test(renderer): Phase 7 modals integration smoke test

- 7 end-to-end tests covering toolbar, header, native menu IPC,
  userBindings persistence, and command registry
- 169/169 tests pass (was 105 at end of Phase 5)
- build succeeds

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-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

@@ -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",
@@ -70,6 +94,23 @@
     "@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",
@@ -79,16 +120,26 @@
     "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",

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 -->

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);
 }
@@ -3037,6 +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}`),

src/preload.js

@@ -237,7 +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'
 ];
 
 /**
@@ -344,7 +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

@@ -4,6 +4,17 @@
  */
 
 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');
@@ -11,13 +22,10 @@ const DOMPurify = createDOMPurify(window);
 const hljs = require('highlight.js');
 const { createEditor } = require('./editor/codemirror-setup');
 const { undo, redo } = require('@codemirror/commands');
-// Use window.ModalManager if already set by script tag, otherwise require it.
-// This prevents "Identifier 'ModalManager' has already been declared" when
-// both the script tag in index.html and CommonJS require() declare it.
-let ModalManager;
-if (typeof window !== 'undefined' && window.ModalManager) {
-    ModalManager = window.ModalManager;
-} else {
+// 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;
 }
@@ -482,38 +490,7 @@ class TabManager {
         document.querySelector('.editor-container').appendChild(tabContent);
 
         // Initialize CodeMirror editor
-        const editorContainer = document.getElementById(`editor-cm-${tab.id}`);
-        if (editorContainer) {
-            const isDark = document.body.className.includes('dark');
-            tab.editorView = createEditor(editorContainer, {
-                content: tab.content,
-                onChange: (newContent) => {
-                    tab.content = newContent;
-                    tab.isDirty = true;
-                    // Dynamically enable/disable Large File Mode on edit
-                    if (newContent.length > 1024 * 1024) {
-                        if (!tab.largeFileMode) {
-                            tab.largeFileMode = true;
-                            this.isPreviewVisible = false;
-                            this.updatePreviewVisibility();
-                            notifyUser('Large content detected (>1MB). Large File Mode enabled to maintain peak responsiveness. Live preview auto-render is disabled.', 'warning');
-                        }
-                    } else {
-                        tab.largeFileMode = false;
-                    }
-                    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,
-            });
-        }
+        this.ensureEditor(tab);
     }
     
     switchToTab(tabId) {
@@ -1484,9 +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 }
@@ -1730,7 +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}`);
@@ -1899,27 +1915,9 @@ document.addEventListener('DOMContentLoaded', async () => {
     });
 
     // Initialize CodeMirror for the initial tab (tab 1)
-    const initialEditorContainer = document.getElementById('editor-cm-1');
-    if (initialEditorContainer) {
-        const tab = tabManager.tabs.get(1);
-        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,
-        });
+    const initialTab = tabManager.tabs.get(1);
+    if (initialTab) {
+        tabManager.ensureEditor(initialTab);
     }
 
     // Request current theme
@@ -2041,6 +2039,8 @@ ipcRenderer.on('redo', () => {
             redo(tab.editorView);
         }
     }
+});
+
 // Custom Preview CSS event handlers and trigger helpers
 function applyCustomPreviewCSS(cssContent) {
     let styleTag = document.getElementById('custom-preview-style');

src/renderer/App.tsx

@@ -0,0 +1,14 @@
+import { AppShell } from './components/layout/AppShell';
+import { ModalLayer } from './components/modals/ModalLayer';
+import { useWelcomeTrigger } from './hooks/use-welcome-trigger';
+
+function App() {
+  useWelcomeTrigger();
+  return (
+    <>
+      <AppShell />
+      <ModalLayer />
+    </>
+  );
+}
+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 +1,79 @@
+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 { 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) {
+      setError(result.error.message);
+      setSubmitting(false);
+    } else {
+      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 +1,75 @@
+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 { 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) {
+      setError(result.error.message);
+      setSubmitting(false);
+    } else {
+      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 +1,79 @@
+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 { 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) {
+      setError(result.error.message);
+      setSubmitting(false);
+    } else {
+      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 +1,102 @@
+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 { 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.data?.ok) {
+      setError(result.data?.error?.message ?? 'Export failed');
+      setSubmitting(false);
+    } else {
+      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/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 +1,38 @@
+/**
+ * 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))
+  );
+  const lines = rows.map((row) =>
+    '| ' +
+    Array.from({ length: numCols }, (_, c) => (row[c] ?? '').padEnd(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/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 +1,235 @@
+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 { 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) 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) 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) return false;
+
+      useEditorStore.getState().markSaved(activeTabId);
+      useFileStore.getState().markTabClean(activeTabId);
+      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 }>;
+}

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' });
+  });
+});

tests/component/layout/AppShell.test.tsx

@@ -0,0 +1,49 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { ThemeProvider } from '@/components/theme-provider';
+import { AppShell } from '@/components/layout/AppShell';
+import { useAppStore } from '@/stores/app-store';
+
+// Mock react-resizable-panels for jsdom environment
+vi.mock('@/components/ui/resizable', () => ({
+  ResizablePanelGroup: ({ children, direction, onLayout }: any) => (
+    <div data-testid="resizable-panel-group" data-direction={direction}>
+      {children}
+    </div>
+  ),
+  ResizablePanel: ({ children, defaultSize, minSize, maxSize }: any) => (
+    <div data-testid="resizable-panel" data-size={defaultSize} data-min={minSize} data-max={maxSize}>
+      {children}
+    </div>
+  ),
+  ResizableHandle: () => <div data-testid="resizable-handle" />,
+}));
+
+describe('AppShell', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    useAppStore.setState({ sidebarVisible: true, previewVisible: true, zenMode: false });
+  });
+
+  it('renders all shell surfaces when sidebar and preview are visible', () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <AppShell />
+      </ThemeProvider>
+    );
+    expect(screen.getByText(/markdownconverter/i)).toBeInTheDocument();
+    expect(screen.getByText(/no files open/i)).toBeInTheDocument();
+    expect(screen.getByText(/no file selected/i)).toBeInTheDocument();
+    expect(screen.getByText(/0 words/i)).toBeInTheDocument();
+  });
+
+  it('hides sidebar when sidebarVisible is false', () => {
+    useAppStore.setState({ sidebarVisible: false });
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <AppShell />
+      </ThemeProvider>
+    );
+    expect(screen.queryByText(/file tree placeholder/i)).not.toBeInTheDocument();
+  });
+});

tests/component/layout/StatusBar.test.tsx

@@ -0,0 +1,10 @@
+import { describe, it, expect } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { StatusBar } from '@/components/layout/StatusBar';
+
+describe('StatusBar', () => {
+  it('renders zero word count when no file is open', () => {
+    render(<StatusBar />);
+    expect(screen.getByText(/0 words/i)).toBeInTheDocument();
+  });
+});

tests/component/layout/TabBar.test.tsx

@@ -0,0 +1,116 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { render, screen, act } from '@testing-library/react';
+import { TabBar } from '@/components/layout/TabBar';
+import { useFileStore } from '@/stores/file-store';
+
+describe('TabBar', () => {
+  beforeEach(() => {
+    useFileStore.setState({ openTabs: [], activeTabId: null });
+  });
+
+  it('renders "No files open" when openTabs is empty', () => {
+    render(<TabBar />);
+    expect(screen.getByText(/no files open/i)).toBeInTheDocument();
+  });
+
+  it('renders a tab for each OpenTab', () => {
+    useFileStore.setState({
+      openTabs: [
+        { id: '/tmp/foo.md', path: '/tmp/foo.md', title: 'foo.md', dirty: false },
+        { id: '/tmp/bar.md', path: '/tmp/bar.md', title: 'bar.md', dirty: false },
+      ],
+      activeTabId: '/tmp/foo.md',
+    });
+    render(<TabBar />);
+    expect(screen.getByText('foo.md')).toBeInTheDocument();
+    expect(screen.getByText('bar.md')).toBeInTheDocument();
+  });
+
+  it('highlights the active tab with aria-current', () => {
+    useFileStore.setState({
+      openTabs: [
+        { id: '/tmp/foo.md', path: '/tmp/foo.md', title: 'foo.md', dirty: false },
+        { id: '/tmp/bar.md', path: '/tmp/bar.md', title: 'bar.md', dirty: false },
+      ],
+      activeTabId: '/tmp/foo.md',
+    });
+    render(<TabBar />);
+    const fooTab = screen.getByText('foo.md').closest('[role="tab"]');
+    expect(fooTab).toHaveAttribute('aria-current', 'page');
+    const barTab = screen.getByText('bar.md').closest('[role="tab"]');
+    expect(barTab).not.toHaveAttribute('aria-current');
+  });
+
+  it('clicking a tab calls setActiveTab', async () => {
+    useFileStore.setState({
+      openTabs: [
+        { id: '/tmp/foo.md', path: '/tmp/foo.md', title: 'foo.md', dirty: false },
+        { id: '/tmp/bar.md', path: '/tmp/bar.md', title: 'bar.md', dirty: false },
+      ],
+      activeTabId: '/tmp/foo.md',
+    });
+    render(<TabBar />);
+    await act(async () => {
+      screen.getByText('bar.md').closest('[role="tab"]')!.click();
+    });
+    expect(useFileStore.getState().activeTabId).toBe('/tmp/bar.md');
+  });
+
+  it('clicking the close button calls closeTab and does not call setActiveTab separately', async () => {
+    // Use a non-active tab to test that closeTab doesn't change activeTabId
+    useFileStore.setState({
+      openTabs: [
+        { id: '/tmp/foo.md', path: '/tmp/foo.md', title: 'foo.md', dirty: false },
+        { id: '/tmp/bar.md', path: '/tmp/bar.md', title: 'bar.md', dirty: false },
+      ],
+      activeTabId: '/tmp/bar.md',
+    });
+    render(<TabBar />);
+
+    const fooTab = screen.getByText('foo.md');
+    const closeBtn = fooTab.closest('[role="tab"]')!.querySelector('button')!;
+    await act(async () => {
+      closeBtn.click();
+    });
+
+    const state = useFileStore.getState();
+    expect(state.openTabs.find((t) => t.id === '/tmp/foo.md')).toBeUndefined();
+    // activeTabId stays on bar since we closed a non-active tab
+    expect(state.activeTabId).toBe('/tmp/bar.md');
+  });
+
+  it('renders a dirty indicator when dirty === true', () => {
+    useFileStore.setState({
+      openTabs: [
+        { id: '/tmp/foo.md', path: '/tmp/foo.md', title: 'foo.md', dirty: true },
+      ],
+      activeTabId: '/tmp/foo.md',
+    });
+    render(<TabBar />);
+    const dirtyDot = screen.getByLabelText('Unsaved changes');
+    expect(dirtyDot).toBeInTheDocument();
+  });
+
+  it('reorders tabs when reorderTabs is called (drag end handler integration)', () => {
+    useFileStore.setState({
+      openTabs: [
+        { id: '/tmp/a.md', path: '/tmp/a.md', title: 'a.md', dirty: false },
+        { id: '/tmp/b.md', path: '/tmp/b.md', title: 'b.md', dirty: false },
+        { id: '/tmp/c.md', path: '/tmp/c.md', title: 'c.md', dirty: false },
+      ],
+      activeTabId: '/tmp/a.md',
+    });
+    render(<TabBar />);
+    // Initial DOM order
+    const initialOrder = screen.getAllByRole('tab').map((el) => el.getAttribute('data-testid'));
+    expect(initialOrder).toEqual(['tab-/tmp/a.md', 'tab-/tmp/b.md', 'tab-/tmp/c.md']);
+
+    // Simulate what dnd-kit's onDragEnd would do: move a.md (idx 0) to idx 2
+    act(() => {
+      useFileStore.getState().reorderTabs(0, 2);
+    });
+
+    const newOrder = screen.getAllByRole('tab').map((el) => el.getAttribute('data-testid'));
+    expect(newOrder).toEqual(['tab-/tmp/b.md', 'tab-/tmp/c.md', 'tab-/tmp/a.md']);
+  });
+});

tests/component/layout/Toolbar.test.tsx

@@ -0,0 +1,98 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { render, screen, fireEvent, act } from '@testing-library/react';
+import { Toolbar } from '@/components/layout/Toolbar';
+import { useCommandStore } from '@/stores/command-store';
+import { useAppStore } from '@/stores/app-store';
+
+describe('Toolbar', () => {
+  beforeEach(() => {
+    useCommandStore.setState({ handlers: {} });
+    useAppStore.setState({
+      sidebarVisible: true,
+      previewVisible: true,
+      zenMode: false,
+      paneSizes: { sidebar: 20, editor: 50, preview: 30 },
+    });
+  });
+
+  it('renders formatting buttons', () => {
+    render(<Toolbar />);
+    expect(screen.getByRole('button', { name: /bold/i })).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: /italic/i })).toBeInTheDocument();
+  });
+
+  it('renders all toolbar buttons', () => {
+    render(<Toolbar />);
+    expect(screen.getByTestId('toolbar-open-file')).toBeInTheDocument();
+    expect(screen.getByTestId('toolbar-open-folder')).toBeInTheDocument();
+    expect(screen.getByTestId('toolbar-save')).toBeInTheDocument();
+    expect(screen.getByTestId('toolbar-toggle-sidebar')).toBeInTheDocument();
+    expect(screen.getByTestId('toolbar-toggle-preview')).toBeInTheDocument();
+  });
+
+  it('Open file button dispatches file.open', () => {
+    const handler = vi.fn();
+    useCommandStore.getState().register('file.open', handler);
+    render(<Toolbar />);
+    fireEvent.click(screen.getByTestId('toolbar-open-file'));
+    expect(handler).toHaveBeenCalledTimes(1);
+  });
+
+  it('Open folder button dispatches file.openFolder', () => {
+    const handler = vi.fn();
+    useCommandStore.getState().register('file.openFolder', handler);
+    render(<Toolbar />);
+    fireEvent.click(screen.getByTestId('toolbar-open-folder'));
+    expect(handler).toHaveBeenCalledTimes(1);
+  });
+
+  it('Save button dispatches file.save', () => {
+    const handler = vi.fn();
+    useCommandStore.getState().register('file.save', handler);
+    render(<Toolbar />);
+    fireEvent.click(screen.getByTestId('toolbar-save'));
+    expect(handler).toHaveBeenCalledTimes(1);
+  });
+
+  it('Toggle sidebar button dispatches view.toggleSidebar and reflects aria-pressed', () => {
+    const handler = vi.fn();
+    useCommandStore.getState().register('view.toggleSidebar', handler);
+    render(<Toolbar />);
+    const btn = screen.getByTestId('toolbar-toggle-sidebar');
+    expect(btn).toHaveAttribute('aria-pressed', 'true');
+    fireEvent.click(btn);
+    expect(handler).toHaveBeenCalledTimes(1);
+  });
+
+  it('Toggle preview button dispatches view.togglePreview', () => {
+    const handler = vi.fn();
+    useCommandStore.getState().register('view.togglePreview', handler);
+    render(<Toolbar />);
+    fireEvent.click(screen.getByTestId('toolbar-toggle-preview'));
+    expect(handler).toHaveBeenCalledTimes(1);
+  });
+
+  it('toggle sidebar end-to-end: command flips appStore state, aria-pressed reflects it', () => {
+    useCommandStore.getState().register('view.toggleSidebar', () => {
+      useAppStore.getState().toggleSidebar();
+    });
+    render(<Toolbar />);
+    const btn = screen.getByTestId('toolbar-toggle-sidebar');
+    expect(btn).toHaveAttribute('aria-pressed', 'true');
+    act(() => {
+      fireEvent.click(btn);
+    });
+    expect(useAppStore.getState().sidebarVisible).toBe(false);
+    expect(btn).toHaveAttribute('aria-pressed', 'false');
+  });
+
+  it('formatting buttons (bold, italic, etc.) are disabled (Phase 9 work)', () => {
+    render(<Toolbar />);
+    expect(screen.getByLabelText('Bold')).toBeDisabled();
+    expect(screen.getByLabelText('Italic')).toBeDisabled();
+    expect(screen.getByLabelText('Unordered list')).toBeDisabled();
+    expect(screen.getByLabelText('Ordered list')).toBeDisabled();
+    expect(screen.getByLabelText('Code')).toBeDisabled();
+    expect(screen.getByLabelText('Link')).toBeDisabled();
+  });
+});

tests/component/modals/AboutDialog.test.tsx

@@ -0,0 +1,34 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { AboutDialog } from '@/components/modals/AboutDialog';
+import { useAppStore } from '@/stores/app-store';
+
+describe('AboutDialog', () => {
+  beforeEach(() => {
+    window.electronAPI = {
+      app: {
+        getVersion: vi.fn().mockResolvedValue('5.0.0'),
+        openExternal: vi.fn().mockResolvedValue({ ok: true }),
+      },
+    } as any;
+    // Reset store to about modal so dialog renders
+    useAppStore.setState({ modal: { kind: 'about' } } as any);
+  });
+
+  it('renders title and version', async () => {
+    render(<AboutDialog />);
+    expect(screen.getByText(/about markdownconverter/i)).toBeInTheDocument();
+    expect(await screen.findByText(/5\.0\.0/)).toBeInTheDocument();
+  });
+
+  it('closes when the close button is clicked', async () => {
+    render(<AboutDialog />);
+    // dialog-footer has the visible Close button; the X button also has sr-only "Close"
+    const closeButtons = await screen.findAllByRole('button', { name: /close/i });
+    const close = closeButtons[0];
+    await userEvent.click(close);
+    // closeModal sets modal.kind = null, so isOpen=false, Dialog unmounts
+    expect(screen.queryByRole('dialog')).not.toBeInTheDocument();
+  });
+});

tests/component/modals/ConfirmDialog.test.tsx

@@ -0,0 +1,43 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { ConfirmDialog } from '@/components/modals/ConfirmDialog';
+import { useAppStore } from '@/stores/app-store';
+
+describe('ConfirmDialog', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    useAppStore.setState({ modal: { kind: null } } as any);
+  });
+
+  it('renders title, body, and confirm/cancel labels', () => {
+    render(
+      <ConfirmDialog
+        title="Delete file?"
+        body="This cannot be undone."
+        confirmLabel="Delete"
+        onConfirm={() => {}}
+      />
+    );
+    expect(screen.getByText(/delete file/i)).toBeInTheDocument();
+    expect(screen.getByText(/cannot be undone/i)).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: /^delete$/i })).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: /cancel/i })).toBeInTheDocument();
+  });
+
+  it('calls onConfirm and closes on confirm click', async () => {
+    const onConfirm = vi.fn();
+    render(<ConfirmDialog title="T" body="B" onConfirm={onConfirm} />);
+    await userEvent.click(screen.getByRole('button', { name: /confirm/i }));
+    expect(onConfirm).toHaveBeenCalledTimes(1);
+    expect(useAppStore.getState().modal).toEqual({ kind: null });
+  });
+
+  it('destructive variant uses destructive button class', () => {
+    render(
+      <ConfirmDialog title="T" body="B" destructive onConfirm={() => {}} />
+    );
+    const btn = screen.getByRole('button', { name: /confirm/i });
+    expect(btn.className).toContain('bg-destructive');
+  });
+});

tests/component/modals/ExportBatchDialog.test.tsx

@@ -0,0 +1,29 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { ExportBatchDialog } from '@/components/modals/ExportBatchDialog';
+
+describe('ExportBatchDialog', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    window.electronAPI = {
+      export: { batch: vi.fn().mockResolvedValue({ ok: true, data: { total: 2, succeeded: 2, failed: 0, results: [] } }) },
+    } as any;
+  });
+
+  it('renders the file list passed via sourcePaths', () => {
+    render(<ExportBatchDialog sourcePaths={['/a.md', '/b.md']} />);
+    expect(screen.getByText('/a.md')).toBeInTheDocument();
+    expect(screen.getByText('/b.md')).toBeInTheDocument();
+  });
+
+  it('selecting format and concurrency submits correct options', async () => {
+    render(<ExportBatchDialog sourcePaths={['/a.md', '/b.md']} />);
+    await userEvent.click(screen.getByRole('combobox', { name: /format/i }));
+    await userEvent.click(screen.getByRole('option', { name: /^pdf$/i }));
+    await userEvent.click(screen.getByRole('button', { name: /^export$/i }));
+    const call = (window.electronAPI.export.batch as any).mock.calls[0];
+    expect(call[0]).toEqual([{ inputPath: '/a.md', outputPath: expect.any(String) }, { inputPath: '/b.md', outputPath: expect.any(String) }]);
+    expect(call[1].format).toBe('pdf');
+  });
+});

tests/component/modals/ExportDocxDialog.test.tsx

@@ -0,0 +1,41 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { ExportDocxDialog } from '@/components/modals/ExportDocxDialog';
+import { useFileStore } from '@/stores/file-store';
+import { useEditorStore } from '@/stores/editor-store';
+import { useSettingsStore } from '@/stores/settings-store';
+
+describe('ExportDocxDialog', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    window.electronAPI = {
+      export: { docx: vi.fn().mockResolvedValue({ ok: true, data: { outputPath: '/out.docx' } }) },
+    } as any;
+    useSettingsStore.setState(useSettingsStore.getInitialState());
+    useFileStore.setState({ activeTabId: '/test.md', openTabs: [{ id: '/test.md', path: '/test.md', title: 'test.md', dirty: false }] } as any);
+    useEditorStore.setState({ buffers: new Map([['/test.md', { id: '/test.md', path: '/test.md', content: '# hi', dirty: false }]]) } as any);
+  });
+
+  it('renders with standard template selected by default', () => {
+    render(<ExportDocxDialog sourcePath="/test.md" />);
+    expect(screen.getByText(/export to docx/i)).toBeInTheDocument();
+    expect(screen.getByRole('combobox', { name: /template/i })).toBeInTheDocument();
+  });
+
+  it('submitting with default options sends template=standard', async () => {
+    render(<ExportDocxDialog sourcePath="/test.md" />);
+    await userEvent.click(screen.getByRole('button', { name: /^export$/i }));
+    const call = (window.electronAPI.export.docx as any).mock.calls[0][0];
+    expect(call.template).toBe('standard');
+  });
+
+  it('selecting "modern" template sends template=modern', async () => {
+    render(<ExportDocxDialog sourcePath="/test.md" />);
+    await userEvent.click(screen.getByRole('combobox', { name: /template/i }));
+    await userEvent.click(screen.getByRole('option', { name: /modern/i }));
+    await userEvent.click(screen.getByRole('button', { name: /^export$/i }));
+    const call = (window.electronAPI.export.docx as any).mock.calls[0][0];
+    expect(call.template).toBe('modern');
+  });
+});