┘  │    │
+│   │ ┌── Body ──────────────────────────────────────┐  │    │
+│   │ │ Format: [Letter] [A4] [Legal]                │  │    │
+│   │ │ Margins: ────●────                           │  │    │
+│   │ │ ☐ Include table of contents                  │  │    │
+│   │ │ ☐ Embed fonts                                │  │    │
+│   │ └─────────────────────────────────────────────┘  │    │
+│   │ ┌── Footer ────────────────────────────────────┐  │    │
+│   │ │                       [Cancel] [Export →]    │  │    │
+│   │ └─────────────────────────────────────────────┘  │    │
+│   └──────────────────────────────────────────────────┘    │
+│                                                            │
+└────────────────────────────────────────────────────────────┘
+```
+
+### Side-Sheet B Anatomy (Settings as example)
+
+Slides in from right, ~50 % width (max 560 px). Backdrop is `rgba(13,11,9,0.2)` with `backdrop-blur(2 px)` (lighter than dialog — the sheet is the focus). Tab navigation in the sheet header (Editor / Theme / Export / Plugins / About).
+
+### Toast D Anatomy (Sonner)
+
+Stacked bottom-right, max 3 visible. Glass background. Color-coded 3 px left border — success `#1a7a56`, error `#ef4444`, info `#0ea5e9`, warning `#eab308`. Icon + title + description. Optional action button. Auto-dismiss 4 s for success, sticky for error.
+
+## Data Flow (Editor → Preview Pipeline)
+
+```
+User types
+  ↓
+CodeMirror onChange
+  ↓
+useEditorStore.updateContent(tabId, content)  ← debounced 50 ms
+  ↓
+┌─ Persist to electron-store on idle (1 s) ─┐
+│                                            │
+└─ Publish to usePreviewStore (subscribed) ─┘
+  ↓
+marked(content) → sanitized HTML
+  ↓
+PreviewPane renders HTML
+  KaTeX post-processes $...$
+  Mermaid post-processes ```mermaid
+  Highlight.js post-processes ```lang
+  ↓
+useEffect: scroll-sync editor cursor → preview position
+```
+
+**Bidirectional scroll sync:** editor scroll → preview (primary), preview click → editor cursor (secondary). Throttled to 60 fps via `requestAnimationFrame`.
+
+## IPC Contract
+
+The preload bridge stays unchanged. A new `src/renderer/lib/ipc.ts` wraps every channel with TypeScript types and normalizes errors to a discriminated union:
+
+```ts
+type IpcResult<T> =
+  | { ok: true; data: T }
+  | { ok: false; error: { code: string; message: string } };
+
+export const ipc = {
+  file: {
+    open: (): Promise<IpcResult<FileResult>>,
+    read: (path: string): Promise<IpcResult<string>>,
+    write: (path: string, content: string): Promise<IpcResult<void>>,
+    list: (dir: string): Promise<IpcResult<FileEntry[]>>,
+    onChange: (cb: (path: string) => void) => () => void,
+  },
+  export: {
+    pdf: (opts: PdfOptions): Promise<IpcResult<ExportResult>>,
+    docx: (opts: DocxOptions): Promise<IpcResult<ExportResult>>,
+    html: (opts: HtmlOptions): Promise<IpcResult<ExportResult>>,
+    batch: (items: BatchItem[], opts: BatchOptions): Promise<IpcResult<BatchResult>>,
+  },
+  app: {
+    getVersion: (): Promise<IpcResult<string>>,
+    openExternal: (url: string): Promise<IpcResult<void>>,
+    showItemInFolder: (path: string): Promise<IpcResult<void>>,
+  },
+};
+```
+
+## Error Handling
+
+Layered defense — no single failure can crash the app:
+
+1. **IPC errors** → caught in `lib/ipc.ts` wrapper, returned as `IpcResult<T>` discriminated union. Components show toast on error.
+2. **Component errors** → React error boundary per feature area (one for editor, one for preview, one for modals). On error: show inline error UI with "Reload this panel" + "Copy details" actions.
+3. **Async operations** (export, file ops) → loading state on button + toast on completion. Long ops (>2 s) get a sticky toast with cancel.
+4. **Validation errors** (settings, export options) → inline form errors via `react-hook-form` + `zod`. shadcn `Form` component for consistent error display.
+5. **Pandoc/FFmpeg missing** → detected at startup, banner + disable export menu items. Don't surprise-fail at export time.
+
+## Testing Strategy
+
+- **Unit (Vitest):** stores, hooks, lib utilities, formatters, validators
+- **Component (Vitest + RTL):** shadcn wrappers, dialog interactions, sidebar toggle, divider drag, theme toggle
+- **Integration (Vitest + RTL):** editor ↔ preview flow, file open → tab add → content display, settings change persists
+- **E2E (Playwright):** app launches, file opens, markdown renders, export to PDF works
+- **Visual regression (Playwright snapshots):** locked-in screenshots for header, sidebar, dialogs, toasts — catch accidental style drift
+- **Target coverage:** stores/hooks/lib ≥ 90 %, components ≥ 75 %, E2E covers all critical paths
+
+## Accessibility (WCAG 2.1 AA)
+
+Baked in via shadcn + Radix:
+
+- All dialogs focus-trap, Esc to close, return focus to trigger
+- All interactive elements keyboard-reachable
+- Visible focus rings (2 px brand ring)
+- 4.5:1 contrast minimum (already met by brand colors)
+- `aria-label` on icon buttons, `role="alert"` on toasts
+- Respects `prefers-reduced-motion` (Motion handles this automatically)
+
+## Implementation Phases (Vertical Slices)
+
+Each phase is a shippable PR that keeps the app runnable. The legacy `renderer.js` is gradually replaced; until each phase is complete, the old renderer code still runs the missing parts.
+
+| # | Phase | Output | Acceptance |
+|---|---|---|---|
+| 1 | **Foundation** | shadcn installed; `next-themes`, `motion`, `react-hook-form`, `zod`, `@dnd-kit/core`, `react-resizable-panels`, `sonner` installed; design tokens finalized; `lib/utils.ts` (`cn`), `lib/ipc.ts` typed wrappers, `lib/motion.ts` preset transitions, `App.tsx` shell skeleton renders | `npm run build` succeeds; dev server shows the new shell with theme toggle working |
+| 2 | **App shell + layout** | `AppHeader`, `TabBar`, `Toolbar`, `Breadcrumb`, `StatusBar`, `ResizablePaneGroup` with sidebar toggle and draggable divider. Empty editor/preview panes. | Resize divider with mouse and arrow keys; sidebar collapses; pane sizes persist. |
+| 3 | **Editor pane** | CodeMirror 6 wrapped, dark/light themes wired to shadcn theme, syntax highlighting, line numbers, search, autocomplete | Open `.md` file → renders in editor; can edit and save. |
+| 4 | **Preview pane** | marked + DOMPurify + KaTeX + Mermaid + highlight.js. Bidirectional scroll sync with editor. | Open file → preview renders, follows cursor. |
+| 5 | **File tree + tabs** | Sidebar file tree (read directory on demand, lazy-expand children only on click). Tabs for open files. Dirty state indicator. File content is read from disk only when the tab is activated. | Open folder → root populates; click folder → children load; click file → opens in tab; close tab reverts dirty. |
+| 6 | **Native menus + toolbar** | Replace the legacy `CommandPalette` with full menus (File / Edit / View / Insert / Format / Tools / Help) bound to keyboard shortcuts. Toolbar buttons. | All menu items invoke the right action; shortcuts work; toolbar reflects active state. |
+| 7 | **Modals** | Export dialog (PDF/DOCX/HTML/batch), Settings side-sheet (Editor/Theme/Export/Plugins/About tabs), About dialog, Confirm-destructive dialog | All dialogs and sheet render with proper motion; settings persist; export works end-to-end. |
+| 8 | **Toasts** | Sonner wired into all async operations (save, export, errors, tool missing) | All operations give appropriate feedback; no silent failures. |
+| 9 | **Advanced tools** | Zen mode (full-viewport toggle), REPL (bottom-pinned panel), ASCII generator, Table generator, Word export template picker, Print preview | Each tool is feature-complete vs. legacy version. |
+| 10 | **Polish + delete legacy** | Visual regression snapshots locked; remove `renderer.js` and old `styles*.css` references from build; `npm run build:linux` produces a working installer | Final PR ships an installer with no legacy code paths. |
+
+## Risks and Mitigations
+
+| Risk | Mitigation |
+|---|---|
+| shadcn CLI requires Vite (not vanilla Electron renderer) | Vite is already configured for the renderer in `vite.renderer.config.ts`; the CLI works against the same project. |
+| shadcn CLI assumes Tailwind is at project root; we have it in renderer/ only | Point the CLI at `src/renderer/components.json` and set `tailwind.css` to the right path. |
+| Marked + KaTeX + Mermaid + highlight.js together is heavy | Lazy-load Mermaid (only when `mermaid` code block encountered). KaTeX is loaded once, cached. |
+| Editor content state can be megabytes → re-render storms | Editor content lives in its own slice; preview subscribes to a derived/cached HTML string; components use `useShallow` / selector subscriptions. |
+| Bidirectional scroll sync loops | `useEffect` debounce + ignore if cursor/selection is the sync source. |
+| CodeMirror 6 doesn't ship a Tailwind theme by default | Use `@codemirror/theme-one-dark` for dark; build a custom theme that pulls from CSS variables for light. |
+| The legacy `renderer.js` and `styles*.css` are referenced from `index.html` (now `src/renderer/index.html`) | Phase 10 deletes the references; until then, both run side-by-side and the new React app sits in a known root div. |
+| Electron `nodeIntegration` is off; we use contextBridge | Already the case. Document the contract clearly in `lib/ipc.ts`. |
+
+## Open Questions (to confirm before implementation)
+
+None. All major decisions are locked. Defaults will be used unless the user overrides them when reviewing the implementation plan.
+
+## References
+
+- `src/renderer.js` (213 KB) — legacy renderer being replaced
+- `src/styles.css` (74 KB), `src/styles-modern.css` (71 KB), `src/styles-concreteinfo.css` (21 KB) — legacy styles being replaced
+- `src/renderer/styles/globals.css` — already shadcn-compatible (HSL CSS variables)
+- `src/renderer/App.tsx` — empty skeleton that references components we will build
+- `tailwind.config.js` — brand colors and fonts already defined
+- `vite.renderer.config.ts` — Vite + React plugin already configured
+- `package.json` — CodeMirror 6, TanStack Table, lucide-react, cva, clsx, tailwind-merge, tailwindcss-animate already installed

package.json

@@ -1,6 +1,6 @@
 {
   "name": "markdown-converter",
-  "version": "4.4.1",
+  "version": "4.4.2",
   "description": "Professional Markdown editor and universal file converter with PDF editing, batch processing, and syntax highlighting",
   "main": "src/main.js",
   "scripts": {
@@ -8,6 +8,9 @@
     "test": "jest",
     "test:watch": "jest --watch",
     "test:coverage": "jest --coverage",
+    "test:renderer": "vitest run",
+    "test:renderer:watch": "vitest",
+    "test:renderer:coverage": "vitest run --coverage",
     "lint": "eslint src tests",
     "lint:fix": "eslint src tests --fix",
     "format": "prettier --write src tests",
@@ -43,7 +46,19 @@
     "url": "https://github.com/amitwh/markdown-converter"
   },
   "devDependencies": {
+    "@playwright/test": "^1.60.0",
     "@testing-library/dom": "^10.4.1",
+    "@testing-library/jest-dom": "^6.9.1",
+    "@testing-library/react": "^16.3.2",
+    "@testing-library/user-event": "^14.6.1",
+    "@types/node": "^25.9.1",
+    "@types/react": "^19.2.16",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^6.0.2",
+    "@vitest/ui": "^4.1.8",
+    "autoprefixer": "^10.5.0",
+    "class-variance-authority": "^0.7.1",
+    "clsx": "^2.1.1",
     "cross-env": "^10.0.0",
     "electron": "^41.1.1",
     "electron-builder": "^26.0.12",
@@ -52,8 +67,17 @@
     "eslint-plugin-prettier": "^5.5.4",
     "jest": "^30.2.0",
     "jest-environment-jsdom": "^30.2.0",
+    "jsdom": "^29.1.1",
+    "lucide-react": "^1.17.0",
+    "postcss": "^8.5.15",
     "prettier": "^3.7.4",
-    "sharp": "^0.34.3"
+    "sharp": "^0.34.3",
+    "tailwind-merge": "^3.6.0",
+    "tailwindcss": "^3.4.19",
+    "tailwindcss-animate": "^1.0.7",
+    "typescript": "^6.0.3",
+    "vite": "^8.0.16",
+    "vitest": "^4.1.8"
   },
   "dependencies": {
     "@codemirror/autocomplete": "^6.20.1",
@@ -70,25 +94,52 @@
     "@codemirror/state": "^6.5.4",
     "@codemirror/theme-one-dark": "^6.1.3",
     "@codemirror/view": "^6.39.16",
+    "@dnd-kit/core": "^6.3.1",
+    "@dnd-kit/sortable": "^10.0.0",
+    "@dnd-kit/utilities": "^3.2.2",
+    "@hookform/resolvers": "^5.4.0",
+    "@radix-ui/react-checkbox": "^1.3.3",
+    "@radix-ui/react-collapsible": "^1.1.12",
+    "@radix-ui/react-context-menu": "^2.2.16",
+    "@radix-ui/react-dialog": "^1.1.15",
+    "@radix-ui/react-label": "^2.1.8",
+    "@radix-ui/react-radio-group": "^1.3.8",
+    "@radix-ui/react-scroll-area": "^1.2.10",
+    "@radix-ui/react-select": "^2.2.6",
+    "@radix-ui/react-slider": "^1.3.6",
+    "@radix-ui/react-slot": "^1.2.4",
+    "@radix-ui/react-switch": "^1.2.6",
+    "@radix-ui/react-tabs": "^1.1.13",
+    "@tanstack/react-table": "^8.21.3",
     "codemirror": "^6.0.2",
     "core-util-is": "^1.0.3",
     "docx": "^9.6.0",
-    "docx4js": "^3.3.0",
+    "docx4js": "^2.0.1",
     "dompurify": "^3.3.1",
     "electron-store": "^10.1.0",
     "ffmpeg-static": "^5.3.0",
     "highlight.js": "^11.11.1",
     "html2pdf.js": "^0.14.0",
+    "immer": "^11.1.8",
     "marked": "^17.0.3",
     "marked-footnote": "^1.4.0",
     "marked-highlight": "^2.2.3",
     "mermaid": "^11.12.3",
+    "motion": "^12.40.0",
+    "next-themes": "^0.4.6",
     "pdf-lib": "^1.17.1",
     "pdfjs-dist": "^5.5.207",
     "pdfkit": "^0.17.2",
     "pizzip": "^3.2.0",
+    "react": "^19.2.7",
+    "react-dom": "^19.2.7",
+    "react-hook-form": "^7.77.0",
+    "react-resizable-panels": "^4.11.2",
     "simple-git": "^3.32.3",
-    "tslib": "^2.8.1"
+    "sonner": "^2.0.7",
+    "tslib": "^2.8.1",
+    "zod": "^4.4.3",
+    "zustand": "^5.0.14"
   },
   "overrides": {
     "jszip": "^3.10.1",
@@ -170,7 +221,10 @@
       "verifyUpdateCodeSignature": false,
       "signAndEditExecutable": false,
       "extraFiles": [
-        { "from": "bin/win32/pandoc.exe", "to": "bin/pandoc.exe" }
+        {
+          "from": "bin/win32/pandoc.exe",
+          "to": "bin/pandoc.exe"
+        }
       ]
     },
     "nsis": {
@@ -198,7 +252,10 @@
       "category": "Utility",
       "maintainer": "ConcreteInfo <amit.wh@gmail.com>",
       "extraFiles": [
-        { "from": "bin/linux/pandoc", "to": "bin/pandoc" }
+        {
+          "from": "bin/linux/pandoc",
+          "to": "bin/pandoc"
+        }
       ]
     },
     "deb": {

postcss.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+}

src/index.html

@@ -4,7 +4,7 @@
     <meta charset="UTF-8">
     <!-- CSP: unsafe-inline/unsafe-eval required for marked.js extensions and Mermaid -->
     <!-- TODO: Migrate to nonce-based CSP for better security -->
-    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self' data:; connect-src 'self' https://www.plantuml.com;">
+    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net; style-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net; img-src 'self' data: blob:; font-src 'self' data: https://cdn.jsdelivr.net; connect-src 'self' https://www.plantuml.com;">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>MarkdownConverter</title>
     <!-- Design tokens - loaded first for CSS variable availability -->
@@ -288,6 +288,52 @@
                         </div>
                     </div>
 
+                    <div class="export-section revealjs-only" style="display: none;">
+                        <label>Reveal.js Options:</label>
+                        <div class="form-row">
+                            <label for="reveal-theme">Slide Theme:</label>
+                            <select id="reveal-theme">
+                                <option value="black">Black</option>
+                                <option value="white">White</option>
+                                <option value="league">League</option>
+                                <option value="beige">Beige</option>
+                                <option value="sky">Sky</option>
+                                <option value="night">Night</option>
+                                <option value="serif">Serif</option>
+                                <option value="simple">Simple</option>
+                                <option value="solarized">Solarized</option>
+                                <option value="blood">Blood</option>
+                                <option value="moon">Moon</option>
+                            </select>
+                        </div>
+                        <div class="form-row">
+                            <label for="reveal-transition">Transition:</label>
+                            <select id="reveal-transition">
+                                <option value="slide">Slide</option>
+                                <option value="none">None</option>
+                                <option value="fade">Fade</option>
+                                <option value="convex">Convex</option>
+                                <option value="concave">Concave</option>
+                                <option value="zoom">Zoom</option>
+                            </select>
+                        </div>
+                        <div class="form-row">
+                            <label for="reveal-speed">Transition Speed:</label>
+                            <select id="reveal-speed">
+                                <option value="default">Default</option>
+                                <option value="fast">Fast</option>
+                                <option value="slow">Slow</option>
+                            </select>
+                        </div>
+                        <div class="checkbox-group">
+                            <label><input type="checkbox" id="reveal-slide-number"> Slide Numbers</label>
+                            <label><input type="checkbox" id="reveal-controls" checked> Controls</label>
+                            <label><input type="checkbox" id="reveal-progress" checked> Progress Bar</label>
+                            <label><input type="checkbox" id="reveal-history" checked> Slide History</label>
+                            <label><input type="checkbox" id="reveal-center" checked> Center Content</label>
+                        </div>
+                    </div>
+
                     <div class="export-section">
                         <label>Bibliography:</label>
                         <div class="form-row">
@@ -905,6 +951,7 @@
                     <button class="modal-close" id="pdf-editor-dialog-close" aria-label="Close">&times;</button>
                 </div>
                 <div class="modal-body pdf-editor-body">
+                    <div class="pdf-editor-left-panel">
                     <!-- Merge PDFs Section -->
                     <div id="pdf-merge-section" class="pdf-operation-section hidden">
                         <div class="export-section">
@@ -1287,6 +1334,16 @@
                         </div>
                     </div>
                 </div>
+
+                <!-- Right Panel: Scrollable Visual Page Sidebar -->
+                <div id="pdf-thumbnail-sidebar" class="pdf-editor-right-panel hidden">
+                    <h4>Page Preview &amp; Editor</h4>
+                    <p class="sidebar-help">Select a PDF to view pages, check to delete, click ↻ to rotate, and use ◀ / ▶ to reorder.</p>
+                    <div id="pdf-thumbnail-grid" class="pdf-thumbnail-grid">
+                        <!-- Page thumbnail cards will be rendered here dynamically -->
+                    </div>
+                </div>
+            </div>
                 <div class="modal-footer">
                     <button id="pdf-editor-cancel" class="btn btn-secondary" data-close>Cancel</button>
                     <button id="pdf-editor-process" class="btn btn-primary">Process</button>

src/main.js

@@ -242,7 +242,9 @@ function runPandoc(args, callback) {
 function runPandocCmd(cmdString, callback) {
   const parsed = parseCommand(cmdString);
   // Skip 'pandoc' if it's the first element (command itself)
-  const args = parsed.command === 'pandoc' ? parsed.args : [parsed.command, ...parsed.args];
+  // Use path.basename to handle full paths like bin/linux/pandoc
+  const cmdBase = path.basename(parsed.command).replace(/\.exe$/i, '');
+  const args = cmdBase === 'pandoc' ? parsed.args : [parsed.command, ...parsed.args];
   const pandocPath = getPandocPath();
   execFile(pandocPath, args, { maxBuffer: 10 * 1024 * 1024 }, callback);
 }
@@ -849,6 +851,20 @@ function createMenu() {
           }
         },
         { type: 'separator' },
+        {
+          label: 'Custom Preview CSS',
+          submenu: [
+            {
+              label: 'Load Custom Preview CSS...',
+              click: () => mainWindow.webContents.send('load-custom-css')
+            },
+            {
+              label: 'Clear Custom Preview CSS',
+              click: () => mainWindow.webContents.send('clear-custom-css')
+            }
+          ]
+        },
+        { type: 'separator' },
         { label: 'Reload', accelerator: 'CmdOrCtrl+R', role: 'reload' },
         { label: 'Toggle DevTools', accelerator: 'F12', role: 'toggleDevTools' },
         { type: 'separator' },
@@ -2297,8 +2313,32 @@ function performExportWithOptions(format, options) {
         dialog.showErrorBox('Export Error', sanitizeErrorMessage(`Failed to export: ${err.message}`));
       }
     } else if (format === 'revealjs') {
-      pandocCmd = `${getPandocPath()} "${currentFile}" -t revealjs -s -o "${outputFile}" --slide-level=2`;
+      let revealCmd = `${getPandocPath()} "${currentFile}" -t revealjs -s -o "${outputFile}" --slide-level=2`;
-      exportWithPandoc(pandocCmd, outputFile, format);
+      if (options) {
+        if (options.revealTheme) revealCmd += ` -V theme="${options.revealTheme}"`;
+        if (options.revealTransition) revealCmd += ` -V transition="${options.revealTransition}"`;
+        if (options.revealTransitionSpeed) revealCmd += ` -V transitionSpeed="${options.revealTransitionSpeed}"`;
+        if (options.revealControls !== undefined) revealCmd += ` -V controls="${options.revealControls}"`;
+        if (options.revealSlideNumber !== undefined) revealCmd += ` -V slideNumber="${options.revealSlideNumber}"`;
+        if (options.revealProgress !== undefined) revealCmd += ` -V progress="${options.revealProgress}"`;
+        if (options.revealHistory !== undefined) revealCmd += ` -V history="${options.revealHistory}"`;
+        if (options.revealCenter !== undefined) revealCmd += ` -V center="${options.revealCenter}"`;
+
+        // Support for templates, metadata, bibliography
+        if (options.template && options.template !== 'default') {
+          revealCmd += ` --template="${options.template}"`;
+        }
+        if (options.metadata) {
+          for (const [key, value] of Object.entries(options.metadata)) {
+            if (value.trim()) {
+              revealCmd += ` -M ${key}="${value.replace(/"/g, '\\"')}"`;
+            }
+          }
+        }
+        if (options.bibliography) revealCmd += ` --bibliography="${options.bibliography}"`;
+        if (options.csl) revealCmd += ` --csl="${options.csl}"`;
+      }
+      exportWithPandoc(revealCmd, outputFile, format);
     } else if (format === 'beamer') {
       pandocCmd = `${getPandocPath()} "${currentFile}" -t beamer -o "${outputFile}"`;
       exportWithPandoc(pandocCmd, outputFile, format);
@@ -2999,6 +3039,55 @@ ipcMain.on('select-folder', (event, type) => {
   }
 });
 
+// List directory contents as FileEntry[]
+ipcMain.handle('list-directory', async (event, dirPath) => {
+  try {
+    const entries = fs.readdirSync(dirPath, { withFileTypes: true });
+    return entries.map((dirent) => {
+      const fullPath = path.join(dirPath, dirent.name);
+      let size;
+      let modifiedAt;
+      if (!dirent.isDirectory()) {
+        try {
+          const stat = fs.statSync(fullPath);
+          size = stat.size;
+          modifiedAt = stat.mtime.toISOString();
+        } catch {
+          // ignore stat errors
+        }
+      }
+      return {
+        name: dirent.name,
+        path: fullPath,
+        isDirectory: dirent.isDirectory(),
+        size,
+        modifiedAt,
+      };
+    });
+  } catch (err) {
+    return { error: err.message };
+  }
+});
+
+// Show folder picker dialog and return selected path or null
+ipcMain.handle('pick-folder', async () => {
+  const result = await dialog.showOpenDialog(mainWindow, {
+    properties: ['openDirectory'],
+  });
+  if (result.canceled || result.filePaths.length === 0) return null;
+  return result.filePaths[0];
+});
+
+// Show file picker dialog for markdown files and return selected path or null
+ipcMain.handle('pick-file', async () => {
+  const result = await dialog.showOpenDialog(mainWindow, {
+    properties: ['openFile'],
+    filters: [{ name: 'Markdown', extensions: ['md', 'markdown', 'mdown', 'mkd'] }],
+  });
+  if (result.canceled || result.filePaths.length === 0) return null;
+  return result.filePaths[0];
+});
+
 ipcMain.on('export-spreadsheet', (event, { content, format }) => {
   const outputFile = dialog.showSaveDialogSync(mainWindow, {
     defaultPath: currentFile.replace(/\.[^/.]+$/, `.${format}`),
@@ -3759,7 +3848,7 @@ app.on('open-file', (event, filePath) => {
 // Handle file opening from command line or file association
 function openFileFromPath(filePath) {
   console.log('[MAIN] openFileFromPath called with:', filePath);
-  console.log('[MAIN] rendererReady:', rendererReady, 'mainWindow exists:', !!mainWindow);
+  console.log('[MAIN] rendererReady:', rendererReady, 'mainWindow exists:', !!mainWindow, 'webContents exists:', !!(mainWindow?.webContents));
   if (fs.existsSync(filePath)) {
     const stats = fs.statSync(filePath);
     if (stats.size > MAX_FILE_SIZE) {
@@ -3769,6 +3858,7 @@ function openFileFromPath(filePath) {
     currentFile = filePath;
     const content = fs.readFileSync(filePath, 'utf-8');
     console.log('[MAIN] File read successfully, content length:', content.length);
+    console.log('[MAIN] About to send file-opened. mainWindow:', !!mainWindow, 'webContents:', !!(mainWindow?.webContents), 'rendererReady:', rendererReady);
     if (mainWindow && mainWindow.webContents && rendererReady) {
       // Send file immediately - renderer-ready means UI is initialized
       console.log('[MAIN] Sending file-opened to renderer');
@@ -3990,6 +4080,25 @@ ipcMain.handle('list-directory', async (event, dirPath) => {
   }
 });
 
+ipcMain.handle('select-custom-css', async (event) => {
+  const result = dialog.showOpenDialogSync(mainWindow, {
+    title: 'Select Custom Preview CSS',
+    properties: ['openFile'],
+    filters: [
+      { name: 'CSS Stylesheets', extensions: ['css'] }
+    ]
+  });
+
+  if (result && result[0]) {
+    const filePath = result[0];
+    const content = fs.readFileSync(filePath, 'utf-8');
+    return { path: filePath, content };
+  }
+  return null;
+});
+
+
+
 ipcMain.handle('read-file', async (event, filePath) => {
   const validation = validatePath(filePath);
   if (!validation.valid || !isPathAccessible(validation.resolved)) {

src/main/PDFOperations.js

@@ -60,13 +60,13 @@ async function pdfSplit(data) {
     const pdf = await PDFDocument.load(pdfBytes);
     const totalPages = pdf.getPageCount();
 
-    let splits = [];
+    const splits = [];
 
     if (data.splitMode === 'pages') {
       const ranges = data.pageRanges.split(',').map(r => r.trim());
       for (let i = 0; i < ranges.length; i++) {
         const range = ranges[i];
-        let pages = [];
+        const pages = [];
 
         if (range.includes('-')) {
           const [start, end] = range.split('-').map(n => parseInt(n.trim()));

src/preload.js

@@ -23,6 +23,7 @@ const ALLOWED_SEND_CHANNELS = [
   'save-recent-files',
   'clear-recent-files',
   'renderer-ready',
+  'select-custom-css',
 
   // Theme
   'get-theme',
@@ -150,6 +151,8 @@ const ALLOWED_RECEIVE_CHANNELS = [
   'get-content-for-save',
   'get-content-for-spreadsheet',
   'recent-files-cleared',
+  'load-custom-css',
+  'clear-custom-css',
 
   // UI toggles
   'toggle-preview',
@@ -234,7 +237,12 @@ const ALLOWED_RECEIVE_CHANNELS = [
   'load-template-menu',
   'toggle-command-palette',
   'toggle-sidebar-panel',
-  'toggle-bottom-panel'
+  'toggle-bottom-panel',
+
+  // File dialog / directory listing
+  'list-directory',
+  'pick-folder',
+  'pick-file'
 ];
 
 /**
@@ -341,7 +349,10 @@ contextBridge.exposeInMainWorld('electronAPI', {
     exists: (filePath) => ipcRenderer.invoke('path-exists', filePath),
     isDirectory: (filePath) => ipcRenderer.invoke('is-directory', filePath),
     copy: (source, destination) => ipcRenderer.invoke('copy-path', { source, destination }),
-    move: (source, destination) => ipcRenderer.invoke('move-path', { source, destination })
+    move: (source, destination) => ipcRenderer.invoke('move-path', { source, destination }),
+    list: (dirPath) => ipcRenderer.invoke('list-directory', dirPath),
+    pickFolder: () => ipcRenderer.invoke('pick-folder'),
+    pickFile: () => ipcRenderer.invoke('pick-file')
   },
 
   // Theme Operations

src/renderer.js

@@ -1,9 +1,20 @@
 /**
  * MarkdownConverter Renderer Process
- * @version 4.4.1
+ * @version 4.4.2
  */
 
 const { ipcRenderer } = require('electron');
+
+// Shim window.electronAPI for main window which uses nodeIntegration
+// without preload script (window.electronAPI is normally set by preload.js).
+if (typeof window !== 'undefined' && !window.electronAPI) {
+    window.electronAPI = {
+        getAppVersion: () => ipcRenderer.invoke('get-app-version'),
+        invoke: (channel, data) => ipcRenderer.invoke(channel, data),
+        on: (channel, callback) => ipcRenderer.on(channel, (event, ...args) => callback(...args))
+    };
+}
+
 const marked = require('marked');
 const { markedHighlight } = require('marked-highlight');
 const createDOMPurify = require('dompurify');
@@ -11,7 +22,13 @@ const DOMPurify = createDOMPurify(window);
 const hljs = require('highlight.js');
 const { createEditor } = require('./editor/codemirror-setup');
 const { undo, redo } = require('@codemirror/commands');
-const { ModalManager } = require('./utils/ModalManager');
+// ModalManager is loaded via <script src="utils/ModalManager.js"> in index.html.
+// It already exists in the global scope — re-declaring with let/const causes
+// SyntaxError: "Identifier 'ModalManager' has already been declared".
+if (typeof ModalManager === 'undefined') {
+    const result = require('./utils/ModalManager');
+    ModalManager = result.ModalManager || result;
+}
 // Lazy-loaded modules — defer heavy imports until first use
 let _SidebarManager, _renderTemplatesPanel, _renderExplorerPanel, _renderGitPanel, _renderSnippetsPanel;
 let _ReplPanel, _CommandPalette, _PrintPreview, _createWelcomeContent;
@@ -102,19 +119,24 @@ marked.use({
         start(src) { return src.match(/^:::(note|warning|tip|danger|info)/m)?.index; },
         tokenizer(src) {
             const match = src.match(/^:::(note|warning|tip|danger|info)\s*\n([\s\S]*?)^:::\s*$/m);
-            if (match) {
+            if (match && match.index === 0) {
+                const admonitionType = match[1];
+                const text = match[2].trim();
+                const tokens = [];
+                this.lexer.blockTokens(text, tokens);
                 return {
                     type: 'admonition',
                     raw: match[0],
-                    admonitionType: match[1],
+                    admonitionType,
-                    text: match[2].trim()
+                    text,
+                    tokens
                 };
             }
         },
         renderer(token) {
             const icons = { note: '\u2139', warning: '\u26A0', tip: '\uD83D\uDCA1', danger: '\uD83D\uDD34', info: '\u2139' };
             const icon = icons[token.admonitionType] || '\u2139';
-            const inner = this.parser.parse(token.text);
+            const inner = this.parser.parse(token.tokens || []);
             return `<div class="admonition admonition-${token.admonitionType}">
                 <div class="admonition-title">${icon} ${token.admonitionType.charAt(0).toUpperCase() + token.admonitionType.slice(1)}</div>
                 <div class="admonition-content">${inner}</div>
@@ -131,8 +153,20 @@ function plantumlEncode(text) {
     return '~h' + hex;
 }
 
+// Scopes user custom CSS by prefixing all selectors to protect application UI
+function scopeCSS(cssText, scopeSelector) {
+    if (!cssText) return '';
+    return cssText.replace(/([^\r\n,{}]+)(,(?=[^}]*{)|(?=[^{]*{))/g, (match, selector, separator) => {
+        const trimmed = selector.trim();
+        if (!trimmed || trimmed.startsWith('@') || trimmed.startsWith(':root') || trimmed.startsWith('from') || trimmed.startsWith('to') || /^\d+%$/.test(trimmed)) {
+            return match;
+        }
+        return scopeSelector + ' ' + trimmed + (separator || '');
+    });
+}
+
 // Module-level reference set by DOMContentLoaded after sidebar registration
-let outlinePanelContainer = null;
+const outlinePanelContainer = null;
 
 // Tab Management
 class TabManager {
@@ -147,6 +181,7 @@ class TabManager {
         this.recentFiles = JSON.parse(localStorage.getItem('recentFiles') || '[]');
         this.previewDebounceTimers = new Map(); // Debounce timers per tab
         this.previewDebounceDelay = 300; // 300ms debounce
+        this.previewCache = new Map(); // Performance optimization render cache
 
         // Initialize first tab
         this.tabs.set(1, {
@@ -230,7 +265,7 @@ class TabManager {
             editorView: null,
             findMatches: [],
             currentMatchIndex: -1,
-            type: type,
+            type: type, // 'markdown' or 'pdf'
             // PDF-specific state
             pdfDoc: null,
             pdfCurrentPage: 1,
@@ -243,6 +278,7 @@ class TabManager {
         this.switchToTab(newTabId);
         this.startAutoSave();
         this.updateTabBar();
+        console.log('createNewTab: tab created with type:', type);
     }
 
     createPdfTab(filePath) {
@@ -454,27 +490,7 @@ class TabManager {
         document.querySelector('.editor-container').appendChild(tabContent);
 
         // Initialize CodeMirror editor
-        const editorContainer = document.getElementById(`editor-cm-${tab.id}`);
+        this.ensureEditor(tab);
-        if (editorContainer) {
-            const isDark = document.body.className.includes('dark');
-            tab.editorView = createEditor(editorContainer, {
-                content: tab.content,
-                onChange: (newContent) => {
-                    tab.content = newContent;
-                    tab.isDirty = true;
-                    this.updatePreview(tab.id);
-                    this.updateWordCount();
-                    this.updateTabBar();
-                    if (outlinePanelContainer?._refreshOutline) outlinePanelContainer._refreshOutline();
-                },
-                onUpdate: (view) => {
-                    this.updateCursorPosition(view);
-                    if (outlinePanelContainer?._setActiveHeading) outlinePanelContainer._setActiveHeading(view.state.doc.lineAt(view.state.selection.main.head).number);
-                },
-                isDark,
-                showLineNumbers: this.showLineNumbers,
-            });
-        }
     }
     
     switchToTab(tabId) {
@@ -660,6 +676,11 @@ class TabManager {
         const tab = this.tabs.get(tabId);
         if (!tab || tab.type === 'pdf') return;
 
+        // Guard against auto-renders in large file mode
+        if (tab.largeFileMode && !immediate) {
+            return;
+        }
+
         // Clear existing debounce timer for this tab
         if (this.previewDebounceTimers.has(tabId)) {
             clearTimeout(this.previewDebounceTimers.get(tabId));
@@ -678,20 +699,55 @@ class TabManager {
         }, this.previewDebounceDelay));
     }
 
+    _hash(str) {
+        if (!str) return 0;
+        let hash = 0;
+        for (let i = 0; i < str.length; i++) {
+            hash = ((hash << 5) - hash) + str.charCodeAt(i);
+            hash |= 0; // Convert to 32bit integer
+        }
+        return hash;
+    }
+
     _renderPreview(tabId) {
         const tab = this.tabs.get(tabId);
         const preview = document.getElementById(`preview-${tabId}`);
+        console.log('[_renderPreview] tabId:', tabId, 'tab exists:', !!tab, 'preview exists:', !!preview, 'content length:', tab?.content?.length);
 
         if (!tab || !preview) return;
 
         try {
             // Check if libraries are available
             if (!marked || !DOMPurify) {
+                console.error('[_renderPreview] Libraries not available:', { marked: !!marked, DOMPurify: !!DOMPurify });
                 preview.innerHTML = '<div class="preview-error"><div class="preview-error-icon">⚠️</div><div class="preview-error-title">Libraries Not Loaded</div><div class="preview-error-message">Required libraries (marked/DOMPurify) could not be loaded. Please check your installation.</div></div>';
                 return;
             }
-            const html = marked.parse(tab.content);
+
-            let sanitizedHtml = DOMPurify.sanitize(html);
+            // Cache lookup
+            const contentHash = this._hash(tab.content);
+            let sanitizedHtml;
+            if (this.previewCache.has(contentHash)) {
+                console.log('[_renderPreview] Cache hit for hash:', contentHash);
+                sanitizedHtml = this.previewCache.get(contentHash);
+            } else {
+                console.log('[_renderPreview] Cache miss. About to call marked.parse, content length:', tab.content.length);
+                const html = marked.parse(tab.content);
+                console.log('[_renderPreview] marked.parse returned type:', typeof html, 'isPromise:', html instanceof Promise);
+                if (html instanceof Promise) {
+                    console.error('[_renderPreview] marked.parse returned a Promise! Need to await it.');
+                    return;
+                }
+                sanitizedHtml = DOMPurify.sanitize(html);
+                console.log('[_renderPreview] DOMPurify.sanitize returned, length:', sanitizedHtml.length);
+
+                // Add to cache and maintain cache size limit (100 entries)
+                this.previewCache.set(contentHash, sanitizedHtml);
+                if (this.previewCache.size > 100) {
+                    const oldestKey = this.previewCache.keys().next().value;
+                    this.previewCache.delete(oldestKey);
+                }
+            }
 
             // TOC generation
             if (sanitizedHtml.includes('[[toc]]') || sanitizedHtml.includes('[TOC]')) {
@@ -1327,10 +1383,22 @@ class TabManager {
         }
     }
     
+    checkForLargeFile(tab, content) {
+        if (content && content.length > 1024 * 1024) { // >1MB
+            tab.largeFileMode = true;
+            this.isPreviewVisible = false;
+            this.updatePreviewVisibility();
+            notifyUser('Large file detected (>1MB). Large File Mode enabled to maintain peak responsiveness. Live preview auto-render is disabled.', 'warning');
+        } else {
+            tab.largeFileMode = false;
+        }
+    }
+
     // File operations
     openFile(filePath, content) {
         console.log('openFile called with:', filePath, 'content length:', content.length);
         let tab = this.tabs.get(this.activeTabId);
+        console.log('openFile tab state before:', { id: tab?.id, hasEditorView: !!tab?.editorView, contentLength: tab?.content?.length, filePath: tab?.filePath, isDirty: tab?.isDirty });
 
         // Handle both forward and back slashes for cross-platform compatibility
         const fileName = filePath.split(/[\\/]/).pop();
@@ -1344,24 +1412,31 @@ class TabManager {
             tab.originalContent = content;
             tab.isDirty = false;
 
+            this.checkForLargeFile(tab, content);
+
             // Update the editor and preview
             this.setEditorContent(this.activeTabId, content);
-            this.updatePreview(this.activeTabId);
+            console.log('openFile after setEditorContent, tab state:', { id: tab.id, hasEditorView: !!tab.editorView, contentLength: tab.content.length });
+            this.updatePreview(this.activeTabId, true); // immediate=true for initial load
             this.updateWordCount();
         } else {
             // Create new tab for the file
             console.log('Creating new tab for file');
             this.createNewTab();
             tab = this.tabs.get(this.activeTabId);
+            console.log('openFile after createNewTab, tab:', { id: tab.id, hasEditorView: !!tab.editorView });
             tab.filePath = filePath;
             tab.title = fileName;
             tab.content = content;
             tab.originalContent = content;
             tab.isDirty = false;
 
+            this.checkForLargeFile(tab, content);
+
             // Set content in the CodeMirror editor
             this.setEditorContent(this.activeTabId, content);
-            this.updatePreview(this.activeTabId);
+            console.log('openFile after setEditorContent, tab state:', { id: tab.id, hasEditorView: !!tab.editorView, contentLength: tab.content.length });
+            this.updatePreview(this.activeTabId, true); // immediate=true for initial load
             this.updateWordCount();
         }
         this.startAutoSave();
@@ -1369,6 +1444,7 @@ class TabManager {
         this.updateTabBar();
         this.updateFilePath();
         this.updateBreadcrumb();
+        this.updateUI(); // Ensure tab content is visible
 
         // Notify main process about current file for exports
         ipcRenderer.send('set-current-file', filePath);
@@ -1385,9 +1461,47 @@ class TabManager {
         return tab?.content || '';
     }
 
+    // Ensure a tab has a CodeMirror editor (lazy creation fallback)
+    ensureEditor(tab) {
+        if (tab.editorView) return true;
+        const editorContainer = document.getElementById(`editor-cm-${tab.id}`);
+        if (!editorContainer) {
+            console.error(`[ensureEditor] editor-cm-${tab.id} not found in DOM`);
+            return false;
+        }
+        try {
+            const isDark = document.body.className.includes('dark');
+            tab.editorView = createEditor(editorContainer, {
+                content: tab.content,
+                onChange: (newContent) => {
+                    tab.content = newContent;
+                    tab.isDirty = true;
+                    this.updatePreview(tab.id);
+                    this.updateWordCount();
+                    this.updateTabBar();
+                    if (outlinePanelContainer?._refreshOutline) outlinePanelContainer._refreshOutline();
+                },
+                onUpdate: (view) => {
+                    this.updateCursorPosition(view);
+                    if (outlinePanelContainer?._setActiveHeading) outlinePanelContainer._setActiveHeading(view.state.doc.lineAt(view.state.selection.main.head).number);
+                },
+                isDark,
+                showLineNumbers: this.showLineNumbers,
+            });
+            console.log(`[ensureEditor] Created editor for tab ${tab.id}`);
+            return true;
+        } catch (err) {
+            console.error(`[ensureEditor] Failed to create editor for tab ${tab.id}:`, err);
+            return false;
+        }
+    }
+
     // Set content in editor
     setEditorContent(tabId, content) {
         const tab = this.tabs.get(tabId);
+        if (!tab?.editorView) {
+            this.ensureEditor(tab);
+        }
         if (tab?.editorView) {
             tab.editorView.dispatch({
                 changes: { from: 0, to: tab.editorView.state.doc.length, insert: content }
@@ -1445,6 +1559,13 @@ let replPanel;
 
 document.addEventListener('DOMContentLoaded', async () => {
     tabManager = new TabManager();
+
+    // Load saved Custom Preview CSS if present
+    const savedCSSContent = localStorage.getItem('customPreviewCSSContent');
+    if (savedCSSContent) {
+        applyCustomPreviewCSS(savedCSSContent);
+    }
+
     const ReplPanel = getReplPanel();
     replPanel = new ReplPanel();
 
@@ -1483,7 +1604,7 @@ document.addEventListener('DOMContentLoaded', async () => {
     // Initialize sidebar
     const SidebarManager = getSidebarManager();
     const sidebarManager = new SidebarManager();
-    let explorerCurrentDir = null;
+    const explorerCurrentDir = null;
 
     sidebarManager.registerPanel('explorer', {
         title: 'Explorer',
@@ -1624,7 +1745,8 @@ document.addEventListener('DOMContentLoaded', async () => {
         const welcomeHtml = getCreateWelcomeContent()(recentFiles, appVersion);
 
         const tab = tabManager.tabs.get(tabManager.activeTabId);
-        if (tab) {
+        // Only show welcome if no file was opened while we were awaiting
+        if (tab && !tab.filePath && tab.content === '') {
             tab.title = 'Welcome';
             tab.content = '';
             const preview = document.getElementById(`preview-${tab.id}`);
@@ -1766,6 +1888,8 @@ document.addEventListener('DOMContentLoaded', async () => {
     commandPalette.register('Insert Image', '', () => tabManager.wrapSelection('![', '](image.jpg)'));
     commandPalette.register('Toggle Zen Mode', 'F11', () => zenMode.toggle());
     commandPalette.register('Writing Analytics', 'Ctrl+Shift+A', () => getShowAnalyticsModal()(tabManager));
+    commandPalette.register('Load Custom Preview CSS', '', triggerLoadCustomCSS);
+    commandPalette.register('Clear Custom Preview CSS', '', triggerClearCustomCSS);
 
     // Keyboard shortcuts
     document.addEventListener('keydown', (e) => {
@@ -1791,27 +1915,9 @@ document.addEventListener('DOMContentLoaded', async () => {
     });
 
     // Initialize CodeMirror for the initial tab (tab 1)
-    const initialEditorContainer = document.getElementById('editor-cm-1');
+    const initialTab = tabManager.tabs.get(1);
-    if (initialEditorContainer) {
+    if (initialTab) {
-        const tab = tabManager.tabs.get(1);
+        tabManager.ensureEditor(initialTab);
-        const isDark = document.body.className.includes('dark');
-        tab.editorView = createEditor(initialEditorContainer, {
-            content: tab.content,
-            onChange: (newContent) => {
-                tab.content = newContent;
-                tab.isDirty = true;
-                tabManager.updatePreview(tab.id);
-                tabManager.updateWordCount();
-                tabManager.updateTabBar();
-                if (outlinePanelContainer?._refreshOutline) outlinePanelContainer._refreshOutline();
-            },
-            onUpdate: (view) => {
-                tabManager.updateCursorPosition(view);
-                if (outlinePanelContainer?._setActiveHeading) outlinePanelContainer._setActiveHeading(view.state.doc.lineAt(view.state.selection.main.head).number);
-            },
-            isDark,
-            showLineNumbers: tabManager.showLineNumbers,
-        });
     }
 
     // Request current theme
@@ -1835,6 +1941,7 @@ document.addEventListener('DOMContentLoaded', async () => {
     }, 30000);
 });
 
+// IPC event listeners
 // IPC event listeners
 ipcRenderer.on('file-new', () => {
     tabManager.createNewTab();
@@ -1842,8 +1949,20 @@ ipcRenderer.on('file-new', () => {
 
 ipcRenderer.on('file-opened', (event, data) => {
     console.log('[RENDERER] file-opened received:', data.path, 'content length:', data.content.length);
+    console.log('[RENDERER] activeTabId before openFile:', tabManager.activeTabId);
+    // Diagnostic: check library state
+    console.log('[RENDERER] Library state:', {
+        marked: typeof marked,
+        DOMPurify: typeof DOMPurify,
+        markedParse: typeof marked?.parse,
+        dompurifySanitize: typeof DOMPurify?.sanitize,
+        tabManagerExists: !!tabManager
+    });
     if (tabManager) {
         tabManager.openFile(data.path, data.content);
+        console.log('[RENDERER] activeTabId after openFile:', tabManager.activeTabId);
+        const tab = tabManager.tabs.get(tabManager.activeTabId);
+        console.log('[RENDERER] tab state:', { id: tab?.id, hasEditorView: !!tab?.editorView, contentLength: tab?.content?.length });
     } else {
         console.error('[RENDERER] tabManager not initialized!');
     }
@@ -1922,6 +2041,49 @@ ipcRenderer.on('redo', () => {
     }
 });
 
+// Custom Preview CSS event handlers and trigger helpers
+function applyCustomPreviewCSS(cssContent) {
+    let styleTag = document.getElementById('custom-preview-style');
+    if (!styleTag) {
+        styleTag = document.createElement('style');
+        styleTag.id = 'custom-preview-style';
+        document.head.appendChild(styleTag);
+    }
+    const scopedCSS = scopeCSS(cssContent, '.preview-content');
+    styleTag.textContent = scopedCSS;
+}
+
+async function triggerLoadCustomCSS() {
+    try {
+        const result = await window.electronAPI.invoke('select-custom-css');
+        if (result) {
+            console.log('[RENDERER] Custom CSS loaded from:', result.path);
+            localStorage.setItem('customPreviewCSSPath', result.path);
+            localStorage.setItem('customPreviewCSSContent', result.content);
+            applyCustomPreviewCSS(result.content);
+            notifyUser('Custom preview stylesheet applied successfully.', 'success');
+        }
+    } catch (err) {
+        console.error('[RENDERER] Error loading custom CSS:', err);
+        notifyUser('Failed to load custom CSS stylesheet.', 'error');
+    }
+}
+
+function triggerClearCustomCSS() {
+    localStorage.removeItem('customPreviewCSSPath');
+    localStorage.removeItem('customPreviewCSSContent');
+    const styleTag = document.getElementById('custom-preview-style');
+    if (styleTag) {
+        styleTag.remove();
+    }
+    notifyUser('Custom preview stylesheet cleared.', 'info');
+}
+
+ipcRenderer.on('load-custom-css', triggerLoadCustomCSS);
+ipcRenderer.on('clear-custom-css', triggerClearCustomCSS);
+
+
+
 // Font size adjustment
 let currentFontSize = parseInt(localStorage.getItem('fontSize')) || 15;
 
@@ -2041,13 +2203,39 @@ function initializeExportForm(format) {
     document.getElementById('export-citeproc').checked = false;
     document.getElementById('export-toc-depth').value = 3;
 
-    // PDF-specific fields
+    // Toggle and reset PDF-specific fields
+    const pdfOnly = document.querySelector('.pdf-only');
+    if (pdfOnly) {
+        pdfOnly.style.display = (format === 'pdf') ? 'block' : 'none';
+    }
     if (format === 'pdf') {
         document.getElementById('pdf-engine').value = 'xelatex';
         document.getElementById('pdf-geometry').value = 'margin=1in';
         document.getElementById('custom-geometry').style.display = 'none';
     }
 
+    // Toggle and reset Reveal.js-specific fields
+    const revealjsOnly = document.querySelector('.revealjs-only');
+    if (revealjsOnly) {
+        revealjsOnly.style.display = (format === 'revealjs') ? 'block' : 'none';
+    }
+    const revealTheme = document.getElementById('reveal-theme');
+    if (revealTheme) revealTheme.value = 'black';
+    const revealTransition = document.getElementById('reveal-transition');
+    if (revealTransition) revealTransition.value = 'slide';
+    const revealSpeed = document.getElementById('reveal-speed');
+    if (revealSpeed) revealSpeed.value = 'default';
+    const revealSlideNumber = document.getElementById('reveal-slide-number');
+    if (revealSlideNumber) revealSlideNumber.checked = false;
+    const revealControls = document.getElementById('reveal-controls');
+    if (revealControls) revealControls.checked = true;
+    const revealProgress = document.getElementById('reveal-progress');
+    if (revealProgress) revealProgress.checked = true;
+    const revealHistory = document.getElementById('reveal-history');
+    if (revealHistory) revealHistory.checked = true;
+    const revealCenter = document.getElementById('reveal-center');
+    if (revealCenter) revealCenter.checked = true;
+
     // Clear bibliography fields
     document.getElementById('bibliography-file').value = '';
     document.getElementById('csl-file').value = '';
@@ -2107,6 +2295,18 @@ function collectExportOptions() {
             }
         }
 
+        // Reveal.js-specific options
+        if (currentExportFormat === 'revealjs') {
+            options.revealTheme = document.getElementById('reveal-theme').value;
+            options.revealTransition = document.getElementById('reveal-transition').value;
+            options.revealTransitionSpeed = document.getElementById('reveal-speed').value;
+            options.revealSlideNumber = document.getElementById('reveal-slide-number').checked;
+            options.revealControls = document.getElementById('reveal-controls').checked;
+            options.revealProgress = document.getElementById('reveal-progress').checked;
+            options.revealHistory = document.getElementById('reveal-history').checked;
+            options.revealCenter = document.getElementById('reveal-center').checked;
+        }
+
         // Bibliography
         const bibFile = document.getElementById('bibliography-file').value.trim();
         const cslFile = document.getElementById('csl-file').value.trim();
@@ -2117,6 +2317,15 @@ function collectExportOptions() {
         if (currentExportFormat === 'pdf') {
             options.pdfEngine = 'xelatex';
             options.geometry = 'margin=1in';
+        } else if (currentExportFormat === 'revealjs') {
+            options.revealTheme = 'black';
+            options.revealTransition = 'slide';
+            options.revealTransitionSpeed = 'default';
+            options.revealSlideNumber = false;
+            options.revealControls = true;
+            options.revealProgress = true;
+            options.revealHistory = true;
+            options.revealCenter = true;
         }
     }
 
@@ -3034,6 +3243,18 @@ function showPDFEditorDialog(operation, openedFilePath = null) {
         section.classList.add('hidden');
     });
 
+    // Hide visual thumbnail sidebar by default
+    const sidebar = document.getElementById('pdf-thumbnail-sidebar');
+    if (sidebar) {
+        sidebar.classList.add('hidden');
+    }
+    const body = document.querySelector('.pdf-editor-body');
+    if (body) {
+        body.classList.remove('side-by-side');
+    }
+    pdfDocInstance = null;
+    pdfPreviewState = { pages: [], filePath: '' };
+
     // Show the appropriate section and set title
     let sectionId, titleText;
     switch (operation) {
@@ -3067,7 +3288,11 @@ function showPDFEditorDialog(operation, openedFilePath = null) {
             titleText = 'Rotate Pages';
             if (openedFilePath) {
                 const rotateInput = document.getElementById('rotate-input-path');
-                if (rotateInput) rotateInput.value = openedFilePath;
+                if (rotateInput) {
+                    rotateInput.value = openedFilePath;
+                    // Trigger thumbnail generation
+                    setTimeout(() => onPDFFileSelected('rotate-input-path', openedFilePath), 50);
+                }
             }
             break;
         case 'delete':
@@ -3075,7 +3300,11 @@ function showPDFEditorDialog(operation, openedFilePath = null) {
             titleText = 'Delete Pages';
             if (openedFilePath) {
                 const deleteInput = document.getElementById('delete-input-path');
-                if (deleteInput) deleteInput.value = openedFilePath;
+                if (deleteInput) {
+                    deleteInput.value = openedFilePath;
+                    // Trigger thumbnail generation
+                    setTimeout(() => onPDFFileSelected('delete-input-path', openedFilePath), 50);
+                }
             }
             break;
         case 'reorder':
@@ -3083,7 +3312,11 @@ function showPDFEditorDialog(operation, openedFilePath = null) {
             titleText = 'Reorder Pages';
             if (openedFilePath) {
                 const reorderInput = document.getElementById('reorder-input-path');
-                if (reorderInput) reorderInput.value = openedFilePath;
+                if (reorderInput) {
+                    reorderInput.value = openedFilePath;
+                    // Trigger thumbnail generation
+                    setTimeout(() => onPDFFileSelected('reorder-input-path', openedFilePath), 50);
+                }
             }
             break;
         case 'watermark':
@@ -3244,6 +3477,7 @@ document.addEventListener('DOMContentLoaded', () => {
                         const file = e.target.files[0];
                         if (file) {
                             document.getElementById(button.inputId).value = file.path;
+                            onPDFFileSelected(button.inputId, file.path);
                         }
                     };
                     input.click();
@@ -3253,6 +3487,7 @@ document.addEventListener('DOMContentLoaded', () => {
                         const file = e.target.files[0];
                         if (file) {
                             document.getElementById(button.inputId).value = file.path;
+                            onPDFFileSelected(button.inputId, file.path);
                         }
                     };
                     input.click();
@@ -3397,7 +3632,7 @@ function showPDFValidationMessage(message, focusSelector = null) {
 // Process PDF Operation
 function processPDFOperation() {
     const operation = currentPDFOperation;
-    let operationData = { operation };
+    const operationData = { operation };
 
     try {
         switch (operation) {
@@ -4187,7 +4422,7 @@ function textToASCII(text, style) {
         lines[i] = '';
     }
 
-    for (let char of upperText) {
+    for (const char of upperText) {
         const charLines = font.chars[char] || font.chars[' '];
         if (charLines) {
             for (let i = 0; i < font.height; i++) {
@@ -4225,7 +4460,7 @@ function createASCIIBox(text, style, padding) {
     }
 
     // Content lines
-    for (let line of lines) {
+    for (const line of lines) {
         const paddedLine = line.padEnd(maxLength, ' ');
         result += chars.v + ' '.repeat(padding) + paddedLine + ' '.repeat(padding) + chars.v + '\n';
     }
@@ -4861,3 +5096,224 @@ ipcRenderer.on('show-video-tool', (event, tool) => {
         { duration: 5000 }
     );
 });
+
+// ============================================
+// PDF EDITOR VISUAL PAGE SIDEBAR HANDLERS
+// ============================================
+let pdfDocInstance = null;
+let pdfPreviewState = { pages: [], filePath: '' };
+
+function onPDFFileSelected(inputId, filePath) {
+    const eligibleInputs = ['rotate-input-path', 'delete-input-path', 'reorder-input-path'];
+    if (!eligibleInputs.includes(inputId)) {
+        return;
+    }
+
+    const sidebar = document.getElementById('pdf-thumbnail-sidebar');
+    if (sidebar) {
+        sidebar.classList.remove('hidden');
+    }
+    const body = document.querySelector('.pdf-editor-body');
+    if (body) {
+        body.classList.add('side-by-side');
+    }
+
+    loadPDFThumbnails(filePath);
+}
+
+async function loadPDFThumbnails(filePath) {
+    const grid = document.getElementById('pdf-thumbnail-grid');
+    if (!grid) return;
+
+    // Reset previous inputs
+    const rotateInput = document.getElementById('rotate-pages');
+    if (rotateInput) rotateInput.value = '';
+    const deleteInput = document.getElementById('delete-pages');
+    if (deleteInput) deleteInput.value = '';
+    const reorderInput = document.getElementById('reorder-pages');
+    if (reorderInput) reorderInput.value = '';
+
+    grid.innerHTML = '<div class="loading-thumbnails">Loading page thumbnails...</div>';
+
+    try {
+        const pdfjs = getPdfjsLib();
+        const loadingTask = pdfjs.getDocument(filePath);
+        pdfDocInstance = await loadingTask.promise;
+
+        pdfPreviewState.filePath = filePath;
+        pdfPreviewState.pages = [];
+
+        for (let i = 1; i <= pdfDocInstance.numPages; i++) {
+            pdfPreviewState.pages.push({
+                originalPageNum: i,
+                rotation: 0,
+                isDeleted: false
+            });
+        }
+
+        renderThumbnailGrid();
+    } catch (err) {
+        console.error('Error loading PDF thumbnails:', err);
+        grid.innerHTML = '<div class="thumbnail-error">Failed to load PDF thumbnails.</div>';
+    }
+}
+
+function renderThumbnailGrid() {
+    const grid = document.getElementById('pdf-thumbnail-grid');
+    if (!grid || !pdfDocInstance) return;
+
+    grid.innerHTML = '';
+
+    pdfPreviewState.pages.forEach((pageInfo, index) => {
+        const card = document.createElement('div');
+        card.className = 'pdf-thumbnail-card';
+        if (pageInfo.isDeleted) {
+            card.classList.add('marked-delete');
+        }
+
+        const heading = document.createElement('div');
+        heading.className = 'pdf-thumbnail-header';
+        heading.innerHTML = `<span class="badge">Page ${pageInfo.originalPageNum}</span>`;
+
+        const canvasContainer = document.createElement('div');
+        canvasContainer.className = 'canvas-container';
+
+        const canvas = document.createElement('canvas');
+        canvas.className = 'pdf-thumbnail-canvas';
+        if (pageInfo.rotation > 0) {
+            canvas.classList.add('rot' + pageInfo.rotation);
+        }
+        canvasContainer.appendChild(canvas);
+
+        // Render thumbnail canvas
+        renderThumbnail(pdfDocInstance, pageInfo.originalPageNum, canvas, pageInfo.rotation);
+
+        const controlsRow = document.createElement('div');
+        controlsRow.className = 'pdf-thumbnail-controls';
+
+        // Rotate Button
+        const rotateBtn = document.createElement('button');
+        rotateBtn.type = 'button';
+        rotateBtn.className = 'btn-rotate-thumbnail';
+        rotateBtn.innerHTML = '↻ Rotate 90°';
+        rotateBtn.addEventListener('click', () => {
+            pageInfo.rotation = (pageInfo.rotation + 90) % 360;
+            canvas.className = 'pdf-thumbnail-canvas';
+            if (pageInfo.rotation > 0) {
+                canvas.classList.add('rot' + pageInfo.rotation);
+            }
+            renderThumbnail(pdfDocInstance, pageInfo.originalPageNum, canvas, pageInfo.rotation);
+            syncRotateInput();
+        });
+
+        // Delete Checkbox
+        const deleteLabel = document.createElement('label');
+        deleteLabel.className = 'delete-thumbnail-checkbox';
+
+        const deleteChk = document.createElement('input');
+        deleteChk.type = 'checkbox';
+        deleteChk.checked = pageInfo.isDeleted;
+        deleteChk.addEventListener('change', (e) => {
+            pageInfo.isDeleted = e.target.checked;
+            card.classList.toggle('marked-delete', pageInfo.isDeleted);
+            syncDeleteInput();
+        });
+        deleteLabel.appendChild(deleteChk);
+        deleteLabel.appendChild(document.createTextNode(' Delete'));
+
+        // Reorder buttons
+        const reorderDiv = document.createElement('div');
+        reorderDiv.className = 'pdf-thumbnail-reorder';
+
+        const leftBtn = document.createElement('button');
+        leftBtn.type = 'button';
+        leftBtn.className = 'btn-reorder-left';
+        leftBtn.innerHTML = '◀';
+        leftBtn.disabled = (index === 0);
+        leftBtn.addEventListener('click', () => {
+            const temp = pdfPreviewState.pages[index];
+            pdfPreviewState.pages[index] = pdfPreviewState.pages[index - 1];
+            pdfPreviewState.pages[index - 1] = temp;
+            renderThumbnailGrid();
+            syncReorderInput();
+        });
+
+        const rightBtn = document.createElement('button');
+        rightBtn.type = 'button';
+        rightBtn.className = 'btn-reorder-right';
+        rightBtn.innerHTML = '▶';
+        rightBtn.disabled = (index === pdfPreviewState.pages.length - 1);
+        rightBtn.addEventListener('click', () => {
+            const temp = pdfPreviewState.pages[index];
+            pdfPreviewState.pages[index] = pdfPreviewState.pages[index + 1];
+            pdfPreviewState.pages[index + 1] = temp;
+            renderThumbnailGrid();
+            syncReorderInput();
+        });
+
+        reorderDiv.appendChild(leftBtn);
+        reorderDiv.appendChild(rightBtn);
+
+        controlsRow.appendChild(rotateBtn);
+        controlsRow.appendChild(deleteLabel);
+        controlsRow.appendChild(reorderDiv);
+
+        card.appendChild(heading);
+        card.appendChild(canvasContainer);
+        card.appendChild(controlsRow);
+
+        grid.appendChild(card);
+    });
+}
+
+async function renderThumbnail(pdfDoc, originalPageNum, canvasElement, rotation) {
+    try {
+        const page = await pdfDoc.getPage(originalPageNum);
+        const ctx = canvasElement.getContext('2d');
+
+        // Render at a fixed width of 100px
+        const unscaledViewport = page.getViewport({ scale: 1, rotation: 0 });
+        const scale = 100 / unscaledViewport.width;
+        const viewport = page.getViewport({ scale: scale, rotation: 0 });
+
+        canvasElement.width = viewport.width;
+        canvasElement.height = viewport.height;
+
+        await page.render({
+            canvasContext: ctx,
+            viewport: viewport
+        }).promise;
+    } catch (err) {
+        console.error('Error rendering page canvas:', err);
+    }
+}
+
+function syncRotateInput() {
+    const rotatedPages = pdfPreviewState.pages
+        .filter(p => p.rotation > 0)
+        .map(p => p.originalPageNum);
+
+    const rotateInput = document.getElementById('rotate-pages');
+    if (rotateInput) {
+        rotateInput.value = rotatedPages.join(', ');
+    }
+}
+
+function syncDeleteInput() {
+    const deletedPages = pdfPreviewState.pages
+        .filter(p => p.isDeleted)
+        .map(p => p.originalPageNum);
+
+    const deleteInput = document.getElementById('delete-pages');
+    if (deleteInput) {
+        deleteInput.value = deletedPages.join(', ');
+    }
+}
+
+function syncReorderInput() {
+    const order = pdfPreviewState.pages.map(p => p.originalPageNum);
+    const reorderInput = document.getElementById('reorder-pages');
+    if (reorderInput) {
+        reorderInput.value = order.join(', ');
+    }
+}

src/renderer/App.tsx

@@ -0,0 +1,16 @@
+import { AppShell } from './components/layout/AppShell';
+import { ModalLayer } from './components/modals/ModalLayer';
+import { Toaster } from './components/ui/sonner';
+import { useWelcomeTrigger } from './hooks/use-welcome-trigger';
+
+function App() {
+  useWelcomeTrigger();
+  return (
+    <>
+      <AppShell />
+      <ModalLayer />
+      <Toaster />
+    </>
+  );
+}
+export default App;

src/renderer/components/editor/CodeMirrorEditor.tsx

@@ -0,0 +1,80 @@
+import { useEffect, useRef } from 'react';
+import { EditorState, Compartment } from '@codemirror/state';
+import { EditorView, keymap, lineNumbers, highlightActiveLine, drawSelection } from '@codemirror/view';
+import { defaultKeymap, history, historyKeymap, indentWithTab } from '@codemirror/commands';
+import { markdown, markdownLanguage } from '@codemirror/lang-markdown';
+import { searchKeymap, highlightSelectionMatches } from '@codemirror/search';
+import { autocompletion, completionKeymap } from '@codemirror/autocomplete';
+import { oneDark } from '@codemirror/theme-one-dark';
+import { useTheme } from 'next-themes';
+import { lightTheme, lightHighlight } from './themes/light';
+import { useEditorStore } from '@/stores/editor-store';
+
+interface Props {
+  bufferId: string;
+  initialContent: string;
+  onChange?: (content: string) => void;
+  onCursorChange?: (line: number, column: number) => void;
+}
+
+export function CodeMirrorEditor({ bufferId, initialContent, onChange, onCursorChange }: Props) {
+  const ref = useRef<HTMLDivElement>(null);
+  const viewRef = useRef<EditorView | null>(null);
+  const themeCompartment = useRef(new Compartment());
+  const { resolvedTheme } = useTheme();
+  const updateContent = useEditorStore((s) => s.updateContent);
+  const setCursor = useEditorStore((s) => s.setCursor);
+
+  useEffect(() => {
+    if (!ref.current) return;
+    const state = EditorState.create({
+      doc: initialContent,
+      extensions: [
+        lineNumbers(),
+        highlightActiveLine(),
+        highlightSelectionMatches(),
+        history(),
+        drawSelection(),
+        markdown({ base: markdownLanguage, codeLanguages: [] }),
+        autocompletion(),
+        keymap.of([...defaultKeymap, ...historyKeymap, ...searchKeymap, ...completionKeymap, indentWithTab]),
+        themeCompartment.current.of(resolvedTheme === 'dark' ? [oneDark] : [lightTheme, lightHighlight]),
+        EditorView.lineWrapping,
+        EditorView.updateListener.of((v) => {
+          if (v.docChanged) {
+            const content = v.state.doc.toString();
+            updateContent(bufferId, content);
+            onChange?.(content);
+          }
+          if (v.selectionSet || v.docChanged) {
+            const head = v.state.selection.main.head;
+            const line = v.state.doc.lineAt(head);
+            const lineNo = line.number;
+            const col = head - line.from + 1;
+            setCursor(bufferId, lineNo, col);
+            onCursorChange?.(lineNo, col);
+          }
+        }),
+      ],
+    });
+    const view = new EditorView({ state, parent: ref.current });
+    viewRef.current = view;
+    return () => {
+      view.destroy();
+      viewRef.current = null;
+    };
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [bufferId]);
+
+  useEffect(() => {
+    const view = viewRef.current;
+    if (!view) return;
+    view.dispatch({
+      effects: themeCompartment.current.reconfigure(
+        resolvedTheme === 'dark' ? [oneDark] : [lightTheme, lightHighlight]
+      ),
+    });
+  }, [resolvedTheme]);
+
+  return <div ref={ref} className="h-full overflow-hidden" />;
+}

src/renderer/components/editor/EditorPane.tsx

@@ -0,0 +1,32 @@
+import { useEffect } from 'react';
+import { CodeMirrorEditor } from './CodeMirrorEditor';
+import { useEditorStore } from '@/stores/editor-store';
+import { usePreviewStore } from '@/stores/preview-store';
+
+export function EditorPane() {
+  const { buffers, activeId } = useEditorStore();
+  const buf = activeId ? buffers.get(activeId) : null;
+  const setPreviewSource = usePreviewStore((s) => s.setSource);
+
+  useEffect(() => {
+    if (buf) setPreviewSource(buf.content);
+  }, [buf?.id, buf?.content, buf, setPreviewSource]);
+
+  if (!buf) {
+    return (
+      <div className="flex h-full items-center justify-center bg-background text-muted-foreground">
+        <p>No file open. Use File → Open to start.</p>
+      </div>
+    );
+  }
+
+  return (
+    <div className="h-full">
+      <CodeMirrorEditor
+        key={buf.id}
+        bufferId={buf.id}
+        initialContent={buf.content}
+      />
+    </div>
+  );
+}

src/renderer/components/editor/themes/light.ts

@@ -0,0 +1,55 @@
+import { EditorView } from '@codemirror/view';
+import { HighlightStyle, syntaxHighlighting } from '@codemirror/language';
+import { tags as t } from '@lezer/highlight';
+
+const colors = {
+  background: '#ffffff',
+  foreground: '#0d0b09',
+  cursor: '#e5461f',
+  selection: 'rgba(229, 70, 31, 0.15)',
+  gutterBackground: '#fafbfc',
+  gutterForeground: '#7a7878',
+  lineHighlight: 'rgba(0, 0, 0, 0.04)',
+};
+
+export const lightTheme = EditorView.theme(
+  {
+    '&': {
+      backgroundColor: colors.background,
+      color: colors.foreground,
+      height: '100%',
+    },
+    '.cm-content': {
+      caretColor: colors.cursor,
+      fontFamily: 'JetBrains Mono, Fira Code, monospace',
+      fontSize: '13.5px',
+    },
+    '.cm-cursor, .cm-dropCursor': { borderLeftColor: colors.cursor },
+    '&.cm-focused .cm-selectionBackground, .cm-selectionBackground, ::selection': {
+      backgroundColor: colors.selection,
+    },
+    '.cm-gutters': {
+      backgroundColor: colors.gutterBackground,
+      color: colors.gutterForeground,
+      border: 'none',
+    },
+    '.cm-activeLine': { backgroundColor: colors.lineHighlight },
+    '.cm-activeLineGutter': { backgroundColor: 'transparent', color: '#e5461f' },
+  },
+  { dark: false }
+);
+
+const highlightStyle = HighlightStyle.define([
+  { tag: t.heading1, color: '#0d0b09', fontWeight: '700' },
+  { tag: t.heading2, color: '#0d0b09', fontWeight: '700' },
+  { tag: t.heading3, color: '#464646', fontWeight: '600' },
+  { tag: t.link, color: '#e5461f', textDecoration: 'underline' },
+  { tag: t.url, color: '#e5461f' },
+  { tag: t.emphasis, fontStyle: 'italic' },
+  { tag: t.strong, fontWeight: '700' },
+  { tag: t.monospace, color: '#c93a18' },
+  { tag: t.list, color: '#0ea5e9' },
+  { tag: t.quote, color: '#7a7878', fontStyle: 'italic' },
+]);
+
+export const lightHighlight = syntaxHighlighting(highlightStyle);

src/renderer/components/layout/AppHeader.tsx

@@ -0,0 +1,70 @@
+import { PanelLeft, PanelRight, Keyboard, Settings, Info } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+import { ThemeToggle } from '@/components/theme-toggle';
+import { useAppStore } from '@/stores/app-store';
+import { useCommandStore } from '@/stores/command-store';
+
+export function AppHeader() {
+  const { sidebarVisible, previewVisible } = useAppStore();
+  const dispatch = useCommandStore((s) => s.dispatch);
+
+  return (
+    <header className="flex h-14 items-center justify-between border-b border-border bg-card/40 px-4 backdrop-blur">
+      <div className="flex items-center gap-3">
+        <div
+          className="h-7 w-7 rounded-md bg-gradient-to-br from-brand to-brand-dark shadow-[var(--shadow-glow-brand)]"
+          aria-label="MarkdownConverter logo"
+        />
+        <h1 className="font-display text-lg font-bold tracking-tight">MarkdownConverter</h1>
+      </div>
+      <div className="flex items-center gap-1">
+        <Button
+          variant="ghost"
+          size="icon"
+          aria-label="Toggle sidebar"
+          aria-pressed={sidebarVisible}
+          data-testid="header-toggle-sidebar"
+          onClick={() => dispatch('view.toggleSidebar')}
+        >
+          <PanelLeft className="h-4 w-4" />
+        </Button>
+        <Button
+          variant="ghost"
+          size="icon"
+          aria-label="Toggle preview"
+          aria-pressed={previewVisible}
+          data-testid="header-toggle-preview"
+          onClick={() => dispatch('view.togglePreview')}
+        >
+          <PanelRight className="h-4 w-4" />
+        </Button>
+        <Button
+          variant="ghost"
+          size="icon"
+          aria-label="Keyboard shortcuts"
+          data-testid="header-shortcuts"
+          onClick={() => dispatch('shortcuts.show')}
+        >
+          <Keyboard className="h-4 w-4" />
+        </Button>
+        <Button
+          variant="ghost"
+          size="icon"
+          aria-label="Settings"
+          onClick={() => dispatch('settings.open')}
+        >
+          <Settings className="h-4 w-4" />
+        </Button>
+        <Button
+          variant="ghost"
+          size="icon"
+          aria-label="About"
+          onClick={() => dispatch('help.about')}
+        >
+          <Info className="h-4 w-4" />
+        </Button>
+        <ThemeToggle />
+      </div>
+    </header>
+  );
+}

src/renderer/components/layout/AppShell.tsx

@@ -0,0 +1,59 @@
+import { AppHeader } from './AppHeader';
+import { TabBar } from './TabBar';
+import { Toolbar } from './Toolbar';
+import { Breadcrumb } from './Breadcrumb';
+import { StatusBar } from './StatusBar';
+import { EditorPane } from '@/components/editor/EditorPane';
+import { PreviewPane } from '@/components/preview/PreviewPane';
+import { Sidebar } from '@/components/sidebar/Sidebar';
+import { useAppStore } from '@/stores/app-store';
+import { ResizablePanelGroup, ResizablePanel, ResizableHandle } from '@/components/ui/resizable';
+import { useFileShortcuts } from '@/hooks/use-file-shortcuts';
+import { useRestoreLastFolder } from '@/hooks/use-restore-last-folder';
+import { useRegisterMenuCommands, useBridgeNativeMenu } from '@/lib/commands/register-menu-commands';
+
+export function AppShell() {
+  useFileShortcuts();
+  useRestoreLastFolder();
+  useRegisterMenuCommands();
+  useBridgeNativeMenu();
+  const { sidebarVisible, previewVisible, paneSizes, setPaneSizes } = useAppStore();
+
+  return (
+    <div className="flex h-screen flex-col bg-background text-foreground">
+      <AppHeader />
+      <TabBar />
+      <Toolbar />
+      <Breadcrumb />
+      <main className="flex-1 overflow-hidden">
+        <ResizablePanelGroup
+          direction="horizontal"
+          onLayout={(sizes) => setPaneSizes({ sidebar: sizes[0], editor: sizes[1], preview: sizes[2] })}
+        >
+          {sidebarVisible && (
+            <>
+              <ResizablePanel defaultSize={paneSizes.sidebar} minSize={15} maxSize={40}>
+                <aside className="h-full border-r border-border bg-card/10 p-3 text-sm text-muted-foreground">
+                  <Sidebar />
+                </aside>
+              </ResizablePanel>
+              <ResizableHandle />
+            </>
+          )}
+          <ResizablePanel defaultSize={previewVisible ? paneSizes.editor : 100} minSize={20}>
+            <EditorPane />
+          </ResizablePanel>
+          {previewVisible && (
+            <>
+              <ResizableHandle />
+              <ResizablePanel defaultSize={paneSizes.preview} minSize={20}>
+                <PreviewPane />
+              </ResizablePanel>
+            </>
+          )}
+        </ResizablePanelGroup>
+      </main>
+      <StatusBar />
+    </div>
+  );
+}

src/renderer/components/layout/Breadcrumb.tsx

@@ -0,0 +1,7 @@
+export function Breadcrumb() {
+  return (
+    <nav aria-label="File path" className="flex h-7 items-center border-b border-border bg-card/10 px-3 text-xs text-muted-foreground">
+      <span>No file selected</span>
+    </nav>
+  );
+}

src/renderer/components/layout/StatusBar.tsx

@@ -0,0 +1,25 @@
+import { useEditorStore } from '@/stores/editor-store';
+
+function countWords(text: string): number {
+  return text.trim().length === 0 ? 0 : text.trim().split(/\s+/).length;
+}
+
+export function StatusBar() {
+  const { buffers, activeId } = useEditorStore();
+  const buf = activeId ? buffers.get(activeId) : null;
+  const wordCount = buf ? countWords(buf.content) : 0;
+  const cursor = buf?.cursor ?? { line: 1, column: 1 };
+
+  return (
+    <footer className="flex h-7 items-center justify-between border-t border-border bg-card/20 px-3 text-xs text-muted-foreground">
+      <div className="flex items-center gap-4">
+        <span>{wordCount} words</span>
+        <span>UTF-8</span>
+      </div>
+      <div className="flex items-center gap-4">
+        <span>Ln {cursor.line}, Col {cursor.column}</span>
+        <span>Markdown</span>
+      </div>
+    </footer>
+  );
+}

src/renderer/components/layout/TabBar.tsx

@@ -0,0 +1,127 @@
+import { X } from 'lucide-react';
+import {
+  DndContext,
+  PointerSensor,
+  useSensor,
+  useSensors,
+  closestCenter,
+  type DragEndEvent,
+} from '@dnd-kit/core';
+import {
+  SortableContext,
+  horizontalListSortingStrategy,
+  useSortable,
+} from '@dnd-kit/sortable';
+import { CSS } from '@dnd-kit/utilities';
+import { useFileStore, type OpenTab } from '@/stores/file-store';
+import { cn } from '@/lib/utils';
+
+function SortableTab({
+  tab,
+  isActive,
+  onSelect,
+  onClose,
+}: {
+  tab: OpenTab;
+  isActive: boolean;
+  onSelect: (id: string) => void;
+  onClose: (id: string) => void;
+}) {
+  const { attributes, listeners, setNodeRef, transform, transition, isDragging } = useSortable({
+    id: tab.id,
+  });
+
+  const style = {
+    transform: CSS.Transform.toString(transform),
+    transition,
+    opacity: isDragging ? 0.5 : 1,
+  };
+
+  return (
+    <div
+      ref={setNodeRef}
+      style={style}
+      {...attributes}
+      {...listeners}
+      role="tab"
+      aria-selected={isActive}
+      aria-current={isActive ? 'page' : undefined}
+      data-testid={`tab-${tab.id}`}
+      className={cn(
+        'group flex h-full cursor-pointer select-none items-center gap-1 border-r border-border px-3 text-xs transition-colors',
+        isActive
+          ? 'bg-accent text-accent-foreground'
+          : 'text-muted-foreground hover:bg-muted/50 hover:text-foreground'
+      )}
+      onClick={() => onSelect(tab.id)}
+    >
+      {tab.dirty && (
+        <span
+          className="h-1.5 w-1.5 shrink-0 rounded-full bg-primary"
+          aria-label="Unsaved changes"
+        />
+      )}
+      <span className="max-w-[120px] truncate">{tab.title}</span>
+      <button
+        aria-label={`Close ${tab.title}`}
+        className="ml-1 flex h-4 w-4 shrink-0 items-center justify-center rounded opacity-0 group-hover:opacity-100 hover:bg-muted-foreground/20 transition-opacity"
+        onPointerDown={(e) => e.stopPropagation()}
+        onClick={(e) => {
+          e.stopPropagation();
+          onClose(tab.id);
+        }}
+      >
+        <X className="h-3 w-3" />
+      </button>
+    </div>
+  );
+}
+
+export function TabBar() {
+  const openTabs = useFileStore((s) => s.openTabs);
+  const activeTabId = useFileStore((s) => s.activeTabId);
+  const setActiveTab = useFileStore((s) => s.setActiveTab);
+  const closeTab = useFileStore((s) => s.closeTab);
+  const reorderTabs = useFileStore((s) => s.reorderTabs);
+
+  // Require a small drag distance before activating — so a click on the tab
+  // body still triggers `onClick` (dnd-kit's PointerSensor default is 0).
+  const sensors = useSensors(useSensor(PointerSensor, { activationConstraint: { distance: 6 } }));
+
+  if (openTabs.length === 0) {
+    return (
+      <div className="flex h-9 items-center border-b border-border bg-card/20 px-3 text-xs text-muted-foreground">
+        <span>No files open</span>
+      </div>
+    );
+  }
+
+  function handleDragEnd(e: DragEndEvent) {
+    const { active, over } = e;
+    if (!over || active.id === over.id) return;
+    const fromIndex = openTabs.findIndex((t) => t.id === active.id);
+    const toIndex = openTabs.findIndex((t) => t.id === over.id);
+    if (fromIndex === -1 || toIndex === -1) return;
+    reorderTabs(fromIndex, toIndex);
+  }
+
+  return (
+    <div className="flex h-9 items-center border-b border-border bg-card/20 overflow-x-auto">
+      <DndContext sensors={sensors} collisionDetection={closestCenter} onDragEnd={handleDragEnd}>
+        <SortableContext items={openTabs.map((t) => t.id)} strategy={horizontalListSortingStrategy}>
+          <div className="flex h-full items-center px-1">
+            {openTabs.map((tab) => (
+              <SortableTab
+                key={tab.id}
+                tab={tab}
+                isActive={tab.id === activeTabId}
+                onSelect={setActiveTab}
+                onClose={closeTab}
+              />
+            ))}
+          </div>
+        </SortableContext>
+      </DndContext>
+    </div>
+  );
+}

src/renderer/components/layout/Toolbar.tsx

@@ -0,0 +1,77 @@
+import { Bold, Italic, List, ListOrdered, Code, Link as LinkIcon, PanelLeft, PanelRight, Save, FolderOpen, FileText } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+import { useCommandStore } from '@/stores/command-store';
+import { useAppStore } from '@/stores/app-store';
+
+export function Toolbar() {
+  const dispatch = useCommandStore((s) => s.dispatch);
+  const { sidebarVisible, previewVisible } = useAppStore();
+
+  return (
+    <div
+      role="toolbar"
+      aria-label="Main toolbar"
+      className="flex h-10 items-center gap-1 border-b border-border bg-card/10 px-3"
+    >
+      <Button
+        variant="ghost"
+        size="icon"
+        aria-label="Open file"
+        data-testid="toolbar-open-file"
+        onClick={() => dispatch('file.open')}
+      >
+        <FileText className="h-4 w-4" />
+      </Button>
+      <Button
+        variant="ghost"
+        size="icon"
+        aria-label="Open folder"
+        data-testid="toolbar-open-folder"
+        onClick={() => dispatch('file.openFolder')}
+      >
+        <FolderOpen className="h-4 w-4" />
+      </Button>
+      <Button
+        variant="ghost"
+        size="icon"
+        aria-label="Save"
+        data-testid="toolbar-save"
+        onClick={() => dispatch('file.save')}
+      >
+        <Save className="h-4 w-4" />
+      </Button>
+
+      <div className="mx-1 h-5 w-px bg-border" aria-hidden="true" />
+
+      <Button
+        variant="ghost"
+        size="icon"
+        aria-label="Toggle sidebar"
+        aria-pressed={sidebarVisible}
+        data-testid="toolbar-toggle-sidebar"
+        onClick={() => dispatch('view.toggleSidebar')}
+      >
+        <PanelLeft className="h-4 w-4" />
+      </Button>
+      <Button
+        variant="ghost"
+        size="icon"
+        aria-label="Toggle preview"
+        aria-pressed={previewVisible}
+        data-testid="toolbar-toggle-preview"
+        onClick={() => dispatch('view.togglePreview')}
+      >
+        <PanelRight className="h-4 w-4" />
+      </Button>
+
+      <div className="mx-1 h-5 w-px bg-border" aria-hidden="true" />
+
+      <Button variant="ghost" size="icon" aria-label="Bold" disabled><Bold className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Italic" disabled><Italic className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Unordered list" disabled><List className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Ordered list" disabled><ListOrdered className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Code" disabled><Code className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Link" disabled><LinkIcon className="h-4 w-4" /></Button>
+    </div>
+  );
+}

src/renderer/components/modals/AboutDialog.tsx

@@ -0,0 +1,49 @@
+import { useEffect, useState } from 'react';
+import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle } from '@/components/ui/dialog';
+import { Button } from '@/components/ui/button';
+import { ipc } from '@/lib/ipc';
+import { useAppStore } from '@/stores/app-store';
+
+export function AboutDialog() {
+  const closeModal = useAppStore((s) => s.closeModal);
+  const isOpen = useAppStore((s) => s.modal.kind) === 'about';
+  const [version, setVersion] = useState<string>('…');
+
+  useEffect(() => {
+    ipc.app.getVersion().then((r) => {
+      if (r.ok && typeof r.data === 'string') setVersion(r.data);
+    });
+  }, []);
+
+  return (
+    <Dialog open={isOpen} onOpenChange={(o) => !o && closeModal()}>
+      <DialogContent aria-describedby="about-desc">
+        <DialogHeader>
+          <DialogTitle>About MarkdownConverter</DialogTitle>
+          <DialogDescription id="about-desc">
+            Professional Markdown editor and universal file converter.
+          </DialogDescription>
+        </DialogHeader>
+        <div className="space-y-2 text-sm text-muted-foreground">
+          <p>Version: {version}</p>
+          <p>
+            <a
+              href="https://github.com/amitwh/markdown-converter"
+              className="text-brand hover:underline"
+              onClick={(e) => {
+                e.preventDefault();
+                ipc.app.openExternal('https://github.com/amitwh/markdown-converter');
+              }}
+            >
+              GitHub repository
+            </a>
+          </p>
+          <p className="text-xs">© ConcreteInfo. Licensed under MIT.</p>
+        </div>
+        <DialogFooter>
+          <Button onClick={closeModal}>Close</Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  );
+}

src/renderer/components/modals/AboutSettings.tsx

@@ -0,0 +1,38 @@
+import { useEffect, useState } from 'react';
+import { ipc } from '@/lib/ipc';
+
+export function AboutSettings() {
+  const [version, setVersion] = useState('…');
+
+  useEffect(() => {
+    ipc.app.getVersion().then((r) => {
+      if (r.ok && typeof r.data === 'string') setVersion(r.data);
+    });
+  }, []);
+
+  return (
+    <div className="space-y-3 text-sm">
+      <h3 className="text-base font-semibold">MarkdownConverter</h3>
+      <p className="text-muted-foreground">Version {version}</p>
+      <p>
+        <a
+          href="https://github.com/amitwh/markdown-converter"
+          className="text-brand hover:underline"
+          onClick={(e) => { e.preventDefault(); ipc.app.openExternal('https://github.com/amitwh/markdown-converter'); }}
+        >
+          GitHub repository
+        </a>
+      </p>
+      <p>
+        <a
+          href="https://concreteinfo.co.in"
+          className="text-brand hover:underline"
+          onClick={(e) => { e.preventDefault(); ipc.app.openExternal('https://concreteinfo.co.in'); }}
+        >
+          ConcreteInfo
+        </a>
+      </p>
+      <p className="text-xs text-muted-foreground">© ConcreteInfo. Licensed under MIT.</p>
+    </div>
+  );
+}

src/renderer/components/modals/ConfirmDialog.tsx

@@ -0,0 +1,36 @@
+import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle } from '@/components/ui/dialog';
+import { Button } from '@/components/ui/button';
+import { useAppStore, type ConfirmProps } from '@/stores/app-store';
+
+export function ConfirmDialog(props: ConfirmProps) {
+  const closeModal = useAppStore((s) => s.closeModal);
+  const { title, body, confirmLabel = 'Confirm', cancelLabel = 'Cancel', destructive, onConfirm, onCancel } = props;
+
+  const handleConfirm = async () => {
+    await onConfirm();
+    closeModal();
+  };
+  const handleCancel = () => {
+    onCancel?.();
+    closeModal();
+  };
+
+  return (
+    <Dialog open onOpenChange={(o) => !o && handleCancel()}>
+      <DialogContent aria-describedby="confirm-body">
+        <DialogHeader>
+          <DialogTitle>{title}</DialogTitle>
+          <DialogDescription id="confirm-body">{body}</DialogDescription>
+        </DialogHeader>
+        <DialogFooter>
+          <Button variant="ghost" onClick={handleCancel}>
+            {cancelLabel}
+          </Button>
+          <Button variant={destructive ? 'destructive' : 'default'} onClick={handleConfirm}>
+            {confirmLabel}
+          </Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  );
+}

src/renderer/components/modals/EditorSettings.tsx

@@ -0,0 +1,41 @@
+import { useSettingsStore } from '@/stores/settings-store';
+import { Label } from '@/components/ui/label';
+import { Slider } from '@/components/ui/slider';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+import { Switch } from '@/components/ui/switch';
+
+export function EditorSettings() {
+  const { fontSize, tabSize, lineNumbers, wordWrap, minimap, setSetting } = useSettingsStore();
+
+  return (
+    <div className="space-y-5 text-sm">
+      <div>
+        <Label htmlFor="editor-font-size">Font size: {fontSize}px</Label>
+        <Slider id="editor-font-size" min={10} max={24} step={1} value={[fontSize]} onValueChange={([v]) => setSetting('fontSize', v)} />
+      </div>
+      <div>
+        <Label htmlFor="editor-tab-size">Tab size</Label>
+        <Select value={String(tabSize)} onValueChange={(v) => setSetting('tabSize', Number(v) as 2 | 4 | 8)}>
+          <SelectTrigger id="editor-tab-size" aria-label="Tab size"><SelectValue /></SelectTrigger>
+          <SelectContent>
+            <SelectItem value="2">2 spaces</SelectItem>
+            <SelectItem value="4">4 spaces</SelectItem>
+            <SelectItem value="8">8 spaces</SelectItem>
+          </SelectContent>
+        </Select>
+      </div>
+      <label className="flex items-center justify-between">
+        <span>Line numbers</span>
+        <Switch checked={lineNumbers} onCheckedChange={(c) => setSetting('lineNumbers', c)} aria-label="Line numbers" />
+      </label>
+      <label className="flex items-center justify-between">
+        <span>Word wrap</span>
+        <Switch checked={wordWrap} onCheckedChange={(c) => setSetting('wordWrap', c)} aria-label="Word wrap" />
+      </label>
+      <label className="flex items-center justify-between">
+        <span>Minimap</span>
+        <Switch checked={minimap} onCheckedChange={(c) => setSetting('minimap', c)} aria-label="Minimap" />
+      </label>
+    </div>
+  );
+}

src/renderer/components/modals/ExportBatchDialog.tsx

@@ -0,0 +1,82 @@
+import { useState } from 'react';
+import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle } from '@/components/ui/dialog';
+import { Label } from '@/components/ui/label';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+import { useAppStore } from '@/stores/app-store';
+import { ipc } from '@/lib/ipc';
+import { toast } from '@/lib/toast';
+import { ExportDialogFooter } from './ExportDialogFooter';
+
+const extFor = (format: 'pdf' | 'docx' | 'html' | 'png') =>
+  format === 'pdf' ? '.pdf' : format === 'docx' ? '.docx' : format === 'png' ? '.png' : '.html';
+
+export function ExportBatchDialog({ sourcePaths }: { sourcePaths: string[] }) {
+  const closeModal = useAppStore((s) => s.closeModal);
+  const [format, setFormat] = useState<'pdf' | 'docx' | 'html' | 'png'>('pdf');
+  const [concurrency, setConcurrency] = useState(4);
+  const [submitting, setSubmitting] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const handleSubmit = async () => {
+    setSubmitting(true);
+    setError(null);
+    const items = sourcePaths.map((p) => ({
+      inputPath: p,
+      outputPath: p.replace(/\.md$/, extFor(format)),
+    }));
+    const result = await ipc.export.batch(items, { format, concurrency });
+    if (!result.ok) {
+      toast.error(`Export failed: ${result.error.message}`);
+      setError(result.error.message);
+      setSubmitting(false);
+    } else {
+      toast.success(`Exported ${sourcePaths.length} files`);
+      closeModal();
+    }
+  };
+
+  return (
+    <Dialog open onOpenChange={(o) => !o && closeModal()}>
+      <DialogContent aria-describedby="batch-desc">
+        <DialogHeader>
+          <DialogTitle>Batch export</DialogTitle>
+          <DialogDescription id="batch-desc">{sourcePaths.length} files</DialogDescription>
+        </DialogHeader>
+        <div className="space-y-3 text-sm">
+          <div>
+            <Label htmlFor="batch-format">Format</Label>
+            <Select value={format} onValueChange={(v) => setFormat(v as any)}>
+              <SelectTrigger id="batch-format" aria-label="Format"><SelectValue /></SelectTrigger>
+              <SelectContent>
+                <SelectItem value="pdf">PDF</SelectItem>
+                <SelectItem value="docx">DOCX</SelectItem>
+                <SelectItem value="html">HTML</SelectItem>
+                <SelectItem value="png">PNG</SelectItem>
+              </SelectContent>
+            </Select>
+          </div>
+          <div>
+            <Label htmlFor="batch-concurrency">Concurrency</Label>
+            <Select value={String(concurrency)} onValueChange={(v) => setConcurrency(Number(v))}>
+              <SelectTrigger id="batch-concurrency" aria-label="Concurrency"><SelectValue /></SelectTrigger>
+              <SelectContent>
+                {[1, 2, 4, 8, 16].map((n) => (
+                  <SelectItem key={n} value={String(n)}>{n}</SelectItem>
+                ))}
+              </SelectContent>
+            </Select>
+          </div>
+          <div className="max-h-40 overflow-auto rounded border border-border bg-card/20 p-2 text-xs">
+            {sourcePaths.map((p) => <div key={p} className="truncate">{p}</div>)}
+          </div>
+          {error && (
+            <div role="alert" className="rounded border border-destructive/40 bg-destructive/5 p-2 text-xs text-destructive">
+              {error}
+            </div>
+          )}
+        </div>
+        <ExportDialogFooter onCancel={closeModal} onSubmit={handleSubmit} submitting={submitting} submitLabel="Export" />
+      </DialogContent>
+    </Dialog>
+  );
+}

src/renderer/components/modals/ExportDialogFooter.tsx

@@ -0,0 +1,23 @@
+import { Button } from '@/components/ui/button';
+import { DialogFooter } from '@/components/ui/dialog';
+
+interface Props {
+  onCancel: () => void;
+  onSubmit: () => void;
+  submitting: boolean;
+  submitLabel: string;
+  submitDisabled?: boolean;
+}
+
+export function ExportDialogFooter({ onCancel, onSubmit, submitting, submitLabel, submitDisabled }: Props) {
+  return (
+    <DialogFooter>
+      <Button variant="ghost" onClick={onCancel} disabled={submitting}>
+        Cancel
+      </Button>
+      <Button onClick={onSubmit} disabled={submitting || submitDisabled}>
+        {submitting ? 'Exporting…' : submitLabel}
+      </Button>
+    </DialogFooter>
+  );
+}

src/renderer/components/modals/ExportDocxDialog.tsx

@@ -0,0 +1,78 @@
+import { useState } from 'react';
+import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle } from '@/components/ui/dialog';
+import { Checkbox } from '@/components/ui/checkbox';
+import { Label } from '@/components/ui/label';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+import { useAppStore } from '@/stores/app-store';
+import { useSettingsStore } from '@/stores/settings-store';
+import { useExportSource } from '@/hooks/use-export-source';
+import { ipc } from '@/lib/ipc';
+import { toast } from '@/lib/toast';
+import { ExportDialogFooter } from './ExportDialogFooter';
+
+export function ExportDocxDialog({ sourcePath }: { sourcePath: string }) {
+  const closeModal = useAppStore((s) => s.closeModal);
+  const { docxTemplate, renderTablesAsAscii } = useSettingsStore();
+  const source = useExportSource();
+  const [template, setTemplate] = useState<'standard' | 'minimal' | 'modern'>(docxTemplate);
+  const [ascii, setAscii] = useState(renderTablesAsAscii);
+  const [submitting, setSubmitting] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const handleSubmit = async () => {
+    if (!source) { setError('No file open.'); return; }
+    setSubmitting(true);
+    setError(null);
+    const result = await ipc.export.docx({
+      inputPath: source.path,
+      outputPath: source.path.replace(/\.md$/, '.docx'),
+      template,
+      renderTablesAsAscii: ascii,
+    } as any);
+    if (!result.ok) {
+      toast.error(`Export failed: ${result.error.message}`);
+      setError(result.error.message);
+      setSubmitting(false);
+    } else {
+      toast.success(`Exported ${source.title} to ${result.data?.outputPath ?? 'file'}`);
+      closeModal();
+    }
+  };
+
+  return (
+    <Dialog open onOpenChange={(o) => !o && closeModal()}>
+      <DialogContent aria-describedby="docx-desc">
+        <DialogHeader>
+          <DialogTitle>Export to DOCX</DialogTitle>
+          <DialogDescription id="docx-desc">{sourcePath}</DialogDescription>
+        </DialogHeader>
+        <div className="space-y-3 text-sm">
+          <div>
+            <Label htmlFor="docx-template">Template</Label>
+            <Select value={template} onValueChange={(v) => setTemplate(v as any)}>
+              <SelectTrigger id="docx-template" aria-label="Template"><SelectValue /></SelectTrigger>
+              <SelectContent>
+                <SelectItem value="standard">Standard</SelectItem>
+                <SelectItem value="minimal">Minimal</SelectItem>
+                <SelectItem value="modern">Modern</SelectItem>
+              </SelectContent>
+            </Select>
+            <p className="mt-1 text-xs text-muted-foreground">
+              Bundled with the app. Standard is the default; Modern adds a colored cover page.
+            </p>
+          </div>
+          <label className="flex items-center gap-2">
+            <Checkbox checked={ascii} onCheckedChange={(c) => setAscii(!!c)} aria-label="ASCII tables" />
+            Render tables as ASCII
+          </label>
+          {error && (
+            <div role="alert" className="rounded border border-destructive/40 bg-destructive/5 p-2 text-xs text-destructive">
+              {error}
+            </div>
+          )}
+        </div>
+        <ExportDialogFooter onCancel={closeModal} onSubmit={handleSubmit} submitting={submitting} submitLabel="Export" />
+      </DialogContent>
+    </Dialog>
+  );
+}

src/renderer/components/modals/ExportHtmlDialog.tsx

@@ -0,0 +1,82 @@
+import { useState } from 'react';
+import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle } from '@/components/ui/dialog';
+import { Checkbox } from '@/components/ui/checkbox';
+import { Label } from '@/components/ui/label';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+import { useAppStore } from '@/stores/app-store';
+import { useSettingsStore } from '@/stores/settings-store';
+import { useExportSource } from '@/hooks/use-export-source';
+import { ipc } from '@/lib/ipc';
+import { toast } from '@/lib/toast';
+import { ExportDialogFooter } from './ExportDialogFooter';
+
+export function ExportHtmlDialog({ sourcePath }: { sourcePath: string }) {
+  const closeModal = useAppStore((s) => s.closeModal);
+  const { htmlHighlightStyle, renderTablesAsAscii } = useSettingsStore();
+  const source = useExportSource();
+  const [standalone, setStandalone] = useState(true);
+  const [highlight, setHighlight] = useState(htmlHighlightStyle);
+  const [ascii, setAscii] = useState(renderTablesAsAscii);
+  const [submitting, setSubmitting] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const handleSubmit = async () => {
+    if (!source) { setError('No file open.'); return; }
+    setSubmitting(true);
+    setError(null);
+    const result = await ipc.export.html({
+      inputPath: source.path,
+      outputPath: source.path.replace(/\.md$/, '.html'),
+      standalone,
+      highlightStyle: highlight,
+      renderTablesAsAscii: ascii,
+    } as any);
+    if (!result.ok) {
+      toast.error(`Export failed: ${result.error.message}`);
+      setError(result.error.message);
+      setSubmitting(false);
+    } else {
+      toast.success(`Exported ${source.title} to ${result.data?.outputPath ?? 'file'}`);
+      closeModal();
+    }
+  };
+
+  return (
+    <Dialog open onOpenChange={(o) => !o && closeModal()}>
+      <DialogContent aria-describedby="html-desc">
+        <DialogHeader>
+          <DialogTitle>Export to HTML</DialogTitle>
+          <DialogDescription id="html-desc">{sourcePath}</DialogDescription>
+        </DialogHeader>
+        <div className="space-y-3 text-sm">
+          <label className="flex items-center gap-2">
+            <Checkbox checked={standalone} onCheckedChange={(c) => setStandalone(!!c)} aria-label="Standalone" />
+            Standalone document (with inline CSS)
+          </label>
+          <div>
+            <Label htmlFor="html-highlight">Syntax highlight style</Label>
+            <Select value={highlight} onValueChange={(v) => setHighlight(v as any)}>
+              <SelectTrigger id="html-highlight" aria-label="Highlight style"><SelectValue /></SelectTrigger>
+              <SelectContent>
+                <SelectItem value="github">GitHub</SelectItem>
+                <SelectItem value="monokai">Monokai</SelectItem>
+                <SelectItem value="nord">Nord</SelectItem>
+                <SelectItem value="none">None</SelectItem>
+              </SelectContent>
+            </Select>
+          </div>
+          <label className="flex items-center gap-2">
+            <Checkbox checked={ascii} onCheckedChange={(c) => setAscii(!!c)} aria-label="ASCII tables" />
+            Render tables as ASCII
+          </label>
+          {error && (
+            <div role="alert" className="rounded border border-destructive/40 bg-destructive/5 p-2 text-xs text-destructive">
+              {error}
+            </div>
+          )}
+        </div>
+        <ExportDialogFooter onCancel={closeModal} onSubmit={handleSubmit} submitting={submitting} submitLabel="Export" />
+      </DialogContent>
+    </Dialog>
+  );
+}

src/renderer/components/modals/ExportPdfDialog.tsx

@@ -0,0 +1,105 @@
+import { useState } from 'react';
+import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle } from '@/components/ui/dialog';
+import { Checkbox } from '@/components/ui/checkbox';
+import { Label } from '@/components/ui/label';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+import { useAppStore } from '@/stores/app-store';
+import { useSettingsStore } from '@/stores/settings-store';
+import { useExportSource } from '@/hooks/use-export-source';
+import { ipc } from '@/lib/ipc';
+import { toast } from '@/lib/toast';
+import { ExportDialogFooter } from './ExportDialogFooter';
+
+const MARGIN_MAP = {
+  normal: { top: 25, right: 25, bottom: 25, left: 25 },
+  narrow: { top: 15, right: 15, bottom: 15, left: 15 },
+  wide: { top: 35, right: 35, bottom: 35, left: 35 },
+} as const;
+
+export function ExportPdfDialog({ sourcePath }: { sourcePath: string }) {
+  const closeModal = useAppStore((s) => s.closeModal);
+  const { fontSize, pdfFormat, pdfMargins, pdfEmbedFonts, renderTablesAsAscii } = useSettingsStore();
+  const [format, setFormat] = useState<'letter' | 'a4' | 'legal'>(pdfFormat);
+  const [margins, setMargins] = useState<'normal' | 'narrow' | 'wide'>(pdfMargins);
+  const [embed, setEmbed] = useState(pdfEmbedFonts);
+  const [ascii, setAscii] = useState(renderTablesAsAscii);
+  const [submitting, setSubmitting] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const source = useExportSource();
+
+  const handleSubmit = async () => {
+    if (!source) {
+      setError('No file open.');
+      return;
+    }
+    setSubmitting(true);
+    setError(null);
+    const result = await ipc.export.pdf({
+      inputPath: source.path,
+      outputPath: source.path.replace(/\.md$/, '.pdf'),
+      format,
+      margins: MARGIN_MAP[margins],
+      embedFonts: embed,
+      renderTablesAsAscii: ascii,
+      fontSize,
+    } as any);
+    if (!result.ok) {
+      toast.error(`Export failed: ${result.error?.message ?? 'Export failed'}`);
+      setError(result.error?.message ?? 'Export failed');
+      setSubmitting(false);
+    } else {
+      toast.success(`Exported ${source.title} to ${result.data?.outputPath ?? 'file'}`);
+      closeModal();
+    }
+  };
+
+  return (
+    <Dialog open onOpenChange={(o) => !o && closeModal()}>
+      <DialogContent aria-describedby="pdf-desc">
+        <DialogHeader>
+          <DialogTitle>Export to PDF</DialogTitle>
+          <DialogDescription id="pdf-desc">{sourcePath}</DialogDescription>
+        </DialogHeader>
+        <div className="space-y-3 text-sm">
+          <div>
+            <Label htmlFor="pdf-format">Format</Label>
+            <Select value={format} onValueChange={(v) => setFormat(v as typeof format)}>
+              <SelectTrigger id="pdf-format" aria-label="Format"><SelectValue /></SelectTrigger>
+              <SelectContent>
+                <SelectItem value="letter">Letter</SelectItem>
+                <SelectItem value="a4">A4</SelectItem>
+                <SelectItem value="legal">Legal</SelectItem>
+              </SelectContent>
+            </Select>
+          </div>
+          <div>
+            <Label htmlFor="pdf-margins">Margins</Label>
+            <Select value={margins} onValueChange={(v) => setMargins(v as typeof margins)}>
+              <SelectTrigger id="pdf-margins" aria-label="Margins"><SelectValue /></SelectTrigger>
+              <SelectContent>
+                <SelectItem value="narrow">Narrow</SelectItem>
+                <SelectItem value="normal">Normal</SelectItem>
+                <SelectItem value="wide">Wide</SelectItem>
+              </SelectContent>
+            </Select>
+          </div>
+          <label className="flex items-center gap-2">
+            <Checkbox checked={embed} onCheckedChange={(c) => setEmbed(!!c)} aria-label="Embed fonts" />
+            Embed fonts
+          </label>
+          <label className="flex items-center gap-2">
+            <Checkbox checked={ascii} onCheckedChange={(c) => setAscii(!!c)} aria-label="ASCII tables" />
+            Render tables as ASCII
+          </label>
+          {error && (
+            <div role="alert" className="rounded border border-destructive/40 bg-destructive/5 p-2 text-xs text-destructive">
+              {error}
+            </div>
+          )}
+        </div>
+        <ExportDialogFooter onCancel={closeModal} onSubmit={handleSubmit} submitting={submitting} submitLabel="Export" />
+      </DialogContent>
+    </Dialog>
+  );
+}

src/renderer/components/modals/ExportSettings.tsx

@@ -0,0 +1,66 @@
+import { useSettingsStore } from '@/stores/settings-store';
+import { Label } from '@/components/ui/label';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+import { Switch } from '@/components/ui/switch';
+
+export function ExportSettings() {
+  const { pdfFormat, pdfMargins, pdfEmbedFonts, docxTemplate, htmlHighlightStyle, renderTablesAsAscii, setSetting } = useSettingsStore();
+
+  return (
+    <div className="space-y-5 text-sm">
+      <div>
+        <Label htmlFor="export-pdf-format">Default PDF format</Label>
+        <Select value={pdfFormat} onValueChange={(v) => setSetting('pdfFormat', v as any)}>
+          <SelectTrigger id="export-pdf-format" aria-label="Default PDF format"><SelectValue /></SelectTrigger>
+          <SelectContent>
+            <SelectItem value="letter">Letter</SelectItem>
+            <SelectItem value="a4">A4</SelectItem>
+            <SelectItem value="legal">Legal</SelectItem>
+          </SelectContent>
+        </Select>
+      </div>
+      <div>
+        <Label htmlFor="export-pdf-margins">Default PDF margins</Label>
+        <Select value={pdfMargins} onValueChange={(v) => setSetting('pdfMargins', v as any)}>
+          <SelectTrigger id="export-pdf-margins" aria-label="Default PDF margins"><SelectValue /></SelectTrigger>
+          <SelectContent>
+            <SelectItem value="narrow">Narrow</SelectItem>
+            <SelectItem value="normal">Normal</SelectItem>
+            <SelectItem value="wide">Wide</SelectItem>
+          </SelectContent>
+        </Select>
+      </div>
+      <label className="flex items-center justify-between">
+        <span>Embed fonts in PDFs</span>
+        <Switch checked={pdfEmbedFonts} onCheckedChange={(c) => setSetting('pdfEmbedFonts', c)} aria-label="Embed fonts" />
+      </label>
+      <div>
+        <Label htmlFor="export-docx-template">Default DOCX template</Label>
+        <Select value={docxTemplate} onValueChange={(v) => setSetting('docxTemplate', v as any)}>
+          <SelectTrigger id="export-docx-template" aria-label="Default DOCX template"><SelectValue /></SelectTrigger>
+          <SelectContent>
+            <SelectItem value="standard">Standard</SelectItem>
+            <SelectItem value="minimal">Minimal</SelectItem>
+            <SelectItem value="modern">Modern</SelectItem>
+          </SelectContent>
+        </Select>
+      </div>
+      <div>
+        <Label htmlFor="export-html-highlight">Default HTML highlight</Label>
+        <Select value={htmlHighlightStyle} onValueChange={(v) => setSetting('htmlHighlightStyle', v as any)}>
+          <SelectTrigger id="export-html-highlight" aria-label="Default HTML highlight"><SelectValue /></SelectTrigger>
+          <SelectContent>
+            <SelectItem value="github">GitHub</SelectItem>
+            <SelectItem value="monokai">Monokai</SelectItem>
+            <SelectItem value="nord">Nord</SelectItem>
+            <SelectItem value="none">None</SelectItem>
+          </SelectContent>
+        </Select>
+      </div>
+      <label className="flex items-center justify-between">
+        <span>Render tables as ASCII by default</span>
+        <Switch checked={renderTablesAsAscii} onCheckedChange={(c) => setSetting('renderTablesAsAscii', c)} aria-label="ASCII tables by default" />
+      </label>
+    </div>
+  );
+}

src/renderer/components/modals/ModalLayer.tsx

@@ -0,0 +1,33 @@
+import { useAppStore } from '@/stores/app-store';
+import { AboutDialog } from './AboutDialog';
+import { ConfirmDialog } from './ConfirmDialog';
+import { ExportBatchDialog } from './ExportBatchDialog';
+import { ExportDocxDialog } from './ExportDocxDialog';
+import { ExportHtmlDialog } from './ExportHtmlDialog';
+import { ExportPdfDialog } from './ExportPdfDialog';
+import { SettingsSheet } from './SettingsSheet';
+import { WelcomeDialog } from './WelcomeDialog';
+
+export function ModalLayer() {
+  const modal = useAppStore((s) => s.modal);
+  switch (modal.kind) {
+    case null:
+      return null;
+    case 'export-pdf':
+      return <ExportPdfDialog sourcePath={modal.props.sourcePath} />;
+    case 'export-docx':
+      return <ExportDocxDialog sourcePath={modal.props.sourcePath} />;
+    case 'export-html':
+      return <ExportHtmlDialog sourcePath={modal.props.sourcePath} />;
+    case 'export-batch':
+      return <ExportBatchDialog sourcePaths={modal.props.sourcePaths} />;
+    case 'settings':
+      return <SettingsSheet />;
+    case 'about':
+      return <AboutDialog />;
+    case 'welcome':
+      return <WelcomeDialog />;
+    case 'confirm':
+      return <ConfirmDialog {...modal.props} />;
+  }
+}

src/renderer/components/modals/PluginsSettings.tsx

@@ -0,0 +1,14 @@
+import { Sparkles } from 'lucide-react';
+
+export function PluginsSettings() {
+  return (
+    <div className="flex flex-col items-center justify-center gap-3 py-12 text-center text-muted-foreground">
+      <Sparkles className="h-8 w-8 opacity-50" />
+      <h3 className="text-base font-semibold text-foreground">Coming soon</h3>
+      <p className="max-w-sm text-sm">
+        The plugin system is on the roadmap. You'll be able to extend MarkdownConverter with custom
+        commands, themes, and export formats.
+      </p>
+    </div>
+  );
+}

src/renderer/components/modals/SettingsSheet.tsx

@@ -0,0 +1,45 @@
+import { Sheet, SheetContent, SheetDescription, SheetHeader, SheetTitle } from '@/components/ui/sheet';
+import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
+import { Button } from '@/components/ui/button';
+import { useAppStore } from '@/stores/app-store';
+import { useSettingsStore } from '@/stores/settings-store';
+import { EditorSettings } from './EditorSettings';
+import { ThemeSettings } from './ThemeSettings';
+import { ExportSettings } from './ExportSettings';
+import { PluginsSettings } from './PluginsSettings';
+import { AboutSettings } from './AboutSettings';
+
+export function SettingsSheet() {
+  const closeModal = useAppStore((s) => s.closeModal);
+  const resetToDefaults = useSettingsStore((s) => s.resetToDefaults);
+
+  return (
+    <Sheet open onOpenChange={(o) => !o && closeModal()}>
+      <SheetContent aria-describedby="settings-desc" side="right" className="w-full sm:max-w-[480px]">
+        <SheetHeader>
+          <SheetTitle>Settings</SheetTitle>
+          <SheetDescription id="settings-desc">Editor, theme, and export preferences</SheetDescription>
+        </SheetHeader>
+        <Tabs defaultValue="editor" className="mt-4">
+          <TabsList className="grid w-full grid-cols-5">
+            <TabsTrigger value="editor">Editor</TabsTrigger>
+            <TabsTrigger value="theme">Theme</TabsTrigger>
+            <TabsTrigger value="export">Export</TabsTrigger>
+            <TabsTrigger value="plugins">Plugins</TabsTrigger>
+            <TabsTrigger value="about">About</TabsTrigger>
+          </TabsList>
+          <div className="mt-4 max-h-[70vh] overflow-y-auto pr-2">
+            <TabsContent value="editor"><EditorSettings /></TabsContent>
+            <TabsContent value="theme"><ThemeSettings /></TabsContent>
+            <TabsContent value="export"><ExportSettings /></TabsContent>
+            <TabsContent value="plugins"><PluginsSettings /></TabsContent>
+            <TabsContent value="about"><AboutSettings /></TabsContent>
+          </div>
+        </Tabs>
+        <div className="mt-4 flex justify-end border-t border-border pt-4">
+          <Button variant="ghost" onClick={resetToDefaults}>Reset to defaults</Button>
+        </div>
+      </SheetContent>
+    </Sheet>
+  );
+}

src/renderer/components/modals/ThemeSettings.tsx

@@ -0,0 +1,45 @@
+import { useSettingsStore } from '@/stores/settings-store';
+import { Label } from '@/components/ui/label';
+import { RadioGroup, RadioGroupItem } from '@/components/ui/radio-group';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+
+export function ThemeSettings() {
+  const { theme, accentColor, fontFamily, setSetting } = useSettingsStore();
+
+  return (
+    <div className="space-y-5 text-sm">
+      <div>
+        <Label>Mode</Label>
+        <RadioGroup value={theme} onValueChange={(v) => setSetting('theme', v as 'light' | 'dark' | 'auto')}>
+          <div className="flex items-center gap-2"><RadioGroupItem value="light" id="theme-light" /><Label htmlFor="theme-light">Light</Label></div>
+          <div className="flex items-center gap-2"><RadioGroupItem value="dark" id="theme-dark" /><Label htmlFor="theme-dark">Dark</Label></div>
+          <div className="flex items-center gap-2"><RadioGroupItem value="auto" id="theme-auto" /><Label htmlFor="theme-auto">Auto (system)</Label></div>
+        </RadioGroup>
+      </div>
+      <div>
+        <Label htmlFor="theme-accent">Accent color</Label>
+        <Select value={accentColor} onValueChange={(v) => setSetting('accentColor', v as any)}>
+          <SelectTrigger id="theme-accent" aria-label="Accent color"><SelectValue /></SelectTrigger>
+          <SelectContent>
+            <SelectItem value="brand">Brand (orange)</SelectItem>
+            <SelectItem value="blue">Blue</SelectItem>
+            <SelectItem value="green">Green</SelectItem>
+            <SelectItem value="purple">Purple</SelectItem>
+            <SelectItem value="orange">Orange</SelectItem>
+          </SelectContent>
+        </Select>
+      </div>
+      <div>
+        <Label htmlFor="theme-font-family">Editor font</Label>
+        <Select value={fontFamily} onValueChange={(v) => setSetting('fontFamily', v as any)}>
+          <SelectTrigger id="theme-font-family" aria-label="Editor font"><SelectValue /></SelectTrigger>
+          <SelectContent>
+            <SelectItem value="system">System (Plus Jakarta Sans)</SelectItem>
+            <SelectItem value="jetbrains">JetBrains Mono</SelectItem>
+            <SelectItem value="fira">Fira Code</SelectItem>
+          </SelectContent>
+        </Select>
+      </div>
+    </div>
+  );
+}

src/renderer/components/modals/WelcomeDialog.tsx

@@ -0,0 +1,51 @@
+import { useState } from 'react';
+import { Dialog, DialogContent, DialogDescription, DialogFooter, DialogHeader, DialogTitle } from '@/components/ui/dialog';
+import { Button } from '@/components/ui/button';
+import { Checkbox } from '@/components/ui/checkbox';
+import { useAppStore } from '@/stores/app-store';
+import { useSettingsStore } from '@/stores/settings-store';
+
+export function WelcomeDialog() {
+  const closeModal = useAppStore((s) => s.closeModal);
+  const setSetting = useSettingsStore((s) => s.setSetting);
+  const [dontShow, setDontShow] = useState(false);
+
+  const handleClose = () => {
+    if (dontShow) setSetting('welcomeDismissed', true);
+    closeModal();
+  };
+
+  return (
+    <Dialog open onOpenChange={(o) => !o && handleClose()}>
+      <DialogContent aria-describedby="welcome-desc" className="max-w-xl">
+        <DialogHeader>
+          <DialogTitle>Welcome to MarkdownConverter</DialogTitle>
+          <DialogDescription id="welcome-desc">
+            A polished editor for Markdown, with PDF, DOCX, and HTML export.
+          </DialogDescription>
+        </DialogHeader>
+        <div className="space-y-3 text-sm">
+          <div className="rounded-md border border-border bg-card/30 p-3">
+            <h3 className="font-semibold">1. Open a folder</h3>
+            <p className="text-muted-foreground">File → Open Folder, or ⌘O. Your tree appears on the left.</p>
+          </div>
+          <div className="rounded-md border border-border bg-card/30 p-3">
+            <h3 className="font-semibold">2. Edit & preview</h3>
+            <p className="text-muted-foreground">Type on the left, see the rendered preview on the right. Toggle with ⌘\.</p>
+          </div>
+          <div className="rounded-md border border-border bg-card/30 p-3">
+            <h3 className="font-semibold">3. Export anywhere</h3>
+            <p className="text-muted-foreground">File → Export to PDF / DOCX / HTML, or batch convert a folder.</p>
+          </div>
+        </div>
+        <DialogFooter className="flex-row items-center justify-between sm:justify-between">
+          <label className="flex items-center gap-2 text-xs text-muted-foreground">
+            <Checkbox checked={dontShow} onCheckedChange={(c) => setDontShow(!!c)} aria-label="Don't show again" />
+            Don't show again
+          </label>
+          <Button onClick={handleClose}>Get started</Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  );
+}

src/renderer/components/preview/MarkdownRenderer.tsx

@@ -0,0 +1,44 @@
+import { useEffect, useRef, useState } from 'react';
+import { renderMarkdown } from '@/lib/markdown';
+import { MermaidLazy } from './MermaidLazy';
+
+interface Props {
+  source: string;
+}
+
+const MERMAID_RE = /```mermaid\n([\s\S]*?)```/g;
+
+function extractMermaidCodes(source: string): string[] {
+  const codes: string[] = [];
+  let match: RegExpExecArray | null;
+  while ((match = MERMAID_RE.exec(source)) !== null) {
+    codes.push(match[1].trim());
+  }
+  return codes;
+}
+
+export function MarkdownRenderer({ source }: Props) {
+  const html = renderMarkdown(source);
+  const containerRef = useRef<HTMLDivElement>(null);
+  const [mermaidCodes, setMermaidCodes] = useState<string[]>([]);
+
+  // Re-derive mermaid codes from the original source. The renderMarkdown function
+  // replaces mermaid blocks with placeholders (data-mermaid-source="${idx}"), but
+  // it does not return the actual codes. Rather than thread them through the API,
+  // we re-extract from the source. Source is small (single buffer content) so this
+  // cost is negligible.
+  useEffect(() => {
+    setMermaidCodes(extractMermaidCodes(source));
+  }, [source]);
+
+  return (
+    <div className="prose prose-neutral dark:prose-invert max-w-none p-6" ref={containerRef}>
+      <div dangerouslySetInnerHTML={{ __html: html }} />
+      {mermaidCodes.map((code, i) => (
+        <div key={i} className="my-4">
+          <MermaidLazy code={code} />
+        </div>
+      ))}
+    </div>
+  );
+}

src/renderer/components/preview/MermaidLazy.tsx

@@ -0,0 +1,45 @@
+import { useEffect, useRef, useState } from 'react';
+
+interface Props {
+  code: string;
+}
+
+let mermaidModule: typeof import('mermaid').default | null = null;
+let initialized = false;
+
+async function getMermaid() {
+  if (!mermaidModule) {
+    const mod = await import('mermaid');
+    mermaidModule = mod.default;
+  }
+  if (!initialized) {
+    mermaidModule.initialize({ startOnLoad: false, theme: 'default' });
+    initialized = true;
+  }
+  return mermaidModule;
+}
+
+export function MermaidLazy({ code }: Props) {
+  const [svg, setSvg] = useState<string | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const idRef = useRef(`mermaid-${Math.random().toString(36).slice(2)}`);
+
+  useEffect(() => {
+    let cancelled = false;
+    getMermaid()
+      .then((m) => m.render(idRef.current, code))
+      .then((rendered) => {
+        if (!cancelled) setSvg(rendered);
+      })
+      .catch((err: Error) => {
+        if (!cancelled) setError(err.message);
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, [code]);
+
+  if (error) return <div className="rounded border border-destructive/40 bg-destructive/5 p-2 text-xs text-destructive">{error}</div>;
+  if (!svg) return <div className="text-xs text-muted-foreground">Loading diagram…</div>;
+  return <div data-testid="mermaid-output" dangerouslySetInnerHTML={{ __html: svg }} />;
+}

src/renderer/components/preview/PreviewPane.tsx

@@ -0,0 +1,22 @@
+import { MarkdownRenderer } from './MarkdownRenderer';
+import { usePreviewStore } from '@/stores/preview-store';
+import { useScrollSync } from '@/hooks/use-scroll-sync';
+
+export function PreviewPane() {
+  const { source, setScrollRatio } = usePreviewStore();
+  const { handlePreviewScroll } = useScrollSync({ onPreviewScroll: setScrollRatio });
+
+  if (!source) {
+    return (
+      <div className="flex h-full items-center justify-center text-muted-foreground">
+        <p>Nothing to preview. Start typing in the editor.</p>
+      </div>
+    );
+  }
+
+  return (
+    <div className="h-full overflow-auto bg-card/10" onScroll={handlePreviewScroll}>
+      <MarkdownRenderer source={source} />
+    </div>
+  );
+}

src/renderer/components/sidebar/FileTree.tsx

@@ -0,0 +1,73 @@
+import { ChevronRight, Folder, FolderOpen, File, FileText } from 'lucide-react';
+import { useFileStore } from '@/stores/file-store';
+import { cn } from '@/lib/utils';
+
+function FileTreeNode({ node, depth }: { node: import('@/stores/file-store').FileNode; depth: number }) {
+  const { expanded, activeTabId, loadChildren, toggleExpanded, openFile } = useFileStore();
+  const isExpanded = expanded.has(node.path);
+  const isActive = activeTabId === node.path;
+
+  if (node.isDirectory) {
+    const handleClick = async () => {
+      if (!node.loaded) {
+        await loadChildren(node.path);
+      }
+      toggleExpanded(node.path);
+    };
+
+    return (
+      <div>
+        <button
+          onClick={handleClick}
+          className={cn(
+            'flex w-full items-center gap-1 rounded px-1 py-0.5 text-left text-xs hover:bg-accent',
+            isActive && 'bg-accent'
+          )}
+          style={{ paddingLeft: `${depth * 16 + 4}px` }}
+        >
+          <ChevronRight
+            size={12}
+            className={cn('transition-transform duration-150', isExpanded && 'rotate-90')}
+          />
+          {isExpanded ? <FolderOpen size={14} /> : <Folder size={14} />}
+          <span className="truncate">{node.name}</span>
+        </button>
+        {isExpanded && node.loaded && node.children && (
+          <div>
+            {node.children.map((child) => (
+              <FileTreeNode key={child.path} node={child} depth={depth + 1} />
+            ))}
+          </div>
+        )}
+      </div>
+    );
+  }
+
+  return (
+    <button
+      onClick={() => openFile(node.path)}
+      className={cn(
+        'flex w-full items-center gap-1 rounded px-1 py-0.5 text-left text-xs hover:bg-accent',
+        isActive && 'bg-accent text-accent-foreground'
+      )}
+      style={{ paddingLeft: `${depth * 16 + 4}px` }}
+    >
+      <FileText size={14} />
+      <span className="truncate">{node.name}</span>
+    </button>
+  );
+}
+
+export function FileTree() {
+  const tree = useFileStore((s) => s.tree);
+
+  if (!tree) return null;
+
+  return (
+    <div className="py-1">
+      {tree.children?.map((child) => (
+        <FileTreeNode key={child.path} node={child} depth={0} />
+      ))}
+    </div>
+  );
+}

src/renderer/components/sidebar/Outline.tsx

@@ -0,0 +1,77 @@
+import { useEditorStore } from '@/stores/editor-store';
+
+const HEADING_RE = /^(#{1,6})\s+(.+)$/gm;
+
+interface HeadingItem {
+  level: number;
+  text: string;
+  line: number;
+}
+
+function extractHeadings(content: string): HeadingItem[] {
+  const headings: HeadingItem[] = [];
+  let match: RegExpExecArray | null;
+  const re = new RegExp(HEADING_RE.source, 'gm');
+  let lineNum = 1;
+  for (const line of content.split('\n')) {
+    re.lastIndex = 0;
+    match = re.exec(line);
+    if (match) {
+      headings.push({
+        level: match[1].length,
+        text: match[2].trim(),
+        line: lineNum,
+      });
+    }
+    lineNum++;
+  }
+  return headings;
+}
+
+export function Outline() {
+  const activeId = useEditorStore((s) => s.activeId);
+  const buffers = useEditorStore((s) => s.buffers);
+
+  if (!activeId) {
+    return (
+      <div className="flex flex-col items-center justify-center gap-2 py-8 text-xs text-muted-foreground">
+        <span>No file open</span>
+      </div>
+    );
+  }
+
+  const buffer = buffers.get(activeId);
+  if (!buffer) {
+    return (
+      <div className="flex flex-col items-center justify-center gap-2 py-8 text-xs text-muted-foreground">
+        <span>No file open</span>
+      </div>
+    );
+  }
+
+  const headings = extractHeadings(buffer.content);
+
+  if (headings.length === 0) {
+    return (
+      <div className="flex flex-col items-center justify-center gap-2 py-8 text-xs text-muted-foreground">
+        <span>No headings</span>
+      </div>
+    );
+  }
+
+  return (
+    <div className="flex flex-col gap-0.5 py-1">
+      {headings.map((h, i) => (
+        <button
+          key={i}
+          onClick={() => {}}
+          className="flex items-center gap-1 rounded px-2 py-0.5 text-left text-xs hover:bg-accent"
+          style={{ paddingLeft: `${(h.level - 1) * 16 + 8}px` }}
+        >
+          <span className="truncate text-muted-foreground">#{h.level}</span>
+          <span className="truncate">{h.text}</span>
+        </button>
+      ))}
+    </div>
+  );
+}

src/renderer/components/sidebar/Sidebar.tsx

@@ -0,0 +1,54 @@
+import { ChevronRight, FolderOpen } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+import { Collapsible, CollapsibleTrigger, CollapsibleContent } from '@/components/ui/collapsible';
+import { ScrollArea } from '@/components/ui/scroll-area';
+import { useFileStore } from '@/stores/file-store';
+import { FileTree } from './FileTree';
+import { Outline } from './Outline';
+
+export function Sidebar() {
+  const tree = useFileStore((s) => s.tree);
+
+  return (
+    <div className="flex h-full flex-col gap-3">
+      {/* Files section */}
+      <Collapsible defaultOpen>
+        <CollapsibleTrigger asChild>
+          <button className="flex w-full items-center gap-1.5 px-1 py-1.5 text-xs font-medium hover:bg-accent rounded">
+            <ChevronRight size={12} className="rotate-90" />
+            Files
+          </button>
+        </CollapsibleTrigger>
+        <CollapsibleContent>
+          <ScrollArea className="h-[calc(100vh-240px)]">
+            {!tree ? (
+              <div className="flex flex-col items-center gap-2 p-4 text-xs text-muted-foreground">
+                <span>No folder opened</span>
+                <Button size="sm" variant="outline" onClick={() => useFileStore.getState().openFolderDialog()}>
+                  <FolderOpen className="mr-1" /> Open Folder
+                </Button>
+              </div>
+            ) : (
+              <FileTree />
+            )}
+          </ScrollArea>
+        </CollapsibleContent>
+      </Collapsible>
+
+      {/* Outline section */}
+      <Collapsible defaultOpen>
+        <CollapsibleTrigger asChild>
+          <button className="flex w-full items-center gap-1.5 px-1 py-1.5 text-xs font-medium hover:bg-accent rounded">
+            <ChevronRight size={12} className="rotate-90" />
+            Outline
+          </button>
+        </CollapsibleTrigger>
+        <CollapsibleContent>
+          <ScrollArea className="h-[calc(100vh-240px)]">
+            <Outline />
+          </ScrollArea>
+        </CollapsibleContent>
+      </Collapsible>
+    </div>
+  );
+}

src/renderer/components/theme-provider.tsx

@@ -0,0 +1,6 @@
+import { ThemeProvider as NextThemesProvider } from 'next-themes';
+import type { ComponentProps } from 'react';
+
+export function ThemeProvider({ children, ...props }: ComponentProps<typeof NextThemesProvider>) {
+  return <NextThemesProvider {...props}>{children}</NextThemesProvider>;
+}

src/renderer/components/theme-toggle.tsx

@@ -0,0 +1,30 @@
+import { useTheme } from 'next-themes';
+import { Moon, Sun } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+import { useEffect, useState } from 'react';
+
+export function ThemeToggle() {
+  const { resolvedTheme, setTheme } = useTheme();
+  const [mounted, setMounted] = useState(false);
+  useEffect(() => setMounted(true), []);
+
+  if (!mounted) {
+    return (
+      <Button variant="ghost" size="icon" aria-label="Toggle theme" className="opacity-0">
+        <Sun className="h-4 w-4" />
+      </Button>
+    );
+  }
+
+  const isDark = resolvedTheme === 'dark';
+  return (
+    <Button
+      variant="ghost"
+      size="icon"
+      aria-label="Toggle theme"
+      onClick={() => setTheme(isDark ? 'light' : 'dark')}
+    >
+      {isDark ? <Sun className="h-4 w-4" /> : <Moon className="h-4 w-4" />}
+    </Button>
+  );
+}

src/renderer/components/ui/button.tsx

@@ -0,0 +1,57 @@
+import * as React from "react"
+import { Slot } from "@radix-ui/react-slot"
+import { cva, type VariantProps } from "class-variance-authority"
+
+import { cn } from "@/lib/utils"
+
+const buttonVariants = cva(
+  "inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-md text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:pointer-events-none disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0",
+  {
+    variants: {
+      variant: {
+        default:
+          "bg-primary text-primary-foreground shadow hover:bg-primary/90",
+        destructive:
+          "bg-destructive text-destructive-foreground shadow-sm hover:bg-destructive/90",
+        outline:
+          "border border-input bg-background shadow-sm hover:bg-accent hover:text-accent-foreground",
+        secondary:
+          "bg-secondary text-secondary-foreground shadow-sm hover:bg-secondary/80",
+        ghost: "hover:bg-accent hover:text-accent-foreground",
+        link: "text-primary underline-offset-4 hover:underline",
+      },
+      size: {
+        default: "h-9 px-4 py-2",
+        sm: "h-8 rounded-md px-3 text-xs",
+        lg: "h-10 rounded-md px-8",
+        icon: "h-9 w-9",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+      size: "default",
+    },
+  }
+)
+
+export interface ButtonProps
+  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
+    VariantProps<typeof buttonVariants> {
+  asChild?: boolean
+}
+
+const Button = React.forwardRef<HTMLButtonElement, ButtonProps>(
+  ({ className, variant, size, asChild = false, ...props }, ref) => {
+    const Comp = asChild ? Slot : "button"
+    return (
+      <Comp
+        className={cn(buttonVariants({ variant, size, className }))}
+        ref={ref}
+        {...props}
+      />
+    )
+  }
+)
+Button.displayName = "Button"
+
+export { Button, buttonVariants }

src/renderer/components/ui/checkbox.tsx

@@ -0,0 +1,27 @@
+import * as React from "react"
+import * as CheckboxPrimitive from "@radix-ui/react-checkbox"
+import { Check } from "lucide-react"
+import { cn } from "@/lib/utils"
+
+const Checkbox = React.forwardRef<
+  React.ElementRef<typeof CheckboxPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof CheckboxPrimitive.Root>
+>(({ className, ...props }, ref) => (
+  <CheckboxPrimitive.Root
+    ref={ref}
+    className={cn(
+      "peer h-4 w-4 shrink-0 rounded-sm border border-primary ring-offset-background focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50 data-[state=checked]:bg-primary data-[state=checked]:text-primary-foreground",
+      className
+    )}
+    {...props}
+  >
+    <CheckboxPrimitive.Indicator
+      className={cn("flex items-center justify-center text-current")}
+    >
+      <Check className="h-4 w-4" />
+    </CheckboxPrimitive.Indicator>
+  </CheckboxPrimitive.Root>
+))
+Checkbox.displayName = CheckboxPrimitive.Root.displayName
+
+export { Checkbox }

src/renderer/components/ui/collapsible.tsx

@@ -0,0 +1,11 @@
+"use client"
+
+import * as CollapsiblePrimitive from "@radix-ui/react-collapsible"
+
+const Collapsible = CollapsiblePrimitive.Root
+
+const CollapsibleTrigger = CollapsiblePrimitive.CollapsibleTrigger
+
+const CollapsibleContent = CollapsiblePrimitive.CollapsibleContent
+
+export { Collapsible, CollapsibleTrigger, CollapsibleContent }

src/renderer/components/ui/context-menu.tsx

@@ -0,0 +1,200 @@
+"use client"
+
+import * as React from "react"
+import * as ContextMenuPrimitive from "@radix-ui/react-context-menu"
+import { Check, ChevronRight, Circle } from "lucide-react"
+
+import { cn } from "@/lib/utils"
+
+const ContextMenu = ContextMenuPrimitive.Root
+
+const ContextMenuTrigger = ContextMenuPrimitive.Trigger
+
+const ContextMenuGroup = ContextMenuPrimitive.Group
+
+const ContextMenuPortal = ContextMenuPrimitive.Portal
+
+const ContextMenuSub = ContextMenuPrimitive.Sub
+
+const ContextMenuRadioGroup = ContextMenuPrimitive.RadioGroup
+
+const ContextMenuSubTrigger = React.forwardRef<
+  React.ElementRef<typeof ContextMenuPrimitive.SubTrigger>,
+  React.ComponentPropsWithoutRef<typeof ContextMenuPrimitive.SubTrigger> & {
+    inset?: boolean
+  }
+>(({ className, inset, children, ...props }, ref) => (
+  <ContextMenuPrimitive.SubTrigger
+    ref={ref}
+    className={cn(
+      "flex cursor-default select-none items-center rounded-sm px-2 py-1.5 text-sm outline-none focus:bg-accent focus:text-accent-foreground data-[state=open]:bg-accent data-[state=open]:text-accent-foreground",
+      inset && "pl-8",
+      className
+    )}
+    {...props}
+  >
+    {children}
+    <ChevronRight className="ml-auto h-4 w-4" />
+  </ContextMenuPrimitive.SubTrigger>
+))
+ContextMenuSubTrigger.displayName = ContextMenuPrimitive.SubTrigger.displayName
+
+const ContextMenuSubContent = React.forwardRef<
+  React.ElementRef<typeof ContextMenuPrimitive.SubContent>,
+  React.ComponentPropsWithoutRef<typeof ContextMenuPrimitive.SubContent>
+>(({ className, ...props }, ref) => (
+  <ContextMenuPrimitive.SubContent
+    ref={ref}
+    className={cn(
+      "z-50 min-w-[8rem] overflow-hidden rounded-md border bg-popover p-1 text-popover-foreground shadow-lg data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 origin-[--radix-context-menu-content-transform-origin]",
+      className
+    )}
+    {...props}
+  />
+))
+ContextMenuSubContent.displayName = ContextMenuPrimitive.SubContent.displayName
+
+const ContextMenuContent = React.forwardRef<
+  React.ElementRef<typeof ContextMenuPrimitive.Content>,
+  React.ComponentPropsWithoutRef<typeof ContextMenuPrimitive.Content>
+>(({ className, ...props }, ref) => (
+  <ContextMenuPrimitive.Portal>
+    <ContextMenuPrimitive.Content
+      ref={ref}
+      className={cn(
+        "z-50 max-h-[--radix-context-menu-content-available-height] min-w-[8rem] overflow-y-auto overflow-x-hidden rounded-md border bg-popover p-1 text-popover-foreground shadow-md data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 origin-[--radix-context-menu-content-transform-origin]",
+        className
+      )}
+      {...props}
+    />
+  </ContextMenuPrimitive.Portal>
+))
+ContextMenuContent.displayName = ContextMenuPrimitive.Content.displayName
+
+const ContextMenuItem = React.forwardRef<
+  React.ElementRef<typeof ContextMenuPrimitive.Item>,
+  React.ComponentPropsWithoutRef<typeof ContextMenuPrimitive.Item> & {
+    inset?: boolean
+  }
+>(({ className, inset, ...props }, ref) => (
+  <ContextMenuPrimitive.Item
+    ref={ref}
+    className={cn(
+      "relative flex cursor-default select-none items-center rounded-sm px-2 py-1.5 text-sm outline-none focus:bg-accent focus:text-accent-foreground data-[disabled]:pointer-events-none data-[disabled]:opacity-50",
+      inset && "pl-8",
+      className
+    )}
+    {...props}
+  />
+))
+ContextMenuItem.displayName = ContextMenuPrimitive.Item.displayName
+
+const ContextMenuCheckboxItem = React.forwardRef<
+  React.ElementRef<typeof ContextMenuPrimitive.CheckboxItem>,
+  React.ComponentPropsWithoutRef<typeof ContextMenuPrimitive.CheckboxItem>
+>(({ className, children, checked, ...props }, ref) => (
+  <ContextMenuPrimitive.CheckboxItem
+    ref={ref}
+    className={cn(
+      "relative flex cursor-default select-none items-center rounded-sm py-1.5 pl-8 pr-2 text-sm outline-none focus:bg-accent focus:text-accent-foreground data-[disabled]:pointer-events-none data-[disabled]:opacity-50",
+      className
+    )}
+    checked={checked}
+    {...props}
+  >
+    <span className="absolute left-2 flex h-3.5 w-3.5 items-center justify-center">
+      <ContextMenuPrimitive.ItemIndicator>
+        <Check className="h-4 w-4" />
+      </ContextMenuPrimitive.ItemIndicator>
+    </span>
+    {children}
+  </ContextMenuPrimitive.CheckboxItem>
+))
+ContextMenuCheckboxItem.displayName =
+  ContextMenuPrimitive.CheckboxItem.displayName
+
+const ContextMenuRadioItem = React.forwardRef<
+  React.ElementRef<typeof ContextMenuPrimitive.RadioItem>,
+  React.ComponentPropsWithoutRef<typeof ContextMenuPrimitive.RadioItem>
+>(({ className, children, ...props }, ref) => (
+  <ContextMenuPrimitive.RadioItem
+    ref={ref}
+    className={cn(
+      "relative flex cursor-default select-none items-center rounded-sm py-1.5 pl-8 pr-2 text-sm outline-none focus:bg-accent focus:text-accent-foreground data-[disabled]:pointer-events-none data-[disabled]:opacity-50",
+      className
+    )}
+    {...props}
+  >
+    <span className="absolute left-2 flex h-3.5 w-3.5 items-center justify-center">
+      <ContextMenuPrimitive.ItemIndicator>
+        <Circle className="h-4 w-4 fill-current" />
+      </ContextMenuPrimitive.ItemIndicator>
+    </span>
+    {children}
+  </ContextMenuPrimitive.RadioItem>
+))
+ContextMenuRadioItem.displayName = ContextMenuPrimitive.RadioItem.displayName
+
+const ContextMenuLabel = React.forwardRef<
+  React.ElementRef<typeof ContextMenuPrimitive.Label>,
+  React.ComponentPropsWithoutRef<typeof ContextMenuPrimitive.Label> & {
+    inset?: boolean
+  }
+>(({ className, inset, ...props }, ref) => (
+  <ContextMenuPrimitive.Label
+    ref={ref}
+    className={cn(
+      "px-2 py-1.5 text-sm font-semibold text-foreground",
+      inset && "pl-8",
+      className
+    )}
+    {...props}
+  />
+))
+ContextMenuLabel.displayName = ContextMenuPrimitive.Label.displayName
+
+const ContextMenuSeparator = React.forwardRef<
+  React.ElementRef<typeof ContextMenuPrimitive.Separator>,
+  React.ComponentPropsWithoutRef<typeof ContextMenuPrimitive.Separator>
+>(({ className, ...props }, ref) => (
+  <ContextMenuPrimitive.Separator
+    ref={ref}
+    className={cn("-mx-1 my-1 h-px bg-border", className)}
+    {...props}
+  />
+))
+ContextMenuSeparator.displayName = ContextMenuPrimitive.Separator.displayName
+
+const ContextMenuShortcut = ({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLSpanElement>) => {
+  return (
+    <span
+      className={cn(
+        "ml-auto text-xs tracking-widest text-muted-foreground",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+ContextMenuShortcut.displayName = "ContextMenuShortcut"
+
+export {
+  ContextMenu,
+  ContextMenuTrigger,
+  ContextMenuContent,
+  ContextMenuItem,
+  ContextMenuCheckboxItem,
+  ContextMenuRadioItem,
+  ContextMenuLabel,
+  ContextMenuSeparator,
+  ContextMenuShortcut,
+  ContextMenuGroup,
+  ContextMenuPortal,
+  ContextMenuSub,
+  ContextMenuSubContent,
+  ContextMenuSubTrigger,
+  ContextMenuRadioGroup,
+}

src/renderer/components/ui/dialog.tsx

@@ -0,0 +1,158 @@
+"use client"
+
+import * as React from "react"
+import { XIcon } from "lucide-react"
+import * as DialogPrimitive from "@radix-ui/react-dialog"
+
+import { cn } from "@/lib/utils"
+import { Button } from "@/components/ui/button"
+
+function Dialog({
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Root>) {
+  return <DialogPrimitive.Root data-slot="dialog" {...props} />
+}
+
+function DialogTrigger({
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Trigger>) {
+  return <DialogPrimitive.Trigger data-slot="dialog-trigger" {...props} />
+}
+
+function DialogPortal({
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Portal>) {
+  return <DialogPrimitive.Portal data-slot="dialog-portal" {...props} />
+}
+
+function DialogClose({
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Close>) {
+  return <DialogPrimitive.Close data-slot="dialog-close" {...props} />
+}
+
+function DialogOverlay({
+  className,
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Overlay>) {
+  return (
+    <DialogPrimitive.Overlay
+      data-slot="dialog-overlay"
+      className={cn(
+        "fixed inset-0 z-50 bg-black/50 data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:animate-in data-[state=open]:fade-in-0",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function DialogContent({
+  className,
+  children,
+  showCloseButton = true,
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Content> & {
+  showCloseButton?: boolean
+}) {
+  return (
+    <DialogPortal data-slot="dialog-portal">
+      <DialogOverlay />
+      <DialogPrimitive.Content
+        data-slot="dialog-content"
+        className={cn(
+          "fixed top-[50%] left-[50%] z-50 grid w-full max-w-[calc(100%-2rem)] translate-x-[-50%] translate-y-[-50%] gap-4 rounded-lg border bg-background p-6 shadow-lg duration-200 outline-none data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=closed]:zoom-out-95 data-[state=open]:animate-in data-[state=open]:fade-in-0 data-[state=open]:zoom-in-95 sm:max-w-lg",
+          className
+        )}
+        {...props}
+      >
+        {children}
+        {showCloseButton && (
+          <DialogPrimitive.Close
+            data-slot="dialog-close"
+            className="absolute top-4 right-4 rounded-xs opacity-70 ring-offset-background transition-opacity hover:opacity-100 focus:ring-2 focus:ring-ring focus:ring-offset-2 focus:outline-hidden disabled:pointer-events-none data-[state=open]:bg-accent data-[state=open]:text-muted-foreground [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4"
+          >
+            <XIcon />
+            <span className="sr-only">Close</span>
+          </DialogPrimitive.Close>
+        )}
+      </DialogPrimitive.Content>
+    </DialogPortal>
+  )
+}
+
+function DialogHeader({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="dialog-header"
+      className={cn("flex flex-col gap-2 text-center sm:text-left", className)}
+      {...props}
+    />
+  )
+}
+
+function DialogFooter({
+  className,
+  showCloseButton = false,
+  children,
+  ...props
+}: React.ComponentProps<"div"> & {
+  showCloseButton?: boolean
+}) {
+  return (
+    <div
+      data-slot="dialog-footer"
+      className={cn(
+        "flex flex-col-reverse gap-2 sm:flex-row sm:justify-end",
+        className
+      )}
+      {...props}
+    >
+      {children}
+      {showCloseButton && (
+        <DialogPrimitive.Close asChild>
+          <Button variant="outline">Close</Button>
+        </DialogPrimitive.Close>
+      )}
+    </div>
+  )
+}
+
+function DialogTitle({
+  className,
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Title>) {
+  return (
+    <DialogPrimitive.Title
+      data-slot="dialog-title"
+      className={cn("text-lg leading-none font-semibold", className)}
+      {...props}
+    />
+  )
+}
+
+function DialogDescription({
+  className,
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Description>) {
+  return (
+    <DialogPrimitive.Description
+      data-slot="dialog-description"
+      className={cn("text-sm text-muted-foreground", className)}
+      {...props}
+    />
+  )
+}
+
+export {
+  Dialog,
+  DialogClose,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogOverlay,
+  DialogPortal,
+  DialogTitle,
+  DialogTrigger,
+}

src/renderer/components/ui/form.tsx

@@ -0,0 +1,153 @@
+"use client"
+
+import * as React from "react"
+import * as LabelPrimitive from "@radix-ui/react-label"
+import { Slot } from "@radix-ui/react-slot"
+import {
+  Controller,
+  type ControllerProps,
+  type FieldPath,
+  type FieldValues,
+  useFormContext,
+} from "react-hook-form"
+
+import { cn } from "@/lib/utils"
+
+const Form = React.forwardRef<
+  HTMLFormElement,
+  React.ComponentProps<"form">
+>(({ className, ...props }, ref) => {
+  const methods = useFormContext()
+  return (
+    <form ref={ref} className={className} onSubmit={methods.handleSubmit(() => {})} {...props} />
+  )
+})
+Form.displayName = "Form"
+
+// ============================================================
+// FormFieldContext - provides field-level context
+// ============================================================
+
+const FormFieldContext = React.createContext<
+  ControllerProps<FieldValues, string>
+>({} as never)
+
+const FormField = <
+  TFieldValues extends FieldValues = FieldValues,
+  TName extends FieldPath<TFieldValues> = FieldPath<TFieldValues>
+>({
+  ...props
+}: ControllerProps<TFieldValues, TName>) => {
+  const { name } = props
+
+  return (
+    <FormFieldContext.Provider value={props as ControllerProps<FieldValues, string>}>
+      <Controller {...props} />
+    </FormFieldContext.Provider>
+  )
+}
+
+// ============================================================
+// useFormField - must be used inside a FormField
+// ============================================================
+
+function useFormField(): ControllerProps<FieldValues, string> {
+  const fieldContext = React.useContext(FormFieldContext)
+  if (!fieldContext) {
+    throw new Error("useFormField must be used within a FormField")
+  }
+  return fieldContext
+}
+
+// ============================================================
+// FormItem - wraps a labeled form control
+// ============================================================
+
+const FormItem = React.forwardRef<
+  HTMLDivElement,
+  React.HTMLAttributes<HTMLDivElement>
+>(({ className, ...props }, ref) => (
+  <div ref={ref} className={cn("space-y-2", className)} {...props} />
+))
+FormItem.displayName = "FormItem"
+
+// ============================================================
+// FormLabel
+// ============================================================
+
+const FormLabel = React.forwardRef<
+  React.ElementRef<typeof LabelPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof LabelPrimitive.Root>
+>(({ className, ...props }, ref) => (
+  <LabelPrimitive.Root
+    ref={ref}
+    className={cn(
+      "text-sm font-medium leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70",
+      className
+    )}
+    {...props}
+  />
+))
+FormLabel.displayName = LabelPrimitive.Root.displayName
+
+// ============================================================
+// FormControl - Slot bridge
+// ============================================================
+
+const FormControl = React.forwardRef<
+  React.ElementRef<typeof Slot>,
+  React.ComponentPropsWithoutRef<typeof Slot>
+>(({ ...props }, ref) => (
+  <Slot ref={ref} {...props} />
+))
+FormControl.displayName = "FormControl"
+
+// ============================================================
+// FormDescription
+// ============================================================
+
+const FormDescription = React.forwardRef<
+  HTMLParagraphElement,
+  React.HTMLAttributes<HTMLParagraphElement>
+>(({ className, ...props }, ref) => (
+  <p
+    ref={ref}
+    className={cn("text-sm text-muted-foreground", className)}
+    {...props}
+  />
+))
+FormDescription.displayName = "FormDescription"
+
+// ============================================================
+// FormMessage
+// ============================================================
+
+const FormMessage = React.forwardRef<
+  HTMLParagraphElement,
+  React.HTMLAttributes<HTMLParagraphElement>
+>(({ className, children, ...props }, ref) => {
+  const { error } = useFormField()
+  const body = error ? String(error.message ?? "") : children
+  if (!body) return null
+  return (
+    <p
+      ref={ref}
+      className={cn("text-sm font-medium text-destructive", className)}
+      {...props}
+    >
+      {body}
+    </p>
+  )
+})
+FormMessage.displayName = "FormMessage"
+
+export {
+  Form,
+  FormField,
+  FormItem,
+  FormLabel,
+  FormControl,
+  FormDescription,
+  FormMessage,
+  useFormField,
+}

src/renderer/components/ui/input.tsx

@@ -0,0 +1,25 @@
+import * as React from "react"
+
+import { cn } from "@/lib/utils"
+
+export interface InputProps
+  extends React.InputHTMLAttributes<HTMLInputElement> {}
+
+const Input = React.forwardRef<HTMLInputElement, InputProps>(
+  ({ className, type, ...props }, ref) => {
+    return (
+      <input
+        type={type}
+        className={cn(
+          "h-10 w-full rounded-md border border-input bg-background px-3 py-2 text-sm ring-offset-background file:border-0 file:bg-transparent file:text-sm file:font-medium placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50",
+          className
+        )}
+        ref={ref}
+        {...props}
+      />
+    )
+  }
+)
+Input.displayName = "Input"
+
+export { Input }

src/renderer/components/ui/label.tsx

@@ -0,0 +1,20 @@
+import * as React from "react"
+import * as LabelPrimitive from "@radix-ui/react-label"
+import { cn } from "@/lib/utils"
+
+const Label = React.forwardRef<
+  React.ElementRef<typeof LabelPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof LabelPrimitive.Root>
+>(({ className, ...props }, ref) => (
+  <LabelPrimitive.Root
+    ref={ref}
+    className={cn(
+      "text-sm font-medium leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70",
+      className
+    )}
+    {...props}
+  />
+))
+Label.displayName = LabelPrimitive.Root.displayName
+
+export { Label }

src/renderer/components/ui/radio-group.tsx

@@ -0,0 +1,41 @@
+import * as React from "react"
+import * as RadioGroupPrimitive from "@radix-ui/react-radio-group"
+import { Circle } from "lucide-react"
+import { cn } from "@/lib/utils"
+
+const RadioGroup = React.forwardRef<
+  React.ElementRef<typeof RadioGroupPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof RadioGroupPrimitive.Root>
+>(({ className, ...props }, ref) => {
+  return (
+    <RadioGroupPrimitive.Root
+      className={cn("grid gap-2", className)}
+      {...props}
+      ref={ref}
+    />
+  )
+})
+RadioGroup.displayName = RadioGroupPrimitive.Root.displayName
+
+const RadioGroupItem = React.forwardRef<
+  React.ElementRef<typeof RadioGroupPrimitive.Item>,
+  React.ComponentPropsWithoutRef<typeof RadioGroupPrimitive.Item>
+>(({ className, ...props }, ref) => {
+  return (
+    <RadioGroupPrimitive.Item
+      ref={ref}
+      className={cn(
+        "aspect-square h-4 w-4 rounded-full border border-primary text-primary ring-offset-background focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50",
+        className
+      )}
+      {...props}
+    >
+      <RadioGroupPrimitive.Indicator className="flex items-center justify-center">
+        <Circle className="h-2.5 w-2.5 fill-current text-current" />
+      </RadioGroupPrimitive.Indicator>
+    </RadioGroupPrimitive.Item>
+  )
+})
+RadioGroupItem.displayName = RadioGroupPrimitive.Item.displayName
+
+export { RadioGroup, RadioGroupItem }

src/renderer/components/ui/resizable.tsx

@@ -0,0 +1,62 @@
+"use client"
+
+import * as React from "react"
+import { GripVertical } from "lucide-react"
+import * as ResizablePrimitive from "react-resizable-panels"
+
+import { cn } from "@/lib/utils"
+
+const ResizablePanelGroup = React.forwardRef<
+  React.ElementRef<typeof ResizablePrimitive.Group>,
+  React.ComponentPropsWithoutRef<typeof ResizablePrimitive.Group>
+>(({ className, ...props }, ref) => (
+  <ResizablePrimitive.Group
+    ref={ref}
+    className={cn(
+      "flex h-full w-full data-[panel-group-direction=vertical]:flex-col",
+      className
+    )}
+    {...props}
+  />
+))
+ResizablePanelGroup.displayName = "ResizablePanelGroup"
+
+const ResizablePanel = React.forwardRef<
+  React.ElementRef<typeof ResizablePrimitive.Panel>,
+  React.ComponentPropsWithoutRef<typeof ResizablePrimitive.Panel>
+>(({ className, ...props }, ref) => (
+  <ResizablePrimitive.Panel
+    ref={ref}
+    className={cn(
+      "h-full w-full overflow-hidden",
+      className
+    )}
+    {...props}
+  />
+))
+ResizablePanel.displayName = "ResizablePanel"
+
+const ResizableHandle = ({
+  withHandle,
+  className,
+  ...props
+}: React.ComponentPropsWithoutRef<typeof ResizablePrimitive.Separator> & {
+  withHandle?: boolean
+}) => (
+  <ResizablePrimitive.Separator
+    className={cn(
+      "relative flex w-px items-center justify-center bg-border after:absolute after:inset-y-0 after:left-1/2 after:w-1 after:-translate-x-1/2 focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring focus-visible:ring-offset-1 data-[panel-group-direction=vertical]:h-px data-[panel-group-direction=vertical]:w-full data-[panel-group-direction=vertical]:after:left-0 data-[panel-group-direction=vertical]:after:h-1 data-[panel-group-direction=vertical]:after:w-full data-[panel-group-direction=vertical]:after:-translate-y-1/2 data-[panel-group-direction=vertical]:after:translate-x-0 [&[data-panel-group-direction=vertical]>div]:rotate-90",
+      className
+    )}
+    {...props}
+  >
+    {withHandle && (
+      <div className="z-10 flex h-4 w-3 items-center justify-center rounded-sm border bg-border">
+        <GripVertical className="h-2.5 w-2.5" />
+      </div>
+    )}
+  </ResizablePrimitive.Separator>
+)
+ResizableHandle.displayName = "ResizableHandle"
+
+export { ResizablePanelGroup, ResizablePanel, ResizableHandle }

src/renderer/components/ui/scroll-area.tsx

@@ -0,0 +1,47 @@
+"use client"
+
+import * as React from "react"
+import * as ScrollAreaPrimitive from "@radix-ui/react-scroll-area"
+
+import { cn } from "@/lib/utils"
+
+const ScrollArea = React.forwardRef<
+  React.ElementRef<typeof ScrollAreaPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof ScrollAreaPrimitive.Root>
+>(({ className, children, ...props }, ref) => (
+  <ScrollAreaPrimitive.Root
+    ref={ref}
+    className={cn("relative overflow-hidden", className)}
+    {...props}
+  >
+    <ScrollAreaPrimitive.Viewport className="h-full w-full rounded-[inherit]">
+      {children}
+    </ScrollAreaPrimitive.Viewport>
+    <ScrollBar />
+    <ScrollAreaPrimitive.Corner />
+  </ScrollAreaPrimitive.Root>
+))
+ScrollArea.displayName = ScrollAreaPrimitive.Root.displayName
+
+const ScrollBar = React.forwardRef<
+  React.ElementRef<typeof ScrollAreaPrimitive.ScrollAreaScrollbar>,
+  React.ComponentPropsWithoutRef<typeof ScrollAreaPrimitive.ScrollAreaScrollbar>
+>(({ className, orientation = "vertical", ...props }, ref) => (
+  <ScrollAreaPrimitive.ScrollAreaScrollbar
+    ref={ref}
+    orientation={orientation}
+    className={cn(
+      "flex touch-none select-none transition-colors",
+      orientation === "vertical" &&
+        "h-full w-2.5 border-l border-l-transparent p-[1px]",
+      orientation === "horizontal" &&
+        "h-2.5 flex-col border-t border-t-transparent p-[1px]",
+      className
+    )}
+    {...props}
+  >
+    <ScrollAreaPrimitive.ScrollAreaThumb className="relative flex-1 rounded-full bg-border" />
+  </ScrollAreaPrimitive.ScrollAreaScrollbar>
+))
+ScrollBar.displayName = ScrollAreaPrimitive.ScrollAreaScrollbar.displayName
+export { ScrollArea, ScrollBar }

src/renderer/components/ui/select.tsx

@@ -0,0 +1,159 @@
+"use client"
+
+import * as React from "react"
+import * as SelectPrimitive from "@radix-ui/react-select"
+import { Check, ChevronDown, ChevronUp } from "lucide-react"
+import { cn } from "@/lib/utils"
+
+const Select = SelectPrimitive.Root
+
+const SelectGroup = SelectPrimitive.Group
+
+const SelectValue = SelectPrimitive.Value
+
+const SelectTrigger = React.forwardRef<
+  React.ElementRef<typeof SelectPrimitive.Trigger>,
+  React.ComponentPropsWithoutRef<typeof SelectPrimitive.Trigger>
+>(({ className, children, ...props }, ref) => (
+  <SelectPrimitive.Trigger
+    ref={ref}
+    className={cn(
+      "flex h-10 w-full items-center justify-between rounded-md border border-input bg-background px-3 py-2 text-sm ring-offset-background placeholder:text-muted-foreground focus:outline-none focus:ring-2 focus:ring-ring focus:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50 [&>span]:line-clamp-1",
+      className
+    )}
+    {...props}
+  >
+    {children}
+    <SelectPrimitive.Icon asChild>
+      <ChevronDown className="h-4 w-4 opacity-50" />
+    </SelectPrimitive.Icon>
+  </SelectPrimitive.Trigger>
+))
+SelectTrigger.displayName = SelectPrimitive.Trigger.displayName
+
+const SelectScrollUpButton = React.forwardRef<
+  React.ElementRef<typeof SelectPrimitive.ScrollUpButton>,
+  React.ComponentPropsWithoutRef<typeof SelectPrimitive.ScrollUpButton>
+>(({ className, ...props }, ref) => (
+  <SelectPrimitive.ScrollUpButton
+    ref={ref}
+    className={cn(
+      "flex cursor-default items-center justify-center py-1",
+      className
+    )}
+    {...props}
+  >
+    <ChevronUp className="h-4 w-4" />
+  </SelectPrimitive.ScrollUpButton>
+))
+SelectScrollUpButton.displayName = SelectPrimitive.ScrollUpButton.displayName
+
+const SelectScrollDownButton = React.forwardRef<
+  React.ElementRef<typeof SelectPrimitive.ScrollDownButton>,
+  React.ComponentPropsWithoutRef<typeof SelectPrimitive.ScrollDownButton>
+>(({ className, ...props }, ref) => (
+  <SelectPrimitive.ScrollDownButton
+    ref={ref}
+    className={cn(
+      "flex cursor-default items-center justify-center py-1",
+      className
+    )}
+    {...props}
+  >
+    <ChevronDown className="h-4 w-4" />
+  </SelectPrimitive.ScrollDownButton>
+))
+SelectScrollDownButton.displayName =
+  SelectPrimitive.ScrollDownButton.displayName
+
+const SelectContent = React.forwardRef<
+  React.ElementRef<typeof SelectPrimitive.Content>,
+  React.ComponentPropsWithoutRef<typeof SelectPrimitive.Content>
+>(({ className, children, position = "popper", ...props }, ref) => (
+  <SelectPrimitive.Portal>
+    <SelectPrimitive.Content
+      ref={ref}
+      className={cn(
+        "relative z-50 max-h-96 min-w-[8rem] overflow-hidden rounded-md border bg-popover text-popover-foreground shadow-md data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2",
+        position === "popper" &&
+          "data-[side=bottom]:translate-y-1 data-[side=left]:-translate-x-1 data-[side=right]:translate-x-1 data-[side=top]:-translate-y-1",
+        className
+      )}
+      position={position}
+      {...props}
+    >
+      <SelectScrollUpButton />
+      <SelectPrimitive.Viewport
+        className={cn(
+          "p-1",
+          position === "popper" &&
+            "h-[var(--radix-select-trigger-height)] w-full min-w-[var(--radix-select-trigger-width)]"
+        )}
+      >
+        {children}
+      </SelectPrimitive.Viewport>
+      <SelectScrollDownButton />
+    </SelectPrimitive.Content>
+  </SelectPrimitive.Portal>
+))
+SelectContent.displayName = SelectPrimitive.Content.displayName
+
+const SelectLabel = React.forwardRef<
+  React.ElementRef<typeof SelectPrimitive.Label>,
+  React.ComponentPropsWithoutRef<typeof SelectPrimitive.Label>
+>(({ className, ...props }, ref) => (
+  <SelectPrimitive.Label
+    ref={ref}
+    className={cn("py-1.5 pl-8 pr-2 text-sm font-semibold", className)}
+    {...props}
+  />
+))
+SelectLabel.displayName = SelectPrimitive.Label.displayName
+
+const SelectItem = React.forwardRef<
+  React.ElementRef<typeof SelectPrimitive.Item>,
+  React.ComponentPropsWithoutRef<typeof SelectPrimitive.Item>
+>(({ className, children, ...props }, ref) => (
+  <SelectPrimitive.Item
+    ref={ref}
+    className={cn(
+      "relative flex w-full cursor-default select-none items-center rounded-sm py-1.5 pl-8 pr-2 text-sm outline-none focus:bg-accent focus:text-accent-foreground data-[disabled]:pointer-events-none data-[disabled]:opacity-50",
+      className
+    )}
+    {...props}
+  >
+    <span className="absolute left-2 flex h-3.5 w-3.5 items-center justify-center">
+      <SelectPrimitive.ItemIndicator>
+        <Check className="h-4 w-4" />
+      </SelectPrimitive.ItemIndicator>
+    </span>
+
+    <SelectPrimitive.ItemText>{children}</SelectPrimitive.ItemText>
+  </SelectPrimitive.Item>
+))
+SelectItem.displayName = SelectPrimitive.Item.displayName
+
+const SelectSeparator = React.forwardRef<
+  React.ElementRef<typeof SelectPrimitive.Separator>,
+  React.ComponentPropsWithoutRef<typeof SelectPrimitive.Separator>
+>(({ className, ...props }, ref) => (
+  <SelectPrimitive.Separator
+    ref={ref}
+    className={cn("-mx-1 my-1 h-px bg-muted", className)}
+    {...props}
+  />
+))
+SelectSeparator.displayName = SelectPrimitive.Separator.displayName
+
+export {
+  Select,
+  SelectGroup,
+  SelectValue,
+  SelectTrigger,
+  SelectContent,
+  SelectLabel,
+  SelectItem,
+  SelectSeparator,
+  SelectScrollUpButton,
+  SelectScrollDownButton,
+}

src/renderer/components/ui/sheet.tsx

@@ -0,0 +1,146 @@
+"use client"
+
+import * as React from "react"
+import * as SheetPrimitive from "@radix-ui/react-dialog"
+import { cva, type VariantProps } from "class-variance-authority"
+import { X } from "lucide-react"
+
+import { cn } from "@/lib/utils"
+
+const Sheet = SheetPrimitive.Root
+
+const SheetTrigger = SheetPrimitive.Trigger
+
+const SheetClose = SheetPrimitive.Close
+
+const SheetPortal = ({
+  className,
+  ...props
+}: SheetPrimitive.DialogPortalProps) => (
+  <SheetPrimitive.Portal className={cn(className)} {...props} />
+)
+SheetPortal.displayName = SheetPrimitive.Portal.displayName
+
+const SheetOverlay = React.forwardRef<
+  React.ElementRef<typeof SheetPrimitive.Overlay>,
+  React.ComponentPropsWithoutRef<typeof SheetPrimitive.Overlay>
+>(({ className, ...props }, ref) => (
+  <SheetPrimitive.Overlay
+    className={cn(
+      "fixed inset-0 z-50 bg-background/80 backdrop-blur-sm data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:animate-in data-[state=open]:fade-in-0",
+      className
+    )}
+    {...props}
+    ref={ref}
+  />
+))
+SheetOverlay.displayName = SheetPrimitive.Overlay.displayName
+
+const sheetVariants = cva(
+  "fixed z-50 gap-4 bg-background p-6 shadow-lg transition ease-in-out data-[state=closed]:animate-out data-[state=closed]:duration-300 data-[state=open]:animate-in data-[state=open]:duration-500",
+  {
+    variants: {
+      side: {
+        top: "inset-x-0 top-0 border-b data-[state=closed]:slide-out-to-top data-[state=open]:slide-in-from-top",
+        bottom:
+          "inset-x-0 bottom-0 border-t data-[state=closed]:slide-out-to-bottom data-[state=open]:slide-in-from-bottom",
+        left: "inset-y-0 left-0 h-full w-3/4 border-r data-[state=closed]:slide-out-to-left data-[state=open]:slide-in-from-left sm:max-w-sm",
+        right:
+          "inset-y-0 right-0 h-full w-3/4 border-l data-[state=closed]:slide-out-to-right data-[state=open]:slide-in-from-right sm:max-w-sm"
+      }
+    },
+    defaultVariants: {
+      side: "right"
+    }
+  }
+)
+
+interface SheetContentProps
+  extends React.ComponentPropsWithoutRef<typeof SheetPrimitive.Content>,
+    VariantProps<typeof sheetVariants> {}
+
+const SheetContent = React.forwardRef<
+  React.ElementRef<typeof SheetPrimitive.Content>,
+  SheetContentProps
+>(({ side = "right", className, children, ...props }, ref) => (
+  <SheetPortal>
+    <SheetOverlay />
+    <SheetPrimitive.Content
+      ref={ref}
+      className={cn(sheetVariants({ side }), className)}
+      {...props}
+    >
+      {children}
+      <SheetPrimitive.Close className="absolute top-4 right-4 rounded-sm opacity-70 ring-offset-background transition-opacity hover:opacity-100 focus:ring-2 focus:ring-ring focus:ring-offset-2 focus:outline-none disabled:pointer-events-none data-[state=open]:bg-secondary">
+        <X className="h-4 w-4" />
+        <span className="sr-only">Close</span>
+      </SheetPrimitive.Close>
+    </SheetPrimitive.Content>
+  </SheetPortal>
+))
+SheetContent.displayName = SheetPrimitive.Content.displayName
+
+const SheetHeader = ({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLDivElement>) => (
+  <div
+    className={cn(
+      "flex flex-col space-y-2 text-center sm:text-left",
+      className
+    )}
+    {...props}
+  />
+)
+SheetHeader.displayName = "SheetHeader"
+
+const SheetFooter = ({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLDivElement>) => (
+  <div
+    className={cn(
+      "flex flex-col-reverse sm:flex-row sm:justify-end sm:space-x-2",
+      className
+    )}
+    {...props}
+  />
+)
+SheetFooter.displayName = "SheetFooter"
+
+const SheetTitle = React.forwardRef<
+  React.ElementRef<typeof SheetPrimitive.Title>,
+  React.ComponentPropsWithoutRef<typeof SheetPrimitive.Title>
+>(({ className, ...props }, ref) => (
+  <SheetPrimitive.Title
+    ref={ref}
+    className={cn("text-lg font-semibold text-foreground", className)}
+    {...props}
+  />
+))
+SheetTitle.displayName = SheetPrimitive.Title.displayName
+
+const SheetDescription = React.forwardRef<
+  React.ElementRef<typeof SheetPrimitive.Description>,
+  React.ComponentPropsWithoutRef<typeof SheetPrimitive.Description>
+>(({ className, ...props }, ref) => (
+  <SheetPrimitive.Description
+    ref={ref}
+    className={cn("text-sm text-muted-foreground", className)}
+    {...props}
+  />
+))
+SheetDescription.displayName = SheetPrimitive.Description.displayName
+
+export {
+  Sheet,
+  SheetPortal,
+  SheetOverlay,
+  SheetTrigger,
+  SheetClose,
+  SheetContent,
+  SheetHeader,
+  SheetFooter,
+  SheetTitle,
+  SheetDescription
+}

src/renderer/components/ui/slider.tsx

@@ -0,0 +1,33 @@
+"use client"
+
+import * as React from "react"
+import * as SliderPrimitive from "@radix-ui/react-slider"
+import { cn } from "@/lib/utils"
+
+const Slider = React.forwardRef<
+  React.ElementRef<typeof SliderPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof SliderPrimitive.Root>
+>(({ className, ...props }, ref) => {
+  const { 'aria-label': ariaLabel, ...rest } = props;
+  return (
+    <SliderPrimitive.Root
+      ref={ref}
+      className={cn(
+        "relative flex w-full touch-none select-none items-center",
+        className
+      )}
+      {...rest}
+    >
+      <SliderPrimitive.Track className="relative h-2 w-full grow overflow-hidden rounded-full bg-secondary">
+        <SliderPrimitive.Range className="absolute h-full bg-primary" />
+      </SliderPrimitive.Track>
+      <SliderPrimitive.Thumb
+        aria-label={ariaLabel}
+        className="block h-5 w-5 rounded-full border-2 border-primary bg-background ring-offset-background transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:pointer-events-none disabled:opacity-50"
+      />
+    </SliderPrimitive.Root>
+  );
+})
+Slider.displayName = SliderPrimitive.Root.displayName
+
+export { Slider }

src/renderer/components/ui/sonner.tsx

@@ -0,0 +1,34 @@
+"use client"
+
+import { useTheme } from "next-themes"
+import { Toaster as Sonner } from "sonner"
+
+type ToasterProps = React.ComponentProps<typeof Sonner>
+
+const Toaster = ({ ...props }: ToasterProps) => {
+  const { theme = "system" } = useTheme()
+
+  return (
+    <Sonner
+      theme={theme as ToasterProps["theme"]}
+      className="toaster group"
+      toastOptions={{
+        classNames: {
+          toast:
+            "group toast group-[.toaster]:bg-background group-[.toaster]:text-foreground group-[.toaster]:border-border group-[.toaster]:shadow-lg",
+          description: "group-[.toast]:text-muted-foreground",
+          actionButton:
+            "group-[.toast]:bg-primary group-[.toast]:text-primary-foreground",
+          cancelButton:
+            "group-[.toast]:bg-muted group-[.toast]:text-muted-foreground",
+        },
+      }}
+      richColors
+      closeButton
+      position="bottom-right"
+      {...props}
+    />
+  )
+}
+
+export { Toaster }

src/renderer/components/ui/switch.tsx

@@ -0,0 +1,26 @@
+import * as React from "react"
+import * as SwitchPrimitive from "@radix-ui/react-switch"
+import { cn } from "@/lib/utils"
+
+const Switch = React.forwardRef<
+  React.ElementRef<typeof SwitchPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof SwitchPrimitive.Root>
+>(({ className, ...props }, ref) => (
+  <SwitchPrimitive.Root
+    ref={ref}
+    className={cn(
+      "peer inline-flex h-6 w-11 shrink-0 cursor-pointer items-center rounded-full border-2 border-transparent transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 focus-visible:ring-offset-background disabled:cursor-not-allowed disabled:opacity-50 data-[state=checked]:bg-primary data-[state=unchecked]:bg-input",
+      className
+    )}
+    {...props}
+  >
+    <SwitchPrimitive.Thumb
+      className={cn(
+        "pointer-events-none block h-5 w-5 rounded-full bg-background shadow-lg ring-0 transition-transform data-[state=checked]:translate-x-5 data-[state=unchecked]:translate-x-0"
+      )}
+    />
+  </SwitchPrimitive.Root>
+))
+Switch.displayName = SwitchPrimitive.Root.displayName
+
+export { Switch }

src/renderer/components/ui/tabs.tsx

@@ -0,0 +1,91 @@
+"use client"
+
+import * as React from "react"
+import { cva, type VariantProps } from "class-variance-authority"
+import * as TabsPrimitive from "@radix-ui/react-tabs"
+
+import { cn } from "@/lib/utils"
+
+function Tabs({
+  className,
+  orientation = "horizontal",
+  ...props
+}: React.ComponentProps<typeof TabsPrimitive.Root>) {
+  return (
+    <TabsPrimitive.Root
+      data-slot="tabs"
+      data-orientation={orientation}
+      orientation={orientation}
+      className={cn(
+        "group/tabs flex gap-2 data-[orientation=horizontal]:flex-col",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+const tabsListVariants = cva(
+  "group/tabs-list inline-flex w-fit items-center justify-center rounded-lg p-[3px] text-muted-foreground group-data-[orientation=horizontal]/tabs:h-9 group-data-[orientation=vertical]/tabs:h-fit group-data-[orientation=vertical]/tabs:flex-col data-[variant=line]:rounded-none",
+  {
+    variants: {
+      variant: {
+        default: "bg-muted",
+        line: "gap-1 bg-transparent",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+    },
+  }
+)
+
+function TabsList({
+  className,
+  variant = "default",
+  ...props
+}: React.ComponentProps<typeof TabsPrimitive.List> &
+  VariantProps<typeof tabsListVariants>) {
+  return (
+    <TabsPrimitive.List
+      data-slot="tabs-list"
+      data-variant={variant}
+      className={cn(tabsListVariants({ variant }), className)}
+      {...props}
+    />
+  )
+}
+
+function TabsTrigger({
+  className,
+  ...props
+}: React.ComponentProps<typeof TabsPrimitive.Trigger>) {
+  return (
+    <TabsPrimitive.Trigger
+      data-slot="tabs-trigger"
+      className={cn(
+        "relative inline-flex h-[calc(100%-1px)] flex-1 items-center justify-center gap-1.5 rounded-md border border-transparent px-2 py-1 text-sm font-medium whitespace-nowrap text-foreground/60 transition-all group-data-[orientation=vertical]/tabs:w-full group-data-[orientation=vertical]/tabs:justify-start hover:text-foreground focus-visible:border-ring focus-visible:ring-[3px] focus-visible:ring-ring/50 focus-visible:outline-1 focus-visible:outline-ring disabled:pointer-events-none disabled:opacity-50 group-data-[variant=default]/tabs-list:data-[state=active]:shadow-sm group-data-[variant=line]/tabs-list:data-[state=active]:shadow-none dark:text-muted-foreground dark:hover:text-foreground [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4",
+        "group-data-[variant=line]/tabs-list:bg-transparent group-data-[variant=line]/tabs-list:data-[state=active]:bg-transparent dark:group-data-[variant=line]/tabs-list:data-[state=active]:border-transparent dark:group-data-[variant=line]/tabs-list:data-[state=active]:bg-transparent",
+        "data-[state=active]:bg-background data-[state=active]:text-foreground dark:data-[state=active]:border-input dark:data-[state=active]:bg-input/30 dark:data-[state=active]:text-foreground",
+        "after:absolute after:bg-foreground after:opacity-0 after:transition-opacity group-data-[orientation=horizontal]/tabs:after:inset-x-0 group-data-[orientation=horizontal]/tabs:after:bottom-[-5px] group-data-[orientation=horizontal]/tabs:after:h-0.5 group-data-[orientation=vertical]/tabs:after:inset-y-0 group-data-[orientation=vertical]/tabs:after:-right-1 group-data-[orientation=vertical]/tabs:after:w-0.5 group-data-[variant=line]/tabs-list:data-[state=active]:after:opacity-100",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function TabsContent({
+  className,
+  ...props
+}: React.ComponentProps<typeof TabsPrimitive.Content>) {
+  return (
+    <TabsPrimitive.Content
+      data-slot="tabs-content"
+      className={cn("flex-1 outline-none", className)}
+      {...props}
+    />
+  )
+}
+
+export { Tabs, TabsList, TabsTrigger, TabsContent, tabsListVariants }

src/renderer/components/ui/textarea.tsx

@@ -0,0 +1,24 @@
+import * as React from "react"
+
+import { cn } from "@/lib/utils"
+
+export interface TextareaProps
+  extends React.TextareaHTMLAttributes<HTMLTextAreaElement> {}
+
+const Textarea = React.forwardRef<HTMLTextAreaElement, TextareaProps>(
+  ({ className, ...props }, ref) => {
+    return (
+      <textarea
+        className={cn(
+          "flex min-h-[80px] w-full rounded-md border border-input bg-background px-3 py-2 text-sm ring-offset-background placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50",
+          className
+        )}
+        ref={ref}
+        {...props}
+      />
+    )
+  }
+)
+Textarea.displayName = "Textarea"
+
+export { Textarea }

src/renderer/hooks/use-export-source.ts

@@ -0,0 +1,26 @@
+import { useFileStore } from '@/stores/file-store';
+import { useEditorStore } from '@/stores/editor-store';
+
+export interface ExportSource {
+  source: string;
+  path: string;
+  title: string;
+}
+
+/**
+ * Read the active buffer's content from the editor store. Returns null if
+ * no buffer is open. Components handle the null case (prompt to open a file).
+ */
+export function useExportSource(): ExportSource | null {
+  const activeTabId = useFileStore((s) => s.activeTabId);
+  const openTabs = useFileStore((s) => s.openTabs);
+  const buffer = useEditorStore((s) => (activeTabId ? s.buffers.get(activeTabId) : undefined));
+
+  if (!activeTabId || !buffer) return null;
+  const tab = openTabs.find((t) => t.id === activeTabId);
+  return {
+    source: buffer.content,
+    path: activeTabId,
+    title: tab?.title ?? activeTabId,
+  };
+}

src/renderer/hooks/use-file-shortcuts.ts

@@ -0,0 +1,72 @@
+import { useEffect } from 'react';
+import { useFileStore } from '@/stores/file-store';
+
+/**
+ * Global keyboard shortcuts for file operations.
+ *
+ * - Cmd/Ctrl+O: open file
+ * - Cmd/Ctrl+Shift+O: open folder
+ * - Cmd/Ctrl+S: save active buffer
+ * - Cmd/Ctrl+W: close active tab
+ * - Cmd/Ctrl+Tab / Cmd/Ctrl+Shift+Tab: next/previous tab (wraps)
+ *
+ * Suppressed when an <input>, <textarea>, or contentEditable element has focus.
+ */
+export function useFileShortcuts(): void {
+  useEffect(() => {
+    function isTypingTarget(target: EventTarget | null): boolean {
+      if (!(target instanceof HTMLElement)) return false;
+      const tag = target.tagName;
+      if (tag === 'INPUT' || tag === 'TEXTAREA') return true;
+      if (target.isContentEditable) return true;
+      return false;
+    }
+
+    function handle(e: KeyboardEvent): void {
+      const mod = e.metaKey || e.ctrlKey;
+      if (!mod) return;
+      if (isTypingTarget(e.target)) return;
+
+      const key = e.key.toLowerCase();
+
+      // Order matters: more specific (Shift) variants first so they don't get
+      // shadowed by the plain modifier-only branch.
+      if (e.shiftKey && key === 'o') {
+        e.preventDefault();
+        void useFileStore.getState().openFolderDialog();
+        return;
+      }
+      if (!e.shiftKey && key === 'o') {
+        e.preventDefault();
+        void useFileStore.getState().openFileDialog();
+        return;
+      }
+      if (!e.shiftKey && key === 's') {
+        e.preventDefault();
+        void useFileStore.getState().saveActiveBuffer();
+        return;
+      }
+      if (!e.shiftKey && key === 'w') {
+        e.preventDefault();
+        const { activeTabId, closeTab } = useFileStore.getState();
+        if (activeTabId) closeTab(activeTabId);
+        return;
+      }
+      if (key === 'tab') {
+        e.preventDefault();
+        const { openTabs, activeTabId, setActiveTab } = useFileStore.getState();
+        if (openTabs.length === 0) return;
+        const idx = activeTabId ? openTabs.findIndex((t) => t.id === activeTabId) : 0;
+        const safeIdx = idx === -1 ? 0 : idx;
+        const nextIdx = e.shiftKey
+          ? (safeIdx <= 0 ? openTabs.length - 1 : safeIdx - 1)
+          : (safeIdx >= openTabs.length - 1 ? 0 : safeIdx + 1);
+        setActiveTab(openTabs[nextIdx].id);
+        return;
+      }
+    }
+
+    window.addEventListener('keydown', handle);
+    return () => window.removeEventListener('keydown', handle);
+  }, []);
+}

src/renderer/hooks/use-menu-action.ts

@@ -0,0 +1,29 @@
+import { useEffect } from 'react';
+import { ipc } from '@/lib/ipc';
+import { useCommandStore } from '@/stores/command-store';
+import type { CommandId } from '@/stores/command-store';
+
+type Transform<Args = unknown> = (...payload: unknown[]) => Args;
+
+/**
+ * Bridge a native-menu IPC channel to a command-store dispatch.
+ *
+ * When the main process sends `channel` (e.g. `'file-save'`), the optional
+ * `transform` converts the payload to the command's args, then the command
+ * `commandId` is dispatched through the command store.
+ *
+ * The hook cleans up its IPC subscription on unmount.
+ */
+export function useMenuAction<Args = unknown>(
+  channel: string,
+  commandId: CommandId,
+  transform?: Transform<Args>
+): void {
+  useEffect(() => {
+    const unsubscribe = ipc.menu.on(channel, (...payload: unknown[]) => {
+      const args = transform ? transform(...payload) : (payload[0] as Args);
+      useCommandStore.getState().dispatch(commandId, args);
+    });
+    return unsubscribe;
+  }, [channel, commandId, transform]);
+}

src/renderer/hooks/use-restore-last-folder.ts

@@ -0,0 +1,18 @@
+import { useEffect } from 'react';
+import { useFileStore } from '@/stores/file-store';
+
+/**
+ * On mount, re-opens the last folder if one was persisted via the file store's
+ * zustand persist middleware. Idempotent — re-running with the same path is a
+ * no-op (openFolder's list IPC call would just re-fetch, which is acceptable).
+ */
+export function useRestoreLastFolder(): void {
+  useEffect(() => {
+    const { rootPath, openFolder, tree } = useFileStore.getState();
+    if (rootPath && !tree) {
+      void openFolder(rootPath);
+    }
+    // Run once on mount only. Persist hydration happens before AppShell renders.
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+}

src/renderer/hooks/use-scroll-sync.ts

@@ -0,0 +1,28 @@
+import { useCallback, useRef } from 'react';
+
+interface Options {
+  onEditorScroll?: (ratio: number) => void;
+  onPreviewScroll?: (ratio: number) => void;
+}
+
+export function useScrollSync(opts: Options) {
+  const FRAME_MS = 1000 / 60;
+  const lastTick = useRef(-FRAME_MS);
+
+  const handleEditorScroll = useCallback((evt: React.UIEvent<HTMLElement>) => {
+    const target = evt.currentTarget;
+    const ratio = target.scrollTop / Math.max(target.scrollHeight - target.clientHeight, 1);
+    const now = performance.now();
+    if (now - lastTick.current < FRAME_MS) return;
+    lastTick.current = now;
+    opts.onEditorScroll?.(ratio);
+  }, [opts]);
+
+  const handlePreviewScroll = useCallback((evt: React.UIEvent<HTMLElement>) => {
+    const target = evt.currentTarget;
+    const ratio = target.scrollTop / Math.max(target.scrollHeight - target.clientHeight, 1);
+    opts.onPreviewScroll?.(ratio);
+  }, [opts]);
+
+  return { handleEditorScroll, handlePreviewScroll };
+}

src/renderer/hooks/use-shortcut.ts

@@ -0,0 +1,96 @@
+import { useEffect } from 'react';
+
+/**
+ * Bind a keyboard shortcut to a callback.
+ *
+ * Combos use `+` separators. Tokens:
+ *   - `mod`         → meta (Mac) or ctrl (others)
+ *   - `ctrl`        → ctrl only
+ *   - `meta`        → meta only
+ *   - `alt`         → alt / option
+ *   - `shift`       → shift
+ *   - any single char (case-insensitive), e.g. `s`, `S`
+ *   - special names: `Tab`, `Enter`, `Escape`, `Space`, `ArrowUp/Down/Left/Right`
+ *
+ * The hook is suppressed when the keydown target is an `<input>`, `<textarea>`,
+ * or contentEditable element, mirroring the standard browser shortcut pattern.
+ *
+ * On match, `event.preventDefault()` is called.
+ */
+export function useShortcut(combo: string, callback: (e: KeyboardEvent) => void): void {
+  useEffect(() => {
+    const tokens = parseCombo(combo);
+
+    function isTypingTarget(target: EventTarget | null): boolean {
+      if (!(target instanceof HTMLElement)) return false;
+      const tag = target.tagName;
+      if (tag === 'INPUT' || tag === 'TEXTAREA') return true;
+      if (target.isContentEditable) return true;
+      return false;
+    }
+
+    function handle(e: KeyboardEvent): void {
+      if (isTypingTarget(e.target)) return;
+      if (!matchCombo(tokens, e)) return;
+      e.preventDefault();
+      callback(e);
+    }
+
+    window.addEventListener('keydown', handle);
+    return () => window.removeEventListener('keydown', handle);
+  }, [combo, callback]);
+}
+
+interface ComboSpec {
+  mod?: boolean;
+  ctrl?: boolean;
+  meta?: boolean;
+  alt?: boolean;
+  shift?: boolean;
+  key: string; // lowercased
+}
+
+function parseCombo(combo: string): ComboSpec {
+  const parts = combo
+    .split('+')
+    .map((p) => p.trim())
+    .filter(Boolean);
+  const spec: ComboSpec = { key: '' };
+  for (const p of parts) {
+    const lower = p.toLowerCase();
+    if (lower === 'mod') spec.mod = true;
+    else if (lower === 'ctrl' || lower === 'control') spec.ctrl = true;
+    else if (lower === 'meta' || lower === 'cmd' || lower === 'command') spec.meta = true;
+    else if (lower === 'alt' || lower === 'option') spec.alt = true;
+    else if (lower === 'shift') spec.shift = true;
+    else spec.key = lower;
+  }
+  return spec;
+}
+
+function matchCombo(spec: ComboSpec, e: KeyboardEvent): boolean {
+  const key = e.key.toLowerCase();
+  if (key !== spec.key) return false;
+
+  if (spec.mod) {
+    if (!(e.metaKey || e.ctrlKey)) return false;
+  }
+  if (spec.ctrl && !e.ctrlKey) return false;
+  if (spec.meta && !e.metaKey) return false;
+  if (spec.alt && !e.altKey) return false;
+  if (spec.shift && !e.shiftKey) return false;
+
+  // Reject extra modifiers that the spec did not ask for.
+  // (e.g. spec says "mod+s" but user pressed "mod+shift+s" → no match.)
+  if (!spec.shift && e.shiftKey) return false;
+  if (!spec.alt && e.altKey) return false;
+  // ctrl/meta: if spec did not require mod, ctrl or meta must be absent.
+  if (!spec.mod && !spec.ctrl && e.ctrlKey) return false;
+  if (!spec.mod && !spec.meta && e.metaKey) return false;
+  // If spec said "mod" only, ctrl+meta is allowed (mod is either-or).
+  if (spec.mod && !spec.ctrl && !spec.meta) {
+    // ok
+  }
+
+  return true;
+}

src/renderer/hooks/use-welcome-trigger.ts

@@ -0,0 +1,15 @@
+import { useEffect } from 'react';
+import { useAppStore } from '@/stores/app-store';
+import { useSettingsStore } from '@/stores/settings-store';
+
+/**
+ * On first mount, if the user hasn't dismissed the welcome dialog, open it.
+ * Call once at the top of App.tsx.
+ */
+export function useWelcomeTrigger() {
+  useEffect(() => {
+    if (!useSettingsStore.getState().welcomeDismissed) {
+      useAppStore.getState().openModal('welcome');
+    }
+  }, []);
+}

src/renderer/index.html

@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8">
+  <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self' data:; connect-src 'self';">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <title>MarkdownConverter</title>
+  <link rel="preconnect" href="https://fonts.googleapis.com">
+  <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
+  <link href="https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600;700&display=swap" rel="stylesheet">
+</head>
+<body class="font-sans antialiased">
+  <div id="root"></div>
+  <script type="module" src="./main.tsx"></script>
+</body>
+</html>

src/renderer/lib/ascii-table.ts

@@ -0,0 +1,44 @@
+/**
+ * Convert a 2D string array to a fixed-width ASCII table with `| ... |` rows
+ * and a `| --- |` separator.
+ */
+export function toAsciiTable(rows: string[][]): string {
+  if (rows.length === 0) return '';
+  const numCols = Math.max(...rows.map((r) => r.length));
+  const widths: number[] = Array.from({ length: numCols }, (_, c) =>
+    Math.max(...rows.map((r) => (r[c] ?? '').length))
+  );
+  // Heuristic: if ANY column header starts with a digit, right-align ALL columns
+  const header = rows[0];
+  const rightAlign = header.some((cell) => /^\d/.test(cell));
+  const pad = rightAlign
+    ? (s: string, w: number) => s.padStart(w)
+    : (s: string, w: number) => s.padEnd(w);
+  const lines = rows.map((row) =>
+    '| ' +
+    Array.from({ length: numCols }, (_, c) => pad(row[c] ?? '', widths[c])).join(' | ') +
+    ' |'
+  );
+  // Insert separator after first row
+  const sep =
+    '| ' + Array.from({ length: numCols }, (_, c) => '-'.repeat(widths[c])).join(' | ') + ' |';
+  return [lines[0], sep, ...lines.slice(1)].join('\n');
+}
+
+// Matches a markdown table block: header row, separator, ≥1 data row.
+const TABLE_RE = /^\|.+\|\n^\|[\s:|-]+\|\n((?:^\|.+\|\n?)+)/gm;
+
+/**
+ * Replace all markdown tables in `source` with fenced code blocks containing
+ * the ASCII-rendered equivalent. Non-table content is preserved verbatim.
+ */
+export function applyAsciiTransform(source: string): string {
+  return source.replace(TABLE_RE, (block) => {
+    const lines = block.trim().split('\n');
+    const header = lines[0].slice(1, -1).split('|').map((s) => s.trim());
+    const body = lines.slice(2).map((l) =>
+      l.slice(1, -1).split('|').map((s) => s.trim())
+    );
+    return '```\n' + toAsciiTable([header, ...body]) + '\n```';
+  });
+}

src/renderer/lib/commands/register-menu-commands.ts

@@ -0,0 +1,112 @@
+import { useEffect } from 'react';
+import { useCommandStore } from '@/stores/command-store';
+import { useFileStore } from '@/stores/file-store';
+import { useAppStore } from '@/stores/app-store';
+import { useMenuAction } from '@/hooks/use-menu-action';
+
+/**
+ * Register all Phase 6 menu commands in the command store, and bridge
+ * the native menu IPC channels to the matching command ids.
+ *
+ * Phase 6 scope: file/view/tab commands with direct store mappings.
+ * Phase 7+ will add the dialog-driven commands (export, settings, etc.)
+ * once the corresponding modals exist.
+ */
+export function registerMenuCommands(): void {
+  const { registerMany } = useCommandStore.getState();
+
+  registerMany({
+    'settings.open': () => useAppStore.getState().openModal('settings'),
+    'help.about': () => useAppStore.getState().openModal('about'),
+    'help.welcome': () => useAppStore.getState().openModal('welcome'),
+    'file.exportPdf': () => {
+      const activeTabId = useFileStore.getState().activeTabId;
+      if (!activeTabId) return;
+      useAppStore.getState().openModal('export-pdf', { sourcePath: activeTabId });
+    },
+    'file.exportDocx': () => {
+      const activeTabId = useFileStore.getState().activeTabId;
+      if (!activeTabId) return;
+      useAppStore.getState().openModal('export-docx', { sourcePath: activeTabId });
+    },
+    'file.exportHtml': () => {
+      const activeTabId = useFileStore.getState().activeTabId;
+      if (!activeTabId) return;
+      useAppStore.getState().openModal('export-html', { sourcePath: activeTabId });
+    },
+    'file.exportBatch': () => {
+      const paths = useFileStore.getState().openTabs.map((t) => t.path);
+      if (paths.length === 0) return;
+      useAppStore.getState().openModal('export-batch', { sourcePaths: paths });
+    },
+    'file.confirmClose': () => {
+      /* stub — wired in later phase */
+    },
+    'app.quit': () => {
+      /* stub — wired in later phase */
+    },
+  });
+
+  const { register } = useCommandStore.getState();
+  register('file.open', () => {
+    void useFileStore.getState().openFileDialog();
+  });
+  register('file.openFolder', () => {
+    void useFileStore.getState().openFolderDialog();
+  });
+  register('file.save', () => {
+    void useFileStore.getState().saveActiveBuffer();
+  });
+  register('file.closeTab', () => {
+    const { activeTabId, closeTab } = useFileStore.getState();
+    if (activeTabId) closeTab(activeTabId);
+  });
+  register('tab.next', () => {
+    const { openTabs, activeTabId, setActiveTab } = useFileStore.getState();
+    if (openTabs.length === 0) return;
+    const idx = activeTabId ? openTabs.findIndex((t) => t.id === activeTabId) : 0;
+    const safeIdx = idx === -1 ? 0 : idx;
+    const nextIdx = safeIdx >= openTabs.length - 1 ? 0 : safeIdx + 1;
+    setActiveTab(openTabs[nextIdx].id);
+  });
+  register('tab.prev', () => {
+    const { openTabs, activeTabId, setActiveTab } = useFileStore.getState();
+    if (openTabs.length === 0) return;
+    const idx = activeTabId ? openTabs.findIndex((t) => t.id === activeTabId) : 0;
+    const safeIdx = idx === -1 ? 0 : idx;
+    const nextIdx = safeIdx <= 0 ? openTabs.length - 1 : safeIdx - 1;
+    setActiveTab(openTabs[nextIdx].id);
+  });
+  register('view.toggleSidebar', () => useAppStore.getState().toggleSidebar());
+  register('view.togglePreview', () => useAppStore.getState().togglePreview());
+}
+
+export function useRegisterMenuCommands(): void {
+  // Register handlers in the command store.
+  useEffect(() => {
+    registerMenuCommands();
+  }, []);
+}
+
+/**
+ * Wire native-menu IPC channels to the command store.
+ * Channel names match what main.js dispatches via webContents.send.
+ */
+export function useBridgeNativeMenu(): void {
+  useMenuAction('file-save', 'file.save');
+  useMenuAction('toggle-preview', 'view.togglePreview');
+  useMenuAction('toggle-command-palette', 'command.palette');
+  useMenuAction('toggle-sidebar-panel', 'view.sidebarPanel', (panel) => panel as string);
+  useMenuAction('toggle-bottom-panel', 'view.bottomPanel');
+  useMenuAction('toggle-find', 'find.toggle');
+  useMenuAction('undo', 'editor.undo');
+  useMenuAction('redo', 'editor.redo');
+  useMenuAction('adjust-font-size', 'font.size', (direction) => direction as string);
+  useMenuAction('load-custom-css', 'theme.loadCustomCss');
+  useMenuAction('clear-custom-css', 'theme.clearCustomCss');
+  useMenuAction('load-template-menu', 'template.load', (name) => name as string);
+  useMenuAction('print-preview', 'print.preview');
+  useMenuAction('print-preview-styled', 'print.previewStyled');
+  useMenuAction('file-opened', 'file.opened', (payload) => payload);
+  useMenuAction('clear-recent-files', 'file.clearRecent');
+}

src/renderer/lib/ipc.ts

@@ -0,0 +1,110 @@
+import type {
+  IpcResult,
+  FileResult,
+  FileEntry,
+  PdfOptions,
+  DocxOptions,
+  HtmlOptions,
+  ExportResult,
+  BatchItem,
+  BatchOptions,
+  BatchResult,
+} from '@/types/ipc';
+
+type ChannelMissing = { code: 'CHANNEL_MISSING'; message: string };
+
+function wrap<T>(fn: () => Promise<T>): Promise<IpcResult<T | ChannelMissing>> {
+  if (typeof window === 'undefined' || !window.electronAPI) {
+    return Promise.resolve({
+      ok: false,
+      error: { code: 'NO_BRIDGE', message: 'window.electronAPI is unavailable' },
+    });
+  }
+  return fn().then(
+    (data) => ({ ok: true as const, data }),
+    (err: Error) => ({
+      ok: false as const,
+      error: { code: err.name || 'IPC_ERROR', message: err.message || String(err) },
+    }),
+  );
+}
+
+function safeCall<T extends (...args: any[]) => Promise<any>>(
+  channel: string,
+  method: string,
+  ...args: Parameters<T>
+): Promise<IpcResult<Awaited<ReturnType<T>> | ChannelMissing>> {
+  if (typeof window === 'undefined' || !window.electronAPI) {
+    return Promise.resolve({
+      ok: false,
+      error: { code: 'NO_BRIDGE', message: 'window.electronAPI is unavailable' },
+    });
+  }
+  const target = (window.electronAPI as any)[channel]?.[method];
+  if (!target) {
+    return Promise.resolve({
+      ok: false,
+      error: { code: 'CHANNEL_MISSING', message: `Missing channel: ${channel}.${method}` },
+    });
+  }
+  if (typeof target !== 'function') {
+    return Promise.resolve({
+      ok: false,
+      error: { code: 'CHANNEL_MISSING', message: `Not a function: ${channel}.${method}` },
+    });
+  }
+  return wrap(() => target(...args));
+}
+
+export const ipc = {
+  file: {
+    open: (): Promise<IpcResult<FileResult | ChannelMissing>> =>
+      safeCall('file', 'open'),
+    read: (path: string): Promise<IpcResult<string | ChannelMissing>> =>
+      safeCall('file', 'read', path),
+    write: (path: string, content: string): Promise<IpcResult<void | ChannelMissing>> =>
+      safeCall('file', 'write', path, content),
+    list: (dir: string): Promise<IpcResult<FileEntry[] | ChannelMissing>> =>
+      safeCall('file', 'list', dir),
+    pickFolder: (): Promise<IpcResult<string | null | ChannelMissing>> =>
+      safeCall('file', 'pickFolder'),
+    pickFile: (): Promise<IpcResult<string | null | ChannelMissing>> =>
+      safeCall('file', 'pickFile'),
+    onChange: (cb: (path: string) => void): (() => void) => {
+      if (typeof window === 'undefined' || !window.electronAPI?.file?.onChange) {
+        return () => {};
+      }
+      return window.electronAPI.file.onChange(cb);
+    },
+  },
+  export: {
+    pdf: (opts: PdfOptions): Promise<IpcResult<ExportResult | ChannelMissing>> =>
+      safeCall('export', 'pdf', opts),
+    docx: (opts: DocxOptions): Promise<IpcResult<ExportResult | ChannelMissing>> =>
+      safeCall('export', 'docx', opts),
+    html: (opts: HtmlOptions): Promise<IpcResult<ExportResult | ChannelMissing>> =>
+      safeCall('export', 'html', opts),
+    batch: (items: BatchItem[], opts: BatchOptions): Promise<IpcResult<BatchResult | ChannelMissing>> =>
+      safeCall('export', 'batch', items, opts),
+  },
+  app: {
+    getVersion: (): Promise<IpcResult<string | ChannelMissing>> =>
+      safeCall('app', 'getVersion'),
+    openExternal: (url: string): Promise<IpcResult<void | ChannelMissing>> =>
+      safeCall('app', 'openExternal', url),
+    showItemInFolder: (path: string): Promise<IpcResult<void | ChannelMissing>> =>
+      safeCall('app', 'showItemInFolder', path),
+  },
+  menu: {
+    /**
+     * Subscribe to a native-menu IPC channel. The callback receives the
+     * raw payload(s) from the main process. Returns an unsubscribe fn.
+     */
+    on: (channel: string, callback: (...args: unknown[]) => void): (() => void) => {
+      if (typeof window === 'undefined' || !window.electronAPI?.on) {
+        return () => {};
+      }
+      return window.electronAPI.on(channel, callback as (...a: any[]) => void);
+    },
+  },
+};

src/renderer/lib/markdown.ts

@@ -0,0 +1,29 @@
+import { marked } from 'marked';
+import DOMPurify from 'dompurify';
+
+marked.setOptions({
+  gfm: true,
+  breaks: false,
+});
+
+const MERMAID_RE = /```mermaid\n([\s\S]*?)```/g;
+
+export function renderMarkdown(source: string): string {
+  // Mark mermaid blocks with a placeholder we can replace client-side.
+  const placeholders: string[] = [];
+  const withPlaceholders = source.replace(MERMAID_RE, (_m, code) => {
+    const idx = placeholders.length;
+    placeholders.push(code.trim());
+    return `<div class="mermaid-block" data-mermaid-source="${idx}"></div>`;
+  });
+
+  const rawHtml = marked.parse(withPlaceholders, { async: false }) as string;
+  const clean = DOMPurify.sanitize(rawHtml, {
+    ALLOWED_ATTR: ['href', 'src', 'alt', 'title', 'class', 'data-mermaid-source', 'data-language', 'id'],
+  });
+
+  // The sanitized HTML still has placeholders; we leave the actual mermaid
+  // rendering to the React layer (MermaidLazy component) so the heavy
+  // mermaid library only loads when needed.
+  return clean;
+}

src/renderer/lib/motion.ts

@@ -0,0 +1,41 @@
+import type { Transition, Variants } from 'motion/react';
+
+export const fadeIn: Transition = {
+  duration: 0.2,
+  ease: 'easeOut',
+};
+
+export const slideInRight: Variants = {
+  x: '100%',
+  initial: { x: '100%', opacity: 0 },
+  animate: { x: 0, opacity: 1, transition: { duration: 0.3, ease: [0.16, 1, 0.3, 1] } },
+  exit: { x: '100%', opacity: 0, transition: { duration: 0.2, ease: 'easeIn' } },
+};
+
+export const modalPop: Variants = {
+  scale: 0.96,
+  opacity: 0,
+  initial: { scale: 0.96, opacity: 0 },
+  animate: { scale: 1, opacity: 1, transition: { duration: 0.2, ease: 'easeOut' } },
+  exit: { scale: 0.96, opacity: 0, transition: { duration: 0.15, ease: 'easeIn' } },
+};
+
+export const toastSpring: Transition = {
+  type: 'spring',
+  stiffness: 300,
+  damping: 30,
+};
+
+export const sidebarToggle: Transition = {
+  duration: 0.25,
+  ease: 'easeInOut',
+  width: {
+    duration: 0.25,
+    ease: 'easeInOut',
+  },
+};
+
+export const tabSwitch: Transition = {
+  duration: 0.2,
+  ease: 'easeOut',
+};

src/renderer/lib/toast.ts

@@ -0,0 +1,22 @@
+import { toast as sonnerToast } from 'sonner';
+
+/**
+ * Typed wrappers over sonner's toast API. Centralizing the import gives us
+ * a single surface to evolve (e.g., add brand colors, action buttons,
+ * analytics) without touching every call site.
+ */
+export const toast = {
+  success: (message: string) => sonnerToast.success(message),
+  error: (message: string) => sonnerToast.error(message),
+  info: (message: string) => sonnerToast.info(message),
+  warning: (message: string) => sonnerToast.warning(message),
+  promise: <T>(
+    promise: Promise<T>,
+    msgs: {
+      loading: string;
+      success: string | ((data: T) => string);
+      error: string | ((err: unknown) => string);
+    }
+  ) => sonnerToast.promise(promise, msgs),
+  dismiss: (id?: string | number) => sonnerToast.dismiss(id),
+};

src/renderer/lib/utils.ts

@@ -0,0 +1,6 @@
+import { clsx, type ClassValue } from 'clsx';
+import { twMerge } from 'tailwind-merge';
+
+export function cn(...inputs: ClassValue[]): string {
+  return twMerge(clsx(inputs));
+}

src/renderer/lib/validators.ts

@@ -0,0 +1,48 @@
+import { z } from 'zod';
+
+export const settingsSchema = z.object({
+  fontSize: z.number().min(10).max(24).default(14),
+  tabSize: z.union([z.literal(2), z.literal(4), z.literal(8)]).default(4),
+  lineNumbers: z.boolean().default(true),
+  wordWrap: z.boolean().default(true),
+  minimap: z.boolean().default(true),
+  theme: z.enum(['light', 'dark', 'auto']).default('auto'),
+  accentColor: z.enum(['brand', 'blue', 'green', 'purple', 'orange']).default('brand'),
+  fontFamily: z.enum(['system', 'jetbrains', 'fira']).default('system'),
+  pdfFormat: z.enum(['letter', 'a4', 'legal']).default('a4'),
+  pdfMargins: z.enum(['normal', 'narrow', 'wide']).default('normal'),
+  pdfEmbedFonts: z.boolean().default(true),
+  docxTemplate: z.enum(['standard', 'minimal', 'modern']).default('standard'),
+  htmlHighlightStyle: z.enum(['github', 'monokai', 'nord', 'none']).default('github'),
+  renderTablesAsAscii: z.boolean().default(false),
+  welcomeDismissed: z.boolean().default(false),
+});
+export type Settings = z.infer<typeof settingsSchema>;
+
+export const exportPdfSchema = z.object({
+  format: z.enum(['letter', 'a4', 'legal']),
+  margins: z.enum(['normal', 'narrow', 'wide']),
+  embedFonts: z.boolean(),
+  renderTablesAsAscii: z.boolean().optional(),
+});
+export type ExportPdfOptions = z.infer<typeof exportPdfSchema>;
+
+export const exportDocxSchema = z.object({
+  template: z.enum(['standard', 'minimal', 'modern']),
+  renderTablesAsAscii: z.boolean().optional(),
+});
+export type ExportDocxOptions = z.infer<typeof exportDocxSchema>;
+
+export const exportHtmlSchema = z.object({
+  standalone: z.boolean(),
+  highlightStyle: z.enum(['github', 'monokai', 'nord', 'none']),
+  renderTablesAsAscii: z.boolean().optional(),
+});
+export type ExportHtmlOptions = z.infer<typeof exportHtmlSchema>;
+
+export const exportBatchSchema = z.object({
+  format: z.enum(['pdf', 'docx', 'html', 'png']),
+  concurrency: z.number().int().min(1).max(16),
+  filePaths: z.array(z.string()).min(1),
+});
+export type ExportBatchOptions = z.infer<typeof exportBatchSchema>;

src/renderer/main.tsx

@@ -0,0 +1,13 @@
+import React from 'react';
+import ReactDOM from 'react-dom/client';
+import App from './App';
+import { ThemeProvider } from './components/theme-provider';
+import './styles/globals.css';
+
+ReactDOM.createRoot(document.getElementById('root')!).render(
+  <React.StrictMode>
+    <ThemeProvider defaultTheme="dark" attribute="class" enableSystem>
+      <App />
+    </ThemeProvider>
+  </React.StrictMode>
+);

src/renderer/stores/app-store.ts

@@ -0,0 +1,80 @@
+import { create } from 'zustand';
+import { persist } from 'zustand/middleware';
+
+export interface PaneSizes {
+  sidebar: number;
+  editor: number;
+  preview: number;
+}
+
+export interface ConfirmProps {
+  title: string;
+  body: string;
+  confirmLabel?: string;
+  cancelLabel?: string;
+  destructive?: boolean;
+  onConfirm: () => void | Promise<void>;
+  onCancel?: () => void;
+}
+
+export type ModalState =
+  | { kind: null }
+  | { kind: 'export-pdf'; props: { sourcePath: string } }
+  | { kind: 'export-docx'; props: { sourcePath: string } }
+  | { kind: 'export-html'; props: { sourcePath: string } }
+  | { kind: 'export-batch'; props: { sourcePaths: string[] } }
+  | { kind: 'settings' }
+  | { kind: 'about' }
+  | { kind: 'welcome' }
+  | { kind: 'confirm'; props: ConfirmProps };
+
+export type ModalKind = ModalState['kind'];
+
+interface AppState {
+  sidebarVisible: boolean;
+  previewVisible: boolean;
+  zenMode: boolean;
+  paneSizes: PaneSizes;
+  modal: ModalState;
+  toggleSidebar: () => void;
+  togglePreview: () => void;
+  setZenMode: (value: boolean) => void;
+  setPaneSizes: (sizes: PaneSizes) => void;
+  openModal: <K extends NonNullable<ModalKind>>(
+    kind: K,
+    ...args: Extract<ModalState, { kind: K }> extends { props: infer P } ? [props?: P] : []
+  ) => void;
+  closeModal: () => void;
+}
+
+export const useAppStore = create<AppState>()(
+  persist(
+    (set) => ({
+      sidebarVisible: true,
+      previewVisible: true,
+      zenMode: false,
+      paneSizes: { sidebar: 20, editor: 50, preview: 30 },
+      modal: { kind: null },
+      toggleSidebar: () => set((s) => ({ sidebarVisible: !s.sidebarVisible })),
+      togglePreview: () => set((s) => ({ previewVisible: !s.previewVisible })),
+      setZenMode: (value) => set({ zenMode: value }),
+      setPaneSizes: (sizes) => set({ paneSizes: sizes }),
+      openModal: (kind, ...args) =>
+        set(() => {
+          const candidate = { kind, ...(args[0] ? { props: args[0] } : {}) } as ModalState;
+          return { modal: candidate };
+        }),
+      closeModal: () => set({ modal: { kind: null } }),
+    }),
+    {
+      name: 'mc-app-store',
+      partialize: (state) => ({
+        sidebarVisible: state.sidebarVisible,
+        previewVisible: state.previewVisible,
+        zenMode: state.zenMode,
+        paneSizes: state.paneSizes,
+        // modal is intentionally NOT persisted (runtime-only)
+      }),
+    }
+  )
+);

src/renderer/stores/command-store.ts

@@ -0,0 +1,66 @@
+import { create } from 'zustand';
+import { persist } from 'zustand/middleware';
+
+export type CommandId = string;
+
+export type CommandHandler = (args?: unknown) => void | Promise<void>;
+
+/**
+ * User-customizable key binding for a command.
+ * Format: same as useShortcut combo ('mod+s', 'mod+shift+s', etc.)
+ * Undefined means "use the default binding" (if any).
+ */
+export type UserBindings = Record<string, string>;
+
+interface CommandState {
+  handlers: Record<string, CommandHandler>;
+  userBindings: UserBindings;
+  register: (id: CommandId, handler: CommandHandler) => void;
+  registerMany: (handlers: Record<string, CommandHandler>) => void;
+  unregister: (id: CommandId) => void;
+  dispatch: (id: CommandId, args?: unknown) => void;
+  get: (id: CommandId) => CommandHandler | undefined;
+  setUserBinding: (id: CommandId, combo: string) => void;
+  clearUserBinding: (id: CommandId) => void;
+  getUserBinding: (id: CommandId) => string | undefined;
+}
+
+export const useCommandStore = create<CommandState>()(
+  persist(
+    (set, get) => ({
+      handlers: {},
+      userBindings: {},
+      register: (id, handler) =>
+        set((s) => ({ handlers: { ...s.handlers, [id]: handler } })),
+      registerMany: (handlers) =>
+        set((s) => ({ handlers: { ...s.handlers, ...handlers } })),
+      unregister: (id) =>
+        set((s) => {
+          const next = { ...s.handlers };
+          delete next[id];
+          return { handlers: next };
+        }),
+      dispatch: (id, args) => {
+        const handler = get().handlers[id];
+        if (handler) {
+          void handler(args);
+        }
+      },
+      get: (id) => get().handlers[id],
+      setUserBinding: (id, combo) =>
+        set((s) => ({ userBindings: { ...s.userBindings, [id]: combo } })),
+      clearUserBinding: (id) =>
+        set((s) => {
+          const next = { ...s.userBindings };
+          delete next[id];
+          return { userBindings: next };
+        }),
+      getUserBinding: (id) => get().userBindings[id],
+    }),
+    {
+      name: 'mc-command-store',
+      // Only persist user-customizable bindings; handlers are runtime-only.
+      partialize: (state) => ({ userBindings: state.userBindings }),
+    }
+  )
+);

src/renderer/stores/editor-store.ts

@@ -0,0 +1,63 @@
+import { create } from 'zustand';
+import { immer } from 'zustand/middleware/immer';
+import { enableMapSet } from 'immer';
+
+enableMapSet();
+
+export interface Buffer {
+  id: string;
+  path: string;
+  content: string;
+  dirty: boolean;
+  cursor?: { line: number; column: number };
+}
+
+interface EditorState {
+  buffers: Map<string, Buffer>;
+  activeId: string | null;
+  openBuffer: (id: string, path: string, content: string) => void;
+  updateContent: (id: string, content: string) => void;
+  markSaved: (id: string) => void;
+  setCursor: (id: string, line: number, column: number) => void;
+  closeBuffer: (id: string) => void;
+  setActive: (id: string) => void;
+}
+
+export const useEditorStore = create<EditorState>()(
+  immer((set) => ({
+    buffers: new Map(),
+    activeId: null,
+    openBuffer: (id, path, content) =>
+      set((s) => {
+        s.buffers.set(id, { id, path, content, dirty: false });
+        s.activeId = id;
+      }),
+    updateContent: (id, content) =>
+      set((s) => {
+        const buf = s.buffers.get(id);
+        if (buf) {
+          buf.content = content;
+          buf.dirty = true;
+        }
+      }),
+    markSaved: (id) =>
+      set((s) => {
+        const buf = s.buffers.get(id);
+        if (buf) buf.dirty = false;
+      }),
+    setCursor: (id, line, column) =>
+      set((s) => {
+        const buf = s.buffers.get(id);
+        if (buf) buf.cursor = { line, column };
+      }),
+    closeBuffer: (id) =>
+      set((s) => {
+        s.buffers.delete(id);
+        if (s.activeId === id) s.activeId = null;
+      }),
+    setActive: (id) =>
+      set((s) => {
+        s.activeId = id;
+      }),
+  }))
+);

src/renderer/stores/file-store.ts

@@ -0,0 +1,247 @@
+import { create } from 'zustand';
+import { persist, createJSONStorage } from 'zustand/middleware';
+import { immer } from 'zustand/middleware/immer';
+import { enableMapSet } from 'immer';
+import { ipc } from '@/lib/ipc';
+import { toast } from '@/lib/toast';
+import { useEditorStore } from '@/stores/editor-store';
+import type { FileEntry } from '@/types/ipc';
+
+enableMapSet();
+
+export interface FileNode {
+  name: string;
+  path: string;
+  isDirectory: boolean;
+  children: FileNode[] | null;
+  expanded?: boolean;
+  loaded?: boolean;
+}
+
+export interface OpenTab {
+  id: string;
+  path: string;
+  title: string;
+  dirty: boolean;
+}
+
+interface FileState {
+  tree: FileNode | null;
+  rootPath: string | null;
+  expanded: Set<string>;
+  openTabs: OpenTab[];
+  activeTabId: string | null;
+
+  openFolder: (path: string) => Promise<void>;
+  loadChildren: (dirPath: string) => Promise<void>;
+  toggleExpanded: (dirPath: string) => void;
+  openFile: (filePath: string) => Promise<void>;
+  closeTab: (id: string) => void;
+  setActiveTab: (id: string) => void;
+  markTabClean: (id: string) => void;
+  markTabDirty: (id: string) => void;
+  reorderTabs: (fromIndex: number, toIndex: number) => void;
+  openFolderDialog: () => Promise<void>;
+  openFileDialog: () => Promise<void>;
+  saveActiveBuffer: () => Promise<boolean>;
+}
+
+function entryToNode(entry: FileEntry): FileNode {
+  return {
+    name: entry.name,
+    path: entry.path,
+    isDirectory: entry.isDirectory,
+    children: null, // lazy: start unloaded; loadChildren populates this
+  };
+}
+
+// Recursively find and update a directory node by path using immer's produce
+function updateNode(tree: FileNode, dirPath: string, updater: (node: FileNode) => void): boolean {
+  if (tree.path === dirPath && tree.isDirectory) {
+    updater(tree);
+    return true;
+  }
+  if (tree.children) {
+    for (const child of tree.children) {
+      if (updateNode(child, dirPath, updater)) return true;
+    }
+  }
+  return false;
+}
+
+export const useFileStore = create<FileState>()(
+  persist(
+    immer((set) => ({
+    tree: null,
+    rootPath: null,
+    expanded: new Set<string>(),
+    openTabs: [],
+    activeTabId: null,
+
+    openFolder: async (path) => {
+      const result = await ipc.file.list(path);
+      if (!result.ok) {
+        toast.error(`Failed to open folder: ${result.error.message}`);
+        return;
+      }
+
+      const children: FileNode[] = result.data!.map(entryToNode);
+
+      set((s) => {
+        s.tree = {
+          name: path.split('/').filter(Boolean).pop() ?? path,
+          path,
+          isDirectory: true,
+          children,
+          loaded: true,
+        };
+        s.rootPath = path;
+      });
+    },
+
+    loadChildren: async (dirPath) => {
+      // Find the node first
+      const tree = useFileStore.getState().tree;
+      if (!tree) return;
+
+      let found = false;
+      updateNode(tree, dirPath, (node) => {
+        if (node.loaded === true) return;
+        found = true;
+      });
+      if (!found) return;
+
+      const result = await ipc.file.list(dirPath);
+      if (!result.ok) return;
+
+      set((s) => {
+        updateNode(s.tree!, dirPath, (node) => {
+          node.children = result.data!.map(entryToNode);
+          node.loaded = true;
+        });
+      });
+    },
+
+    toggleExpanded: (dirPath) => {
+      set((s) => {
+        if (s.expanded.has(dirPath)) {
+          s.expanded.delete(dirPath);
+        } else {
+          s.expanded.add(dirPath);
+        }
+      });
+    },
+
+    openFile: async (filePath) => {
+      // If already open, sync dirty flag from editor buffer and activate
+      const existing = useFileStore.getState().openTabs.find((t) => t.id === filePath);
+      if (existing) {
+        const buffer = useEditorStore.getState().buffers.get(filePath);
+        set((s) => {
+          s.activeTabId = filePath;
+          if (buffer) {
+            const tab = s.openTabs.find((t) => t.id === filePath);
+            if (tab) tab.dirty = buffer.dirty;
+          }
+        });
+        return;
+      }
+
+      const result = await ipc.file.read(filePath);
+      if (!result.ok) {
+        toast.error(`Failed to open file: ${result.error.message}`);
+        return;
+      }
+
+      const content = result.data!;
+      const title = filePath.split('/').pop() ?? filePath;
+
+      // Open in editor store
+      useEditorStore.getState().openBuffer(filePath, filePath, content);
+
+      set((s) => {
+        s.openTabs.push({ id: filePath, path: filePath, title, dirty: false });
+        s.activeTabId = filePath;
+      });
+    },
+
+    closeTab: (id) => {
+      set((s) => {
+        const idx = s.openTabs.findIndex((t) => t.id === id);
+        if (idx === -1) return;
+        s.openTabs.splice(idx, 1);
+        if (s.activeTabId === id) {
+          s.activeTabId = idx > 0 ? s.openTabs[idx - 1]?.id ?? null : null;
+        }
+      });
+    },
+
+    setActiveTab: (id) => {
+      set((s) => {
+        s.activeTabId = id;
+      });
+    },
+
+    markTabClean: (id) => {
+      set((s) => {
+        const tab = s.openTabs.find((t) => t.id === id);
+        if (tab) tab.dirty = false;
+      });
+    },
+
+    markTabDirty: (id) => {
+      set((s) => {
+        const tab = s.openTabs.find((t) => t.id === id);
+        if (tab) tab.dirty = true;
+      });
+    },
+
+    reorderTabs: (fromIndex, toIndex) => {
+      set((s) => {
+        const tabs = s.openTabs;
+        const [moved] = tabs.splice(fromIndex, 1);
+        tabs.splice(toIndex, 0, moved);
+      });
+    },
+
+    openFolderDialog: async () => {
+      const result = await ipc.file.pickFolder();
+      if (!result.ok || result.data === null) return;
+      await useFileStore.getState().openFolder(result.data);
+    },
+
+    openFileDialog: async () => {
+      const result = await ipc.file.pickFile();
+      if (!result.ok || result.data === null) return;
+      await useFileStore.getState().openFile(result.data);
+    },
+
+    saveActiveBuffer: async () => {
+      const { activeTabId } = useFileStore.getState();
+      if (!activeTabId) return false;
+
+      const buffer = useEditorStore.getState().buffers.get(activeTabId);
+      if (!buffer) return false;
+
+      const writeResult = await ipc.file.write(activeTabId, buffer.content);
+      if (!writeResult.ok) {
+        toast.error(`Failed to save: ${writeResult.error.message}`);
+        return false;
+      }
+
+      useEditorStore.getState().markSaved(activeTabId);
+      useFileStore.getState().markTabClean(activeTabId);
+      const title = useFileStore.getState().openTabs.find(t => t.id === activeTabId)?.title ?? activeTabId.split('/').pop() ?? activeTabId;
+      toast.success(`Saved ${title}`);
+      return true;
+    },
+  })),
+    {
+      name: 'mc-file-store',
+      storage: createJSONStorage(() => localStorage),
+      // Only persist the folder path; tree, expanded Set, and openTabs are
+      // rebuilt on demand. The app re-opens the folder on startup.
+      partialize: (state) => ({ rootPath: state.rootPath }),
+    }
+  )
+);

src/renderer/stores/preview-store.ts

@@ -0,0 +1,25 @@
+import { create } from 'zustand';
+
+interface PreviewState {
+  source: string;
+  scrollRatio: number;
+  setSource: (s: string) => void;
+  setScrollRatio: (r: number) => void;
+}
+
+const DEBOUNCE_MS = 300;
+let timer: ReturnType<typeof setTimeout> | null = null;
+let pending: string = '';
+
+export const usePreviewStore = create<PreviewState>((set) => ({
+  source: '',
+  scrollRatio: 0,
+  setSource: (s) => {
+    pending = s;
+    if (timer) clearTimeout(timer);
+    timer = setTimeout(() => {
+      set({ source: pending });
+    }, DEBOUNCE_MS);
+  },
+  setScrollRatio: (r) => set({ scrollRatio: r }),
+}));

src/renderer/stores/settings-store.ts

@@ -0,0 +1,38 @@
+import { create } from 'zustand';
+import { persist, createJSONStorage } from 'zustand/middleware';
+import { settingsSchema, type Settings } from '@/lib/validators';
+
+type SettingsLeaf = keyof Omit<Settings, never>;
+
+interface SettingsState extends Settings {
+  setSetting: <K extends SettingsLeaf>(key: K, value: Settings[K]) => void;
+  resetToDefaults: () => void;
+}
+
+const DEFAULTS = settingsSchema.parse({});
+
+export const useSettingsStore = create<SettingsState>()(
+  persist(
+    (set) => ({
+      ...DEFAULTS,
+      setSetting: (key, value) => set((s) => ({ ...s, [key]: value }) as Partial<SettingsState>),
+      resetToDefaults: () => set(() => ({ ...DEFAULTS })),
+    }),
+    {
+      name: 'mc-settings-store',
+      storage: createJSONStorage(() => localStorage),
+      partialize: (state) => {
+        const { setSetting, resetToDefaults, ...rest } = state;
+        return rest;
+      },
+      onRehydrateStorage: () => (state) => {
+        if (!state) return;
+        const result = settingsSchema.safeParse(state);
+        if (!result.success) {
+          console.warn('[settings-store] invalid persisted state, resetting to defaults', result.error);
+          useSettingsStore.setState({ ...DEFAULTS } as any);
+        }
+      },
+    }
+  )
+);

src/renderer/styles/globals.css

@@ -0,0 +1,98 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+@layer base {
+  :root {
+    --background: 0 0% 100%;
+    --foreground: 0 0% 9%;
+    --card: 0 0% 100%;
+    --card-foreground: 0 0% 9%;
+    --popover: 0 0% 100%;
+    --popover-foreground: 0 0% 9%;
+    --primary: 11 79% 51%;
+    --primary-foreground: 0 0% 100%;
+    --secondary: 0 0% 96%;
+    --secondary-foreground: 0 0% 9%;
+    --muted: 0 0% 96%;
+    --muted-foreground: 0 0% 45%;
+    --accent: 0 0% 96%;
+    --accent-foreground: 0 0% 9%;
+    --destructive: 0 84% 60%;
+    --destructive-foreground: 0 0% 100%;
+    --border: 0 0% 90%;
+    --input: 0 0% 90%;
+    --ring: 11 79% 51%;
+    --radius: 0.5rem;
+    --shadow-sm: 0 1px 2px rgba(13, 11, 9, 0.06);
+    --shadow-md: 0 4px 12px rgba(13, 11, 9, 0.08), 0 0 0 1px rgba(13, 11, 9, 0.04);
+    --shadow-lg: 0 12px 32px rgba(13, 11, 9, 0.12), 0 0 0 1px rgba(13, 11, 9, 0.06);
+    --shadow-glow-brand: 0 0 24px rgba(229, 70, 31, 0.25);
+    --glass-bg-light: rgba(255, 255, 255, 0.72);
+    --glass-bg-dark: rgba(13, 11, 9, 0.72);
+    --glass-border-light: rgba(255, 255, 255, 0.4);
+    --glass-border-dark: rgba(255, 255, 255, 0.08);
+  }
+
+  .dark {
+    --background: 30 14% 4%;
+    --foreground: 0 0% 98%;
+    --card: 30 14% 6%;
+    --card-foreground: 0 0% 98%;
+    --popover: 30 14% 6%;
+    --popover-foreground: 0 0% 98%;
+    --primary: 11 79% 51%;
+    --primary-foreground: 0 0% 100%;
+    --secondary: 30 6% 15%;
+    --secondary-foreground: 0 0% 98%;
+    --muted: 30 6% 15%;
+    --muted-foreground: 0 0% 63%;
+    --accent: 30 6% 15%;
+    --accent-foreground: 0 0% 98%;
+    --destructive: 0 62% 30%;
+    --destructive-foreground: 0 0% 100%;
+    --border: 30 6% 15%;
+    --input: 30 6% 15%;
+    --ring: 11 79% 51%;
+    --shadow-sm: 0 1px 2px rgba(13, 11, 9, 0.06);
+    --shadow-md: 0 4px 12px rgba(13, 11, 9, 0.08), 0 0 0 1px rgba(13, 11, 9, 0.04);
+    --shadow-lg: 0 12px 32px rgba(13, 11, 9, 0.12), 0 0 0 1px rgba(13, 11, 9, 0.06);
+    --shadow-glow-brand: 0 0 24px rgba(229, 70, 31, 0.25);
+    --glass-bg-light: rgba(255, 255, 255, 0.72);
+    --glass-bg-dark: rgba(13, 11, 9, 0.72);
+    --glass-border-light: rgba(255, 255, 255, 0.4);
+    --glass-border-dark: rgba(255, 255, 255, 0.08);
+  }
+
+  * {
+    @apply border-border;
+  }
+
+  body {
+    @apply bg-background text-foreground;
+  }
+}
+
+/* Custom scrollbar */
+::-webkit-scrollbar {
+  width: 6px;
+  height: 6px;
+}
+::-webkit-scrollbar-track {
+  background: transparent;
+}
+::-webkit-scrollbar-thumb {
+  background: hsl(var(--muted-foreground) / 0.3);
+  border-radius: 3px;
+}
+::-webkit-scrollbar-thumb:hover {
+  background: hsl(var(--muted-foreground) / 0.5);
+}
+
+/* CodeMirror integration */
+.cm-editor {
+  @apply h-full;
+}
+.cm-editor .cm-scroller {
+  @apply font-mono text-sm;
+}

src/renderer/test/setup.ts

@@ -0,0 +1,57 @@
+import '@testing-library/jest-dom/vitest';
+
+// Mock window.electronAPI for tests
+declare global {
+  interface Window {
+    electronAPI: any;
+  }
+}
+
+if (typeof window !== 'undefined' && !window.electronAPI) {
+  window.electronAPI = {};
+}
+
+// Mock matchMedia for next-themes (jsdom doesn't have it)
+if (typeof window !== 'undefined') {
+  Object.defineProperty(window, 'matchMedia', {
+    writable: true,
+    value: (query: string) => ({
+      matches: false,
+      media: query,
+      onchange: null,
+      addListener: () => {},
+      removeListener: () => {},
+      addEventListener: () => {},
+      removeEventListener: () => {},
+      dispatchEvent: () => true,
+    }),
+  });
+}
+
+// Mock react-resizable-panels for jsdom environment
+if (typeof window !== 'undefined') {
+  Object.defineProperty(window, 'innerWidth', { writable: true, value: 1920 });
+  Object.defineProperty(window, 'innerHeight', { writable: true, value: 1080 });
+}
+
+// Polyfill ResizeObserver for @radix-ui/react-use-size
+if (typeof window !== 'undefined' && !window.ResizeObserver) {
+  class ResizeObserver {
+    observe() {}
+    unobserve() {}
+    disconnect() {}
+  }
+  window.ResizeObserver = ResizeObserver;
+}
+
+// Polyfill hasPointerCapture for @radix-ui/react-select (jsdom doesn't implement it)
+if (typeof window !== 'undefined' && !Element.prototype.hasPointerCapture) {
+  Element.prototype.hasPointerCapture = function () {
+    return false;
+  };
+}
+
+// Polyfill scrollIntoView for @radix-ui/react-select (jsdom doesn't implement it)
+if (typeof window !== 'undefined' && !Element.prototype.scrollIntoView) {
+  Element.prototype.scrollIntoView = function () {};
+}

src/renderer/types/electron.d.ts

@@ -0,0 +1,90 @@
+export interface ElectronAPI {
+  // App info
+  getAppVersion: () => Promise<string>;
+
+  // File operations
+  openFile: () => Promise<{ canceled: boolean; filePaths: string[] }>;
+  saveFile: (data: { path: string; content: string }) => Promise<void>;
+  readFile: (path: string) => Promise<string>;
+  setCurrentFile: (path: string | null) => void;
+
+  // Export
+  exportDocument: (format: string, options?: Record<string, any>) => Promise<void>;
+
+  // Theme
+  getTheme: () => void;
+  onThemeChanged: (callback: (theme: string) => void) => () => void;
+
+  // File events
+  onFileOpened: (callback: (data: { path: string; content: string }) => void) => () => void;
+  onFileNew: (callback: () => void) => () => void;
+  onFileSave: (callback: () => void) => () => void;
+
+  // Conversion status
+  onConversionStatus: (callback: (message: string) => void) => () => void;
+  onConversionComplete: (callback: (data: { format: string; outputPath: string }) => void) => () => void;
+
+  // Dialogs
+  showExportDialog: (format: string) => void;
+  showBatchDialog: () => void;
+  showUniversalConverterDialog: () => void;
+  showTableGenerator: () => void;
+  showPdfEditorDialog: () => void;
+  showHeaderFooterDialog: () => void;
+  showFieldPickerDialog: () => void;
+
+  // Settings
+  getSettings: (key: string) => Promise<any>;
+  setSettings: (key: string, value: any) => Promise<void>;
+
+  // Plugin settings
+  getPluginSetting: (key: string) => Promise<any>;
+  setPluginSetting: (key: string, value: any) => Promise<void>;
+
+  // Sidebar
+  toggleSidebar: () => void;
+  toggleBottomPanel: () => void;
+
+  // Print
+  doPrint: (options?: any) => void;
+
+  // PDF
+  openPdfViewer: (filePath: string) => void;
+  processPdfOperation: (data: any) => void;
+
+  // Images
+  selectFolder: () => Promise<string | null>;
+  savePastedImage: (data: { base64: string; ext: string }) => Promise<{ relativePath: string } | null>;
+
+  // Templates
+  loadTemplate: (file: string) => Promise<string>;
+  getSnippets: () => Promise<any[]>;
+  saveSnippet: (snippet: any) => Promise<void>;
+  deleteSnippet: (id: string) => Promise<void>;
+
+  // Git
+  gitStatus: () => Promise<any>;
+  gitDiff: (file: string) => Promise<any>;
+  gitStage: (files: string[]) => Promise<void>;
+  gitCommit: (message: string) => Promise<void>;
+  gitLog: () => Promise<any[]>;
+
+  // Directory
+  listDirectory: (dir: string) => Promise<any[] | null>;
+  openFilePath: (path: string) => void;
+
+  // Custom CSS
+  selectCustomCSS: () => Promise<string | null>;
+  loadCustomCSS: () => void;
+  clearCustomCSS: () => void;
+
+  // Generic invoke/on
+  invoke: (channel: string, data?: any) => Promise<any>;
+  on: (channel: string, callback: (...args: any[]) => void) => () => void;
+}
+
+declare global {
+  interface Window {
+    electronAPI: ElectronAPI;
+  }
+}

src/renderer/types/ipc.ts

@@ -0,0 +1,62 @@
+export type IpcResult<T> =
+  | { ok: true; data: T }
+  | { ok: false; error: { code: string; message: string } };
+
+export interface FileEntry {
+  name: string;
+  path: string;
+  isDirectory: boolean;
+  size?: number;
+  modifiedAt?: string;
+}
+
+export interface FileResult {
+  path: string;
+  content: string;
+}
+
+export interface PdfOptions {
+  inputPath: string;
+  outputPath: string;
+  format?: 'letter' | 'a4' | 'legal';
+  margins?: { top: number; right: number; bottom: number; left: number };
+  toc?: boolean;
+  embedFonts?: boolean;
+}
+
+export interface DocxOptions {
+  inputPath: string;
+  outputPath: string;
+  template?: string;
+  referenceDoc?: string;
+}
+
+export interface HtmlOptions {
+  inputPath: string;
+  outputPath: string;
+  standalone?: boolean;
+  highlightStyle?: string;
+}
+
+export interface ExportResult {
+  outputPath: string;
+  bytes: number;
+  durationMs: number;
+}
+
+export interface BatchItem {
+  inputPath: string;
+  outputPath: string;
+}
+
+export interface BatchOptions {
+  format: 'pdf' | 'docx' | 'html' | 'png';
+  concurrency?: number;
+}
+
+export interface BatchResult {
+  total: number;
+  succeeded: number;
+  failed: number;
+  results: Array<{ item: BatchItem; ok: boolean; error?: string }>;
+}

src/styles-modern.css

@@ -2372,3 +2372,254 @@ body[class*="dark"] .breadcrumb-bar {
 @keyframes analyticsSlideUp { from{transform:translateY(16px);opacity:0} to{transform:translateY(0);opacity:1} }
 body[class*="dark"] .analytics-modal { background:var(--gray-800,#1f2937); }
 body[class*="dark"] .word-tag { background:var(--gray-700,#374151); }
+
+/* ========================================
+   Interactive PDF Thumbnail Sidebar Styles
+   ======================================== */
+.pdf-editor-body.side-by-side {
+  display: flex;
+  flex-direction: row;
+  gap: 16px;
+  height: 550px;
+  overflow: hidden;
+}
+
+.pdf-editor-left-panel {
+  flex: 1.2;
+  overflow-y: auto;
+  padding-right: 8px;
+  height: 100%;
+}
+
+.pdf-editor-right-panel {
+  flex: 0.8;
+  display: flex;
+  flex-direction: column;
+  border-left: 1px solid var(--border-color, #e5e7eb);
+  padding-left: 16px;
+  height: 100%;
+  overflow: hidden;
+}
+
+.pdf-editor-right-panel h4 {
+  margin: 0 0 4px 0;
+  font-size: 15px;
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
+.pdf-editor-right-panel .sidebar-help {
+  margin: 0 0 12px 0;
+  font-size: 11px;
+  color: var(--text-secondary, #6b7280);
+  line-height: 1.4;
+}
+
+.pdf-thumbnail-grid {
+  flex: 1;
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
+  gap: 12px;
+  overflow-y: auto;
+  padding: 4px;
+}
+
+.pdf-thumbnail-card {
+  display: flex;
+  flex-direction: column;
+  border: 1px solid var(--border-color, #e5e7eb);
+  border-radius: 8px;
+  background: var(--bg-primary, #ffffff);
+  box-shadow: var(--shadow-sm);
+  padding: 8px;
+  transition: all var(--transition-speed, 0.3s) var(--transition-ease);
+  position: relative;
+  overflow: hidden;
+}
+
+.pdf-thumbnail-card:hover {
+  transform: translateY(-2px);
+  box-shadow: var(--shadow-md);
+  border-color: var(--primary-light, #8b9aff);
+}
+
+.pdf-thumbnail-card.marked-delete {
+  border-color: var(--error, #ef4444);
+  background: rgba(239, 68, 68, 0.05);
+}
+
+.pdf-thumbnail-card.marked-delete::after {
+  content: "DELETE";
+  position: absolute;
+  top: 50%;
+  left: 50%;
+  transform: translate(-50%, -50%) rotate(-15deg);
+  background: rgba(239, 68, 68, 0.95);
+  color: #fff;
+  font-size: 10px;
+  font-weight: 700;
+  padding: 4px 8px;
+  border-radius: 4px;
+  pointer-events: none;
+  box-shadow: var(--shadow-sm);
+  letter-spacing: 0.5px;
+  white-space: nowrap;
+}
+
+.pdf-thumbnail-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 6px;
+}
+
+.pdf-thumbnail-header .badge {
+  font-size: 11px;
+  font-weight: 600;
+  background: var(--bg-tertiary, #f3f4f6);
+  color: var(--text-primary);
+  padding: 2px 6px;
+  border-radius: 4px;
+  font-family: var(--font-mono, monospace);
+}
+
+.canvas-container {
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  background: var(--bg-secondary, #f9fafb);
+  border: 1px solid var(--border-color, #e5e7eb);
+  border-radius: 6px;
+  padding: 6px;
+  height: 120px;
+  overflow: hidden;
+}
+
+.pdf-thumbnail-canvas {
+  max-width: 100%;
+  max-height: 100%;
+  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08);
+  transition: transform 0.3s ease;
+}
+
+/* CSS Rotations */
+.rot90 {
+  transform: rotate(90deg);
+}
+.rot180 {
+  transform: rotate(180deg);
+}
+.rot270 {
+  transform: rotate(270deg);
+}
+
+.pdf-thumbnail-controls {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  margin-top: 8px;
+}
+
+.pdf-thumbnail-controls button,
+.pdf-thumbnail-controls label {
+  font-size: 11px;
+}
+
+.btn-rotate-thumbnail {
+  background: var(--bg-tertiary, #f3f4f6);
+  border: 1px solid var(--border-color, #e5e7eb);
+  color: var(--text-primary);
+  border-radius: 4px;
+  padding: 3px 6px;
+  cursor: pointer;
+  width: 100%;
+  text-align: center;
+  transition: all 0.2s;
+  font-weight: 500;
+}
+
+.btn-rotate-thumbnail:hover {
+  background: var(--primary-light, #8b9aff);
+  color: #fff;
+  border-color: var(--primary-dark);
+}
+
+.delete-thumbnail-checkbox {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 4px;
+  cursor: pointer;
+  user-select: none;
+  font-weight: 500;
+  color: var(--text-secondary);
+}
+
+.delete-thumbnail-checkbox input {
+  margin: 0;
+  cursor: pointer;
+}
+
+.pdf-thumbnail-reorder {
+  display: flex;
+  justify-content: space-between;
+  gap: 4px;
+}
+
+.btn-reorder-left,
+.btn-reorder-right {
+  flex: 1;
+  background: var(--bg-tertiary, #f3f4f6);
+  border: 1px solid var(--border-color, #e5e7eb);
+  color: var(--text-primary);
+  border-radius: 4px;
+  padding: 2px;
+  cursor: pointer;
+  transition: all 0.2s;
+}
+
+.btn-reorder-left:hover:not(:disabled),
+.btn-reorder-right:hover:not(:disabled) {
+  background: var(--bg-secondary);
+  border-color: var(--text-muted);
+}
+
+.btn-reorder-left:disabled,
+.btn-reorder-right:disabled {
+  opacity: 0.3;
+  cursor: not-allowed;
+}
+
+.loading-thumbnails,
+.thumbnail-error {
+  grid-column: 1 / -1;
+  text-align: center;
+  padding: 40px 20px;
+  font-size: 13px;
+  color: var(--text-muted);
+}
+
+.thumbnail-error {
+  color: var(--error, #ef4444);
+}
+
+/* Dark mode adjustments */
+body[class*="dark"] .pdf-thumbnail-card {
+  background: var(--gray-800, #1f2937);
+  border-color: var(--gray-700, #374151);
+}
+body[class*="dark"] .pdf-thumbnail-header .badge {
+  background: var(--gray-700, #374151);
+  color: var(--gray-200);
+}
+body[class*="dark"] .canvas-container {
+  background: var(--gray-900, #111827);
+  border-color: var(--gray-700);
+}
+body[class*="dark"] .btn-rotate-thumbnail,
+body[class*="dark"] .btn-reorder-left,
+body[class*="dark"] .btn-reorder-right {
+  background: var(--gray-700, #374151);
+  border-color: var(--gray-600);
+  color: var(--gray-200);
+}

src/utils/ModalManager.js

@@ -1,6 +1,6 @@
 /**
  * ModalManager - Unified modal system with accessibility support
- * @version 4.4.1
+ * @version 4.4.2
  */
 class ModalManager {
     #modal;

src/wordTemplateExporter.js

@@ -655,7 +655,7 @@ class WordTemplateExporter {
      */
     parseInlineFormatting(text) {
         let xml = '';
-        let pos = 0;
+        const pos = 0;
 
         // Patterns for inline formatting
         const patterns = [

src/zen-mode.js

@@ -117,7 +117,7 @@ class ZenMode {
     _applyTypewriterBehavior(view) {
         // We use a custom update listener that scrolls the cursor to center.
         // This is stored on the instance so we can clean it up.
-        let scrollTimeout = null;
+        const scrollTimeout = null;
 
         const scrollFn = () => {
             if (!this.active) return;

tailwind.config.js

@@ -0,0 +1,87 @@
+const animate = require('tailwindcss-animate')
+
+/** @type {import('tailwindcss').Config} */
+module.exports = {
+  darkMode: ['class'],
+  content: [
+    './src/renderer/**/*.{js,ts,jsx,tsx}',
+    './src/renderer/index.html',
+  ],
+  theme: {
+    container: {
+      center: true,
+      padding: '2rem',
+      screens: { '2xl': '1400px' },
+    },
+    extend: {
+      colors: {
+        border: 'hsl(var(--border))',
+        input: 'hsl(var(--input))',
+        ring: 'hsl(var(--ring))',
+        background: 'hsl(var(--background))',
+        foreground: 'hsl(var(--foreground))',
+        primary: {
+          DEFAULT: 'hsl(var(--primary))',
+          foreground: 'hsl(var(--primary-foreground))',
+        },
+        secondary: {
+          DEFAULT: 'hsl(var(--secondary))',
+          foreground: 'hsl(var(--secondary-foreground))',
+        },
+        destructive: {
+          DEFAULT: 'hsl(var(--destructive))',
+          foreground: 'hsl(var(--destructive-foreground))',
+        },
+        muted: {
+          DEFAULT: 'hsl(var(--muted))',
+          foreground: 'hsl(var(--muted-foreground))',
+        },
+        accent: {
+          DEFAULT: 'hsl(var(--accent))',
+          foreground: 'hsl(var(--accent-foreground))',
+        },
+        popover: {
+          DEFAULT: 'hsl(var(--popover))',
+          foreground: 'hsl(var(--popover-foreground))',
+        },
+        card: {
+          DEFAULT: 'hsl(var(--card))',
+          foreground: 'hsl(var(--card-foreground))',
+        },
+        brand: {
+          DEFAULT: '#e5461f',
+          dark: '#c93a18',
+          light: '#ff6b47',
+        },
+        success: '#1a7a56',
+        warning: 'hsl(45 93% 47%)',
+        danger: 'hsl(0 84% 60%)',
+        info: 'hsl(199 89% 48%)',
+        warm: {
+          50: '#fafbfc', 100: '#f5f5f5', 200: '#e3e3e3', 300: '#d1d1d1',
+          400: '#b0b0b0', 500: '#9a9696', 600: '#7a7878', 700: '#5a5858',
+          800: '#4e4e4e', 900: '#464646', 950: '#0d0b09',
+        },
+      },
+      borderRadius: {
+        lg: 'var(--radius)',
+        md: 'calc(var(--radius) - 2px)',
+        sm: 'calc(var(--radius) - 4px)',
+      },
+      fontFamily: {
+        sans: ['"Plus Jakarta Sans"', 'system-ui', 'sans-serif'],
+        display: ['"Barlow Condensed"', 'system-ui', 'sans-serif'],
+        mono: ['"JetBrains Mono"', '"Fira Code"', '"SF Mono"', 'Consolas', 'monospace'],
+      },
+      keyframes: {
+        'accordion-down': { from: { height: '0' }, to: { height: 'var(--radix-accordion-content-height)' } },
+        'accordion-up': { from: { height: 'var(--radix-accordion-content-height)' }, to: { height: '0' } },
+      },
+      animation: {
+        'accordion-down': 'accordion-down 0.2s ease-out',
+        'accordion-up': 'accordion-up 0.2s ease-out',
+      },
+    },
+  },
+  plugins: [animate],
+}

tests/component/editor/EditorPane.test.tsx

@@ -0,0 +1,38 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { ThemeProvider } from '@/components/theme-provider';
+import { EditorPane } from '@/components/editor/EditorPane';
+import { useEditorStore } from '@/stores/editor-store';
+import { CodeMirrorEditor } from '@/components/editor/CodeMirrorEditor';
+
+vi.mock('@/components/editor/CodeMirrorEditor', () => ({
+  CodeMirrorEditor: ({ initialContent }: { initialContent: string }) => (
+    <div data-testid="codemirror-mock">{initialContent}</div>
+  ),
+}));
+
+describe('EditorPane', () => {
+  beforeEach(() => {
+    useEditorStore.setState({ buffers: new Map(), activeId: null });
+  });
+
+  it('renders the empty state when no buffer is open', () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <EditorPane />
+      </ThemeProvider>
+    );
+    expect(screen.getByText(/no file open/i)).toBeInTheDocument();
+  });
+
+  it('renders the editor when a buffer is open', () => {
+    useEditorStore.getState().openBuffer('b1', '/x.md', '# hello');
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <EditorPane />
+      </ThemeProvider>
+    );
+    expect(screen.getByTestId('codemirror-mock')).toBeInTheDocument();
+    expect(screen.getByTestId('codemirror-mock')).toHaveTextContent('# hello');
+  });
+});

tests/component/layout/AppHeader.test.tsx

@@ -0,0 +1,93 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { ThemeProvider } from '@/components/theme-provider';
+import { AppHeader } from '@/components/layout/AppHeader';
+import { useAppStore } from '@/stores/app-store';
+import { useCommandStore } from '@/stores/command-store';
+
+describe('AppHeader', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    useAppStore.setState({ sidebarVisible: true, previewVisible: true, zenMode: false });
+    useCommandStore.setState({ handlers: {} });
+    // Mirror what AppShell registers so dispatching actually does something.
+    useCommandStore.getState().register('view.toggleSidebar', () => {
+      useAppStore.getState().toggleSidebar();
+    });
+    useCommandStore.getState().register('view.togglePreview', () => {
+      useAppStore.getState().togglePreview();
+    });
+    useCommandStore.getState().register('shortcuts.show', () => {});
+    useCommandStore.getState().register('settings.open', () => {
+      useAppStore.getState().openModal('settings');
+    });
+    useCommandStore.getState().register('help.about', () => {
+      useAppStore.getState().openModal('about');
+    });
+  });
+
+  it('renders the app title', () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <AppHeader />
+      </ThemeProvider>
+    );
+    expect(screen.getByText(/markdownconverter/i)).toBeInTheDocument();
+  });
+
+  it('toggles sidebar when sidebar button clicked', async () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <AppHeader />
+      </ThemeProvider>
+    );
+    const btn = screen.getByRole('button', { name: /toggle sidebar/i });
+    await userEvent.click(btn);
+    expect(useAppStore.getState().sidebarVisible).toBe(false);
+  });
+
+  it('toggles preview when preview button clicked', async () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <AppHeader />
+      </ThemeProvider>
+    );
+    const btn = screen.getByRole('button', { name: /toggle preview/i });
+    await userEvent.click(btn);
+    expect(useAppStore.getState().previewVisible).toBe(false);
+  });
+
+  it('disables-shortcut button dispatches shortcuts.show', async () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <AppHeader />
+      </ThemeProvider>
+    );
+    const btn = screen.getByTestId('header-shortcuts');
+    await userEvent.click(btn);
+    // No observable side effect; the command was registered as a no-op.
+    // The test passes if no error is thrown and the click is processed.
+    expect(btn).toBeInTheDocument();
+  });
+
+  it('settings button opens settings modal', async () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <AppHeader />
+      </ThemeProvider>
+    );
+    await userEvent.click(screen.getByRole('button', { name: /settings/i }));
+    expect(useAppStore.getState().modal).toEqual({ kind: 'settings' });
+  });
+
+  it('about button opens about modal', async () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <AppHeader />
+      </ThemeProvider>
+    );
+    await userEvent.click(screen.getByRole('button', { name: /^about$/i }));
+    expect(useAppStore.getState().modal).toEqual({ kind: 'about' });
+  });
+});