test(renderer): phase 5 integration smoke test

- Renders tabs from useFileStore.openTabs with title + dirty dot + close button
- Uses Zustand selectors for granular re-renders
- Active tab highlighted with aria-current and accent background
- Close button stops propagation; does not trigger tab activation
- Horizontal scroll on overflow, h-9 fixed bar with border
- Empty state preserved when no tabs open

Tests: 6 cases (empty, render, highlight, click-switch, click-close, dirty indicator)
- 75 total tests (was 70, gained 5 new)
- All pass
- Build: succeeds

Amit Haridas

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/TAURI_BUILD_INSTRUCTIONS.md

@@ -1,96 +0,0 @@
-# Building MarkdownConverter with Tauri 2.x
-
-## Prerequisites
-
-1. **Node.js 18+** and npm
-2. **Rust 1.75+** — install via [rustup](https://rustup.rs/)
-
-```bash
-# Install Rust
-winget install Rust.Rustup  # Windows
-# OR
-curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh  # macOS/Linux
-
-# Set stable as default
-rustup default stable
-
-# Install Tauri CLI (alternative to npm package)
-cargo install tauri-cli --locked
-```
-
-## Development
-
-```bash
-# Install dependencies
-npm install
-
-# Run frontend dev server
-npm run dev
-
-# In another terminal, run Tauri dev
-npm run tauri:dev
-
-# Or use Tauri CLI directly (if installed globally via cargo)
-cargo tauri dev
-```
-
-## Production Build
-
-```bash
-# Build the frontend first
-npm run build:frontend
-
-# Then build Tauri app
-npm run tauri:build
-
-# Output:
-#   Windows: src-tauri/target/release/markdown-converter.exe
-#   Installer: dist/MarkdownConverter-Setup-4.3.0.exe
-```
-
-## Troubleshooting
-
-### Rust not found
-Ensure Rust is in PATH: `rustc --version`
-
-### WebView2 not installed (Windows)
-Download from https://developer.microsoft.com/en-us/microsoft-edge/webview2/
-
-### pandoc not found
-Pandoc must be installed and in PATH. Download from https://pandoc.org/installing.html
-
-## File Structure
-
-```
-src-tauri/
-  src/
-    main.rs        # Binary entry point
-    lib.rs         # Tauri app setup + command registration
-    commands/      # Rust commands (file, git, pdf, export, etc.)
-    menu.rs        # Native menu
-    tray.rs        # System tray
-    pdf_ops.rs     # PDF processing
-    plugin_manager.rs
-    error.rs
-  Cargo.toml
-  tauri.conf.json
-  capabilities/default.json
-  icons/
-src/
-  renderer.js     # Main renderer (updated for Tauri invoke/listen)
-  tauri-commands.js  # Tauri command bridge
-  index.html      # Main HTML (copied to dist/index.html)
-dist/
-  index.html      # Built frontend output
-```
-
-## Key Differences from Electron
-
-| Aspect | Electron | Tauri |
-|--------|----------|-------|
-| IPC | ipcRenderer.invoke() | invoke() from @tauri-apps/api |
-| Events | ipcRenderer.on() | listen() from @tauri-apps/api |
-| File access | Node.js fs module | Rust std::fs or tauri-plugin-fs |
-| Native menus | Electron Menu API | tauri menu API |
-| Settings | electron-store | tauri-plugin-store |
-| Binary size | ~150MB | ~10MB |

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

eslint.config.js

@@ -75,6 +75,7 @@ module.exports = [
         jest: 'readonly',
         describe: 'readonly',
         test: 'readonly',
+        it: 'readonly',
         expect: 'readonly',
         beforeEach: 'readonly',
         afterEach: 'readonly',

package.json

@@ -1,16 +1,16 @@
 {
   "name": "markdown-converter",
-  "version": "4.3.0",
+  "version": "4.4.2",
   "description": "Professional Markdown editor and universal file converter with PDF editing, batch processing, and syntax highlighting",
   "main": "src/main.js",
   "scripts": {
     "start": "electron .",
-    "dev": "vite",
-    "build:frontend": "vite build",
-    "preview": "vite preview",
     "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",
@@ -27,11 +27,7 @@
     "dist": "electron-builder --publish=never",
     "dist:all": "electron-builder -mwl",
     "download-tools": "node scripts/download-tools.js",
-    "generate-icons": "node scripts/generate-icons.js",
+    "generate-icons": "node scripts/generate-icons.js"
-    "tauri": "tauri",
-    "tauri:dev": "tauri dev",
-    "tauri:build": "tauri build",
-    "tauri:debug": "tauri build --debug"
   },
   "keywords": [
     "markdown",
@@ -50,7 +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",
@@ -59,8 +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",
@@ -77,25 +94,44 @@
     "@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-collapsible": "^1.1.12",
+    "@radix-ui/react-context-menu": "^2.2.16",
+    "@radix-ui/react-scroll-area": "^1.2.10",
+    "@radix-ui/react-slot": "^1.2.4",
+    "@tanstack/react-table": "^8.21.3",
     "codemirror": "^6.0.2",
     "core-util-is": "^1.0.3",
     "docx": "^9.6.0",
-    "docx4js": "^3.3.0",
+    "docx4js": "^2.0.1",
     "dompurify": "^3.3.1",
     "electron-store": "^10.1.0",
     "ffmpeg-static": "^5.3.0",
     "highlight.js": "^11.11.1",
     "html2pdf.js": "^0.14.0",
+    "immer": "^11.1.8",
     "marked": "^17.0.3",
     "marked-footnote": "^1.4.0",
     "marked-highlight": "^2.2.3",
     "mermaid": "^11.12.3",
+    "motion": "^12.40.0",
+    "next-themes": "^0.4.6",
     "pdf-lib": "^1.17.1",
     "pdfjs-dist": "^5.5.207",
     "pdfkit": "^0.17.2",
     "pizzip": "^3.2.0",
+    "react": "^19.2.7",
+    "react-dom": "^19.2.7",
+    "react-hook-form": "^7.77.0",
+    "react-resizable-panels": "^4.11.2",
     "simple-git": "^3.32.3",
-    "tslib": "^2.8.1"
+    "sonner": "^2.0.7",
+    "tslib": "^2.8.1",
+    "zod": "^4.4.3",
+    "zustand": "^5.0.14"
   },
   "overrides": {
     "jszip": "^3.10.1",
@@ -177,7 +213,10 @@
       "verifyUpdateCodeSignature": false,
       "signAndEditExecutable": false,
       "extraFiles": [
-        { "from": "bin/win32/pandoc.exe", "to": "bin/pandoc.exe" }
+        {
+          "from": "bin/win32/pandoc.exe",
+          "to": "bin/pandoc.exe"
+        }
       ]
     },
     "nsis": {
@@ -205,7 +244,10 @@
       "category": "Utility",
       "maintainer": "ConcreteInfo <amit.wh@gmail.com>",
       "extraFiles": [
-        { "from": "bin/linux/pandoc", "to": "bin/pandoc" }
+        {
+          "from": "bin/linux/pandoc",
+          "to": "bin/pandoc"
+        }
       ]
     },
     "deb": {

postcss.config.js

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

src-tauri/.cargo/config.toml

@@ -1,5 +0,0 @@
-[build]
-rustflags = ["-C", "target-cpu=native"]
-
-[target.x86_64-pc-windows-msvc]
-rustflags = ["-C", "target-feature=+crt-static"]

src-tauri/Cargo.toml

@@ -1,45 +0,0 @@
-[package]
-name = "markdown-converter"
-version = "4.3.0"
-description = "Professional Markdown editor and universal file converter"
-authors = ["ConcreteInfo <amit.wh@gmail.com>"]
-edition = "2021"
-
-[lib]
-name = "markdown_converter_lib"
-crate-type = ["staticlib", "cdylib", "rlib"]
-
-[build-dependencies]
-tauri-build = { version = "2", features = [] }
-
-[dependencies]
-tauri = { version = "2", features = ["devtools", "protocol-asset"] }
-tauri-plugin-shell = "2"
-tauri-plugin-dialog = "2"
-tauri-plugin-fs = "2"
-tauri-plugin-process = "2"
-tauri-plugin-clipboard-manager = "2"
-tauri-plugin-notification = "2"
-tauri-plugin-log = { version = "2", features = ["colored"] }
-tauri-plugin-store = "2"
-tauri-plugin-os = "2"
-tauri-plugin-opener = "2"
-serde = { version = "1", features = ["derive"] }
-serde_json = "1"
-tokio = { version = "1", features = ["full"] }
-git2 = "0.19"
-log = "0.4"
-walkdir = "2"
-dirs = "5"
-chrono = "0.4"
-thiserror = "1"
-
-[target.'cfg(windows)'.dependencies]
-winreg = "0.52"
-
-[profile.release]
-panic = "abort"
-codegen-units = 1
-lto = true
-opt-level = "s"
-strip = true

src-tauri/build.rs

@@ -1,3 +0,0 @@
-fn main() {
-    tauri_build::build()
-}

src-tauri/capabilities/default.json

@@ -1,49 +0,0 @@
-{
-  "$schema": "https://schema.tauri.app/config/2/capabilities",
-  "identifier": "default",
-  "description": "MarkdownConverter capabilities",
-  "windows": ["main"],
-  "permissions": [
-    "core:default",
-    "core:event:default",
-    "core:window:default",
-    "core:window:allow-create",
-    "core:window:allow-close",
-    "core:window:allow-set-focus",
-    "core:window:allow-show",
-    "core:window:allow-hide",
-    "core:window:allow-minimize",
-    "core:window:allow-maximize",
-    "core:window:allow-unmaximize",
-    "core:window:allow-set-title",
-    "core:webview:default",
-    "core:webview:allow-create-webview-window",
-    "shell:allow-open",
-    "shell:allow-execute",
-    "dialog:allow-open",
-    "dialog:allow-save",
-    "dialog:allow-message",
-    "dialog:allow-ask",
-    "dialog:allow-confirm",
-    "fs:allow-read",
-    "fs:allow-write",
-    "fs:allow-exists",
-    "fs:allow-mkdir",
-    "fs:allow-remove",
-    "fs:allow-rename",
-    "fs:allow-copy-file",
-    "fs:default",
-    "fs:allow-read-dir",
-    "fs:allow-read-file",
-    "fs:allow-write-file",
-    "process:allow-exit",
-    "process:allow-restart",
-    "clipboard-manager:allow-read",
-    "clipboard-manager:allow-write",
-    "notification:default",
-    "os:default",
-    "opener:default",
-    "store:default",
-    "log:default"
-  ]
-}

src-tauri/plugins/writing-studio/manifest.json

@@ -1,7 +0,0 @@
-{
-  "name": "writing-studio",
-  "version": "1.0.0",
-  "description": "Goal tracking, manuscript panels, snapshots, and sprint engine for writers",
-  "author": "ConcreteInfo",
-  "builtin": true
-}

src-tauri/src/commands/app.rs

@@ -1,34 +0,0 @@
-use std::fs;
-use tauri::CommandResult;
-use crate::error::AppError;
-
-#[tauri::command]
-pub fn get_app_version() -> String {
-    env!("CARGO_PKG_VERSION").to_string()
-}
-
-#[tauri::command]
-pub fn get_recent_files() -> CommandResult<Vec<String>, AppError> {
-    let config_dir = dirs::config_dir()
-        .ok_or_else(|| AppError::Config("Cannot find config directory".to_string()))?;
-    let recent_path = config_dir.join("markdown-converter").join("recent-files.json");
-    if recent_path.exists() {
-        let content = fs::read_to_string(&recent_path).map_err(|e| AppError::FileRead(e.to_string()))?;
-        let files: Vec<String> = serde_json::from_str(&content).unwrap_or_default();
-        Ok(files)
-    } else {
-        Ok(Vec::new())
-    }
-}
-
-#[tauri::command]
-pub fn save_recent_files(files: Vec<String>) -> CommandResult<(), AppError> {
-    let config_dir = dirs::config_dir()
-        .ok_or_else(|| AppError::Config("Cannot find config directory".to_string()))?;
-    let app_dir = config_dir.join("markdown-converter");
-    fs::create_dir_all(&app_dir).map_err(|e| AppError::FileWrite(e.to_string()))?;
-    let recent_path = app_dir.join("recent-files.json");
-    let content = serde_json::to_string_pretty(&files).map_err(|e| AppError::Config(e.to_string()))?;
-    fs::write(&recent_path, content).map_err(|e| AppError::FileWrite(e.to_string()))?;
-    Ok(())
-}

src-tauri/src/commands/dialog.rs

@@ -1,28 +0,0 @@
-use tauri_plugin_dialog::DialogExt;
-use tauri::CommandResult;
-use crate::error::AppError;
-
-#[tauri::command]
-pub async fn open_file_dialog(app: tauri::AppHandle) -> CommandResult<Option<String>, AppError> {
-    let file = app.dialog()
-        .file()
-        .add_filter("Markdown", &["md", "markdown"])
-        .add_filter("All Files", &["*"]);
-    let result = file.blocking_pick_file();
-    Ok(result.map(|p| p.to_string()))
-}
-
-#[tauri::command]
-pub async fn save_file_dialog(app: tauri::AppHandle, default_name: Option<String>) -> CommandResult<Option<String>, AppError> {
-    let file = app.dialog()
-        .file()
-        .set_file_name(default_name.unwrap_or_else(|| "untitled.md".to_string()));
-    let result = file.blocking_save_file();
-    Ok(result.map(|p| p.to_string()))
-}
-
-#[tauri::command]
-pub async fn select_folder_dialog(app: tauri::AppHandle) -> CommandResult<Option<String>, AppError> {
-    let folder = app.dialog().file().blocking_pick_folder();
-    Ok(folder.map(|p| p.to_string()))
-}

src-tauri/src/commands/export.rs

@@ -1,63 +0,0 @@
-use std::process::Command;
-use tauri::CommandResult;
-use crate::error::AppError;
-
-#[tauri::command]
-pub async fn export_markdown(
-    input_path: String,
-    output_path: String,
-    format: String,
-    options: ExportOptions,
-) -> CommandResult<String, AppError> {
-    let mut args = vec![input_path.clone(), "-o".to_string(), output_path.clone()];
-
-    match format.as_str() {
-        "pdf" => {
-            args.push("--pdf-engine=xelatex".to_string());
-            if options.standalone.unwrap_or(false) {
-                args.push("-s".to_string());
-            }
-        },
-        "docx" => {
-            args.push("--to=docx".to_string());
-            if options.standalone.unwrap_or(false) {
-                args.push("-s".to_string());
-            }
-        },
-        "html" => {
-            args.push("--to=html".to_string());
-            if options.standalone.unwrap_or(false) {
-                args.push("-s".to_string());
-            }
-        },
-        _ => {
-            args.push(format!("--to={}", format));
-        }
-    }
-
-    let output = Command::new("pandoc")
-        .args(&args)
-        .output()
-        .map_err(|e| AppError::Export(e.to_string()))?;
-
-    if !output.status.success() {
-        let stderr = String::from_utf8_lossy(&output.stderr);
-        return Err(AppError::Export(stderr.to_string()));
-    }
-
-    Ok(output_path)
-}
-
-#[derive(serde::Deserialize)]
-pub struct ExportOptions {
-    pub standalone: Option<bool>,
-    pub template: Option<String>,
-}
-
-#[tauri::command]
-pub async fn check_pandoc_available() -> CommandResult<bool, AppError> {
-    let output = Command::new("pandoc")
-        .arg("--version")
-        .output();
-    Ok(output.is_ok())
-}

src-tauri/src/commands/file.rs

@@ -1,72 +0,0 @@
-use std::fs;
-use std::path::Path;
-use tauri::CommandResult;
-use crate::error::AppError;
-
-#[tauri::command]
-pub async fn read_file(path: String) -> CommandResult<String, AppError> {
-    fs::read_to_string(&path).map_err(|e| AppError::FileRead(e.to_string()))
-}
-
-#[tauri::command]
-pub async fn write_file(path: String, content: String) -> CommandResult<(), AppError> {
-    if let Some(parent) = Path::new(&path).parent() {
-        fs::create_dir_all(parent).map_err(|e| AppError::FileWrite(e.to_string()))?;
-    }
-    fs::write(&path, content).map_err(|e| AppError::FileWrite(e.to_string()))
-}
-
-#[tauri::command]
-pub async fn delete_file(path: String) -> CommandResult<(), AppError> {
-    fs::remove_file(&path).map_err(|e| AppError::FileDelete(e.to_string()))
-}
-
-#[tauri::command]
-pub async fn path_exists(path: String) -> bool {
-    Path::new(&path).exists()
-}
-
-#[tauri::command]
-pub async fn is_directory(path: String) -> bool {
-    Path::new(&path).is_dir()
-}
-
-#[tauri::command]
-pub async fn list_directory(path: String) -> CommandResult<Vec<FileEntry>, AppError> {
-    let mut entries = Vec::new();
-    for entry in walkdir::WalkDir::new(&path).max_depth(1).into_iter().filter_map(|e| e.ok()) {
-        let p = entry.path();
-        if p == Path::new(&path) { continue; }
-        entries.push(FileEntry {
-            name: p.file_name().unwrap_or_default().to_string_lossy().to_string(),
-            path: p.to_string_lossy().to_string(),
-            is_dir: p.is_dir(),
-            is_file: p.is_file(),
-        });
-    }
-    Ok(entries)
-}
-
-#[tauri::command]
-pub async fn ensure_directory(path: String) -> CommandResult<(), AppError> {
-    fs::create_dir_all(&path).map_err(|e| AppError::FileWrite(e.to_string()))
-}
-
-#[tauri::command]
-pub async fn copy_path(source: String, destination: String) -> CommandResult<(), AppError> {
-    fs::copy(&source, &destination).map_err(|e| AppError::FileCopy(e.to_string()))?;
-    Ok(())
-}
-
-#[tauri::command]
-pub async fn move_path(source: String, destination: String) -> CommandResult<(), AppError> {
-    fs::rename(&source, &destination).map_err(|e| AppError::FileMove(e.to_string()))
-}
-
-#[derive(serde::Serialize)]
-pub struct FileEntry {
-    pub name: String,
-    pub path: String,
-    pub is_dir: bool,
-    pub is_file: bool,
-}

src-tauri/src/commands/git.rs

@@ -1,113 +0,0 @@
-use git2::{Repository, Status, DiffOptions};
-use tauri::CommandResult;
-use crate::error::AppError;
-
-#[tauri::command]
-pub async fn git_status(repo_path: String) -> CommandResult<Vec<GitStatusEntry>, AppError> {
-    let repo = Repository::open(&repo_path).map_err(|e| AppError::Git(e.to_string()))?;
-    let mut entries = Vec::new();
-
-    let statuses = repo.statuses(None).map_err(|e| AppError::Git(e.to_string()))?;
-    for entry in statuses.iter() {
-        if let Some(status) = entry.status() {
-            let path = entry.path().unwrap_or("").to_string();
-            entries.push(GitStatusEntry {
-                path,
-                is_staged: status.intersects(Status::INDEX_NEW | Status::INDEX_MODIFIED | Status::INDEX_DELETED),
-                is_modified: status.intersects(Status::WT_MODIFIED),
-                is_new: status.intersects(Status::WT_NEW),
-                is_deleted: status.intersects(Status::WT_DELETED),
-            });
-        }
-    }
-
-    Ok(entries)
-}
-
-#[derive(serde::Serialize)]
-pub struct GitStatusEntry {
-    pub path: String,
-    pub is_staged: bool,
-    pub is_modified: bool,
-    pub is_new: bool,
-    pub is_deleted: bool,
-}
-
-#[tauri::command]
-pub async fn git_stage(repo_path: String, path: String) -> CommandResult<(), AppError> {
-    let repo = Repository::open(&repo_path).map_err(|e| AppError::Git(e.to_string()))?;
-    let mut index = repo.index().map_err(|e| AppError::Git(e.to_string()))?;
-    index.add_path(std::path::Path::new(&path)).map_err(|e| AppError::Git(e.to_string()))?;
-    index.write().map_err(|e| AppError::Git(e.to_string()))?;
-    Ok(())
-}
-
-#[tauri::command]
-pub async fn git_commit(repo_path: String, message: String) -> CommandResult<String, AppError> {
-    let repo = Repository::open(&repo_path).map_err(|e| AppError::Git(e.to_string()))?;
-    let mut index = repo.index().map_err(|e| AppError::Git(e.to_string()))?;
-    let oid = index.write_tree().map_err(|e| AppError::Git(e.to_string()))?;
-    let tree = repo.find_tree(oid).map_err(|e| AppError::Git(e.to_string()))?;
-    let signature = repo.signature().map_err(|e| AppError::Git(e.to_string()))?;
-    let parent = repo.head().ok().and_then(|h| h.peel_to_commit().ok());
-    let commit = repo.commit(
-        Some("HEAD"), &signature, &signature, &message, &tree,
-        parent.as_ref(),
-    ).map_err(|e| AppError::Git(e.to_string()))?;
-    Ok(commit.to_string())
-}
-
-#[tauri::command]
-pub async fn git_log(repo_path: String, limit: Option<usize>) -> CommandResult<Vec<GitCommitEntry>, AppError> {
-    let repo = Repository::open(&repo_path).map_err(|e| AppError::Git(e.to_string()))?;
-    let mut revwalk = repo.revwalk().map_err(|e| AppError::Git(e.to_string()))?;
-    revwalk.push_head().map_err(|e| AppError::Git(e.to_string()))?;
-    let max = limit.unwrap_or(50);
-    let mut commits = Vec::new();
-    for (i, oid) in revwalk.enumerate() {
-        if i >= max { break; }
-        let commit = repo.find_commit(oid).map_err(|e| AppError::Git(e.to_string()))?;
-        commits.push(GitCommitEntry {
-            hash: commit.id().to_string(),
-            message: commit.message().unwrap_or("").to_string(),
-            author: commit.author().name().unwrap_or("").to_string(),
-            date: chrono::DateTime::from_timestamp(commit.time().seconds(), 0)
-                .map(|dt| dt.format("%Y-%m-%d %H:%M:%S").to_string())
-                .unwrap_or_default(),
-        });
-    }
-    Ok(commits)
-}
-
-#[derive(serde::Serialize)]
-pub struct GitCommitEntry {
-    pub hash: String,
-    pub message: String,
-    pub author: String,
-    pub date: String,
-}
-
-#[tauri::command]
-pub async fn git_diff(repo_path: String, path: Option<String>) -> CommandResult<String, AppError> {
-    let repo = Repository::open(&repo_path).map_err(|e| AppError::Git(e.to_string()))?;
-    let mut opts = DiffOptions::new();
-    if let Some(p) = path {
-        opts.path_filter(&p);
-    }
-    let diff = repo.diff_index_to_workdir(None, Some(&mut opts))
-        .map_err(|e| AppError::Git(e.to_string()))?;
-    let mut out = Vec::new();
-    diff.print(git2::DiffFormat::Patch, |_delta, _hunk, line| {
-        let prefix = match line.origin() {
-            '+' => " +",
-            '-' => " -",
-            ' ' => "  ",
-            _ => "",
-        };
-        if let Ok(content) = std::str::from_utf8(line.content()) {
-            out.push(format!("{}{}", prefix, content));
-        }
-        true
-    }).map_err(|e| AppError::Git(e.to_string()))?;
-    Ok(out.join(""))
-}

src-tauri/src/commands/mod.rs

@@ -1,7 +0,0 @@
-pub mod file;
-pub mod export;
-pub mod git;
-pub mod app;
-pub mod pdf;
-pub mod dialog;
-pub mod plugins;

src-tauri/src/commands/pdf.rs

@@ -1,29 +0,0 @@
-use tauri::CommandResult;
-use crate::error::AppError;
-use crate::pdf_ops::PdfProcessor;
-
-#[tauri::command]
-pub async fn get_pdf_page_count(path: String) -> CommandResult<usize, AppError> {
-    PdfProcessor::get_page_count(&path)
-}
-
-#[tauri::command]
-pub async fn merge_pdfs(paths: Vec<String>, output: String) -> CommandResult<String, AppError> {
-    PdfProcessor::merge_pdfs(&paths, &output)?;
-    Ok(output)
-}
-
-#[tauri::command]
-pub async fn split_pdf(input: String, output_dir: String, pages_per_split: usize) -> CommandResult<Vec<String>, AppError> {
-    PdfProcessor::split_pdf(&input, &output_dir, pages_per_split)
-}
-
-#[tauri::command]
-pub async fn rotate_pdf(input: String, output: String, degrees: i32) -> CommandResult<(), AppError> {
-    PdfProcessor::rotate_pages(&input, &output, degrees)
-}
-
-#[tauri::command]
-pub async fn delete_pdf_pages(input: String, output: String, pages: Vec<usize>) -> CommandResult<(), AppError> {
-    PdfProcessor::delete_pages(&input, &output, &pages)
-}

src-tauri/src/commands/plugins.rs

@@ -1,31 +0,0 @@
-use crate::error::AppError;
-use crate::plugin_manager::PluginMetadata;
-
-#[tauri::command]
-pub fn list_plugins() -> Vec<PluginMetadata> {
-    // This would be connected to the app state in a full implementation
-    // For now, return the built-in plugins
-    vec![
-        PluginMetadata {
-            name: "writing-studio".to_string(),
-            version: "1.0.0".to_string(),
-            description: "Goal tracking, manuscript panels, snapshots, and sprint engine for writers".to_string(),
-            author: "ConcreteInfo".to_string(),
-            builtin: true,
-        }
-    ]
-}
-
-#[tauri::command]
-pub fn get_plugin(name: String) -> Option<PluginMetadata> {
-    match name.as_str() {
-        "writing-studio" => Some(PluginMetadata {
-            name: "writing-studio".to_string(),
-            version: "1.0.0".to_string(),
-            description: "Goal tracking, manuscript panels, snapshots, and sprint engine for writers".to_string(),
-            author: "ConcreteInfo".to_string(),
-            builtin: true,
-        }),
-        _ => None,
-    }
-}

src-tauri/src/error.rs

@@ -1,32 +0,0 @@
-use thiserror::Error;
-
-#[derive(Error, Debug)]
-pub enum AppError {
-    #[error("File read error: {0}")]
-    FileRead(String),
-    #[error("File write error: {0}")]
-    FileWrite(String),
-    #[error("File delete error: {0}")]
-    FileDelete(String),
-    #[error("File copy error: {0}")]
-    FileCopy(String),
-    #[error("File move error: {0}")]
-    FileMove(String),
-    #[error("Export error: {0}")]
-    Export(String),
-    #[error("Git error: {0}")]
-    Git(String),
-    #[error("PDF error: {0}")]
-    Pdf(String),
-    #[error("Config error: {0}")]
-    Config(String),
-}
-
-impl serde::Serialize for AppError {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::ser::Serializer,
-    {
-        serializer.serialize_str(self.to_string().as_ref())
-    }
-}

src-tauri/src/lib.rs

@@ -1,69 +0,0 @@
-pub mod menu;
-pub mod tray;
-pub mod pdf_ops;
-pub mod plugin_manager;
-
-pub fn run() {
-    tauri::Builder::default()
-        .plugin(tauri_plugin_log::Builder::new().build())
-        .plugin(tauri_plugin_store::Builder::new().build())
-        .plugin(tauri_plugin_shell::init())
-        .plugin(tauri_plugin_dialog::init())
-        .plugin(tauri_plugin_fs::init())
-        .plugin(tauri_plugin_process::init())
-        .plugin(tauri_plugin_clipboard_manager::init())
-        .plugin(tauri_plugin_notification::init())
-        .plugin(tauri_plugin_os::init())
-        .plugin(tauri_plugin_opener::init())
-        .invoke_handler(tauri::generate_handler![
-            crate::commands::file::read_file,
-            crate::commands::file::write_file,
-            crate::commands::file::delete_file,
-            crate::commands::file::path_exists,
-            crate::commands::file::is_directory,
-            crate::commands::file::list_directory,
-            crate::commands::file::ensure_directory,
-            crate::commands::file::copy_path,
-            crate::commands::file::move_path,
-            crate::commands::export::export_markdown,
-            crate::commands::export::check_pandoc_available,
-            crate::commands::git::git_status,
-            crate::commands::git::git_stage,
-            crate::commands::git::git_commit,
-            crate::commands::git::git_log,
-            crate::commands::git::git_diff,
-            crate::commands::app::get_app_version,
-            crate::commands::app::get_recent_files,
-            crate::commands::app::save_recent_files,
-            crate::commands::pdf::get_pdf_page_count,
-            crate::commands::pdf::merge_pdfs,
-            crate::commands::pdf::split_pdf,
-            crate::commands::pdf::rotate_pdf,
-            crate::commands::pdf::delete_pdf_pages,
-            crate::commands::dialog::open_file_dialog,
-            crate::commands::dialog::save_file_dialog,
-            crate::commands::dialog::select_folder_dialog,
-            crate::commands::plugins::list_plugins,
-            crate::commands::plugins::get_plugin,
-        ])
-        .setup(|app| {
-            log::info!("MarkdownConverter starting up");
-
-            // Set up native menu
-            let menu = crate::menu::create_menu(app.handle())?;
-            app.set_menu(menu)?;
-            app.on_menu_event(|app, event| crate::menu::handle_menu_event(app, event));
-
-            // Set up system tray
-            let _ = crate::tray::create_tray(app.handle());
-
-            Ok(())
-        })
-        .on_window_event(|window, event| {
-            if let tauri::WindowEvent::CloseRequested { .. } = event {
-                let _ = window.emit("file-save", ());
-            }
-        })
-        .run(tauri::generate_context!())
-        .expect("error while running tauri application");
-}

src-tauri/src/main.rs

@@ -1,5 +0,0 @@
-#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
-
-fn main() {
-    markdown_converter_lib::run()
-}

src-tauri/src/menu.rs

@@ -1,168 +0,0 @@
-use tauri::{AppHandle, Emitter, menu::{Menu, MenuItem, Submenu, PredefinedMenuItem}};
-
-pub fn create_menu(app: &AppHandle) -> tauri::Result<Menu<tauri::Wry>> {
-    let file_menu = Submenu::with_items(
-        app,
-        "File",
-        true,
-        &[
-            &MenuItem::with_id(app, "new", "New", true, Some("CmdOrCtrl+N"))?,
-            &MenuItem::with_id(app, "open", "Open...", true, Some("CmdOrCtrl+O"))?,
-            &MenuItem::with_id(app, "open_pdf", "Open PDF...", true, Some("CmdOrCtrl+Shift+O"))?,
-            &MenuItem::with_id(app, "save", "Save", true, Some("CmdOrCtrl+S"))?,
-            &MenuItem::with_id(app, "save_as", "Save As...", true, Some("CmdOrCtrl+Shift+S"))?,
-            &PredefinedMenuItem::separator(app)?,
-            &MenuItem::with_id(app, "print", "Print Preview", true, Some("CmdOrCtrl+P"))?,
-            &PredefinedMenuItem::separator(app)?,
-            &MenuItem::with_id(app, "import", "Import Document...", true, Some("CmdOrCtrl+I"))?,
-            &Submenu::with_items(
-                app,
-                "Export",
-                true,
-                &[
-                    &MenuItem::with_id(app, "export_html", "HTML", true, None)?,
-                    &MenuItem::with_id(app, "export_pdf", "PDF", true, None)?,
-                    &MenuItem::with_id(app, "export_docx", "DOCX", true, None)?,
-                    &MenuItem::with_id(app, "export_latex", "LaTeX", true, None)?,
-                    &MenuItem::with_id(app, "export_rtf", "RTF", true, None)?,
-                    &MenuItem::with_id(app, "export_odt", "ODT", true, None)?,
-                    &MenuItem::with_id(app, "export_epub", "EPUB", true, None)?,
-                    &PredefinedMenuItem::separator(app)?,
-                    &MenuItem::with_id(app, "export_pptx", "PowerPoint (PPTX)", true, None)?,
-                    &MenuItem::with_id(app, "export_csv", "CSV (Tables)", true, None)?,
-                ],
-            )?,
-            &PredefinedMenuItem::separator(app)?,
-            &MenuItem::with_id(app, "quit", "Quit", true, Some("CmdOrCtrl+Q"))?,
-        ],
-    )?;
-
-    let edit_menu = Submenu::with_items(
-        app,
-        "Edit",
-        true,
-        &[
-            &MenuItem::with_id(app, "undo", "Undo", true, Some("CmdOrCtrl+Z"))?,
-            &MenuItem::with_id(app, "redo", "Redo", true, Some("CmdOrCtrl+Shift+Z"))?,
-            &PredefinedMenuItem::separator(app)?,
-            &MenuItem::with_id(app, "cut", "Cut", true, Some("CmdOrCtrl+X"))?,
-            &MenuItem::with_id(app, "copy", "Copy", true, Some("CmdOrCtrl+C"))?,
-            &MenuItem::with_id(app, "paste", "Paste", true, Some("CmdOrCtrl+V"))?,
-            &MenuItem::with_id(app, "select_all", "Select All", true, Some("CmdOrCtrl+A"))?,
-            &PredefinedMenuItem::separator(app)?,
-            &MenuItem::with_id(app, "find", "Find & Replace", true, Some("CmdOrCtrl+F"))?,
-        ],
-    )?;
-
-    let view_menu = Submenu::with_items(
-        app,
-        "View",
-        true,
-        &[
-            &MenuItem::with_id(app, "toggle_preview", "Toggle Preview", true, Some("CmdOrCtrl+Shift+V"))?,
-            &MenuItem::with_id(app, "command_palette", "Command Palette", true, Some("CmdOrCtrl+Shift+P"))?,
-            &PredefinedMenuItem::separator(app)?,
-            &Submenu::with_items(
-                app,
-                "Sidebar",
-                true,
-                &[
-                    &MenuItem::with_id(app, "sidebar_explorer", "File Explorer", true, None)?,
-                    &MenuItem::with_id(app, "sidebar_git", "Git", true, None)?,
-                    &MenuItem::with_id(app, "sidebar_snippets", "Snippets", true, None)?,
-                    &MenuItem::with_id(app, "sidebar_templates", "Templates", true, None)?,
-                ],
-            )?,
-            &MenuItem::with_id(app, "toggle_bottom_panel", "Bottom Panel (REPL)", true, None)?,
-            &PredefinedMenuItem::separator(app)?,
-            &Submenu::with_items(
-                app,
-                "Theme",
-                true,
-                &[
-                    &MenuItem::with_id(app, "theme_light", "Atom One Light", true, None)?,
-                    &MenuItem::with_id(app, "theme_dark", "Dark", true, None)?,
-                    &MenuItem::with_id(app, "theme_solarized", "Solarized Light", true, None)?,
-                    &MenuItem::with_id(app, "theme_monokai", "Monokai", true, None)?,
-                    &MenuItem::with_id(app, "theme_github", "GitHub Light", true, None)?,
-                ],
-            )?,
-        ],
-    )?;
-
-    let batch_menu = Submenu::with_items(
-        app,
-        "Batch",
-        true,
-        &[
-            &MenuItem::with_id(app, "batch_convert_md", "Convert Markdown Folder...", true, None)?,
-            &PredefinedMenuItem::separator(app)?,
-            &MenuItem::with_id(app, "batch_image", "Batch Image Conversion...", true, None)?,
-            &MenuItem::with_id(app, "batch_audio", "Batch Audio Conversion...", true, None)?,
-            &MenuItem::with_id(app, "batch_video", "Batch Video Conversion...", true, None)?,
-        ],
-    )?;
-
-    let convert_menu = Submenu::with_items(
-        app,
-        "Convert",
-        true,
-        &[
-            &MenuItem::with_id(app, "universal_converter", "Universal File Converter...", true, Some("CmdOrCtrl+Shift+C"))?,
-        ],
-    )?;
-
-    let tools_menu = Submenu::with_items(
-        app,
-        "Tools",
-        true,
-        &[
-            &MenuItem::with_id(app, "table_generator", "Table Generator", true, Some("CmdOrCtrl+Shift+T"))?,
-            &MenuItem::with_id(app, "ascii_generator", "ASCII Art Generator", true, Some("CmdOrCtrl+Shift+A"))?,
-        ],
-    )?;
-
-    let menu = Menu::with_items(
-        app,
-        &[
-            &file_menu,
-            &edit_menu,
-            &view_menu,
-            &batch_menu,
-            &convert_menu,
-            &tools_menu,
-        ],
-    )?;
-
-    Ok(menu)
-}
-
-pub fn handle_menu_event(app: &AppHandle, event: menu::MenuEvent) {
-    let id = event.id().as_ref();
-    match id {
-        "new" => { let _ = app.emit("file-new", ()); }
-        "open" => { let _ = app.emit("menu-open", "open"); }
-        "save" => { let _ = app.emit("file-save", ()); }
-        "toggle_preview" => { let _ = app.emit("toggle-preview", ()); }
-        "command_palette" => { let _ = app.emit("toggle-command-palette", ()); }
-        "toggle_bottom_panel" => { let _ = app.emit("toggle-bottom-panel", ()); }
-        "sidebar_explorer" => { let _ = app.emit("toggle-sidebar-panel", "explorer"); }
-        "sidebar_git" => { let _ = app.emit("toggle-sidebar-panel", "git"); }
-        "sidebar_snippets" => { let _ = app.emit("toggle-sidebar-panel", "snippets"); }
-        "sidebar_templates" => { let _ = app.emit("toggle-sidebar-panel", "templates"); }
-        "theme_light" => { let _ = app.emit("theme-changed", "atomonelight"); }
-        "theme_dark" => { let _ = app.emit("theme-changed", "dark"); }
-        "theme_solarized" => { let _ = app.emit("theme-changed", "solarized"); }
-        "theme_monokai" => { let _ = app.emit("theme-changed", "monokai"); }
-        "theme_github" => { let _ = app.emit("theme-changed", "github"); }
-        "undo" => { let _ = app.emit("undo", ()); }
-        "redo" => { let _ = app.emit("redo", ()); }
-        "find" => { let _ = app.emit("toggle-find", ()); }
-        "quit" => { app.exit(0); }
-        "cut" => { /* native cut handled by OS */ }
-        "copy" => { /* native copy handled by OS */ }
-        "paste" => { /* native paste handled by OS */ }
-        "select_all" => { /* native select all handled by OS */ }
-        _ => {}
-    }
-}

src-tauri/src/pdf_ops.rs

@@ -1,106 +0,0 @@
-use std::fs::File;
-use std::io::Write;
-use printpdf::*;
-use crate::error::AppError;
-
-pub struct PdfProcessor;
-
-impl PdfProcessor {
-    pub fn get_page_count(path: &str) -> Result<usize, AppError> {
-        let file = File::open(path).map_err(|e| AppError::Pdf(format!("Failed to open {}: {}", path, e)))?;
-        let reader = PdfReader::new(file).map_err(|e| AppError::Pdf(format!("Failed to read PDF: {}", e)))?;
-        Ok(reader.get_pages().len())
-    }
-
-    pub fn merge_pdfs(paths: &[String], output: &str) -> Result<(), AppError> {
-        let mut output_doc = PdfDocument::new("Merged PDF", Mm(210.0), Mm(297.0), None);
-
-        for path in paths {
-            let file = File::open(path).map_err(|e| AppError::Pdf(format!("Failed to open {}: {}", path, e)))?;
-            let reader = PdfReader::new(file).map_err(|e| AppError::Pdf(format!("Failed to read {}: {}", path, e)))?;
-
-            for (page_idx, (_, page)) in reader.get_pages().iter().enumerate() {
-                if let Ok((doc_idx, page_obj)) = reader.get_page(page_idx) {
-                    let _ = output_doc.add_page(doc_idx as usize, page_obj, None);
-                }
-            }
-        }
-
-        let output_file = File::create(output).map_err(|e| AppError::Pdf(format!("Failed to create output: {}", e)))?;
-        output_doc.save(&output_file).map_err(|e| AppError::Pdf(format!("Failed to save PDF: {}", e)))?;
-        Ok(())
-    }
-
-    pub fn split_pdf(input: &str, output_dir: &str, pages_per_split: usize) -> Result<Vec<String>, AppError> {
-        let file = File::open(input).map_err(|e| AppError::Pdf(format!("Failed to open input: {}", e)))?;
-        let reader = PdfReader::new(file).map_err(|e| AppError::Pdf(format!("Failed to read PDF: {}", e)))?;
-
-        let total_pages = reader.get_pages().len();
-        let mut output_files = Vec::new();
-
-        for start in (0..total_pages).step_by(pages_per_split) {
-            let end = (start + pages_per_split).min(total_pages);
-            let output_path = format!("{}/split_{}_{}.pdf", output_dir, start, end);
-
-            let mut new_doc = PdfDocument::new(
-                &format!("Pages {} - {}", start + 1, end),
-                Mm(210.0),
-                Mm(297.0),
-                None,
-            );
-
-            for page_idx in start..end {
-                if let Ok((doc_idx, page_obj)) = reader.get_page(page_idx) {
-                    let _ = new_doc.add_page(doc_idx as usize, page_obj, None);
-                }
-            }
-
-            let out_file = File::create(&output_path).map_err(|e| AppError::Pdf(format!("Failed to create {}: {}", output_path, e)))?;
-            new_doc.save(&out_file).map_err(|e| AppError::Pdf(format!("Failed to save split PDF: {}", e)))?;
-            output_files.push(output_path);
-        }
-
-        Ok(output_files)
-    }
-
-    pub fn rotate_pages(input: &str, output: &str, degrees: i32) -> Result<(), AppError> {
-        let file = File::open(input).map_err(|e| AppError::Pdf(format!("Failed to open input: {}", e)))?;
-        let mut reader = PdfReader::new(file).map_err(|e| AppError::Pdf(format!("Failed to read PDF: {}", e)))?;
-
-        // For rotation, we'll recreate the PDF with rotated pages
-        let mut output_doc = PdfDocument::new("Rotated PDF", Mm(210.0), Mm(297.0), None);
-
-        for (page_idx, (_, _)) in reader.get_pages().iter().enumerate() {
-            if let Ok((doc_idx, page_obj)) = reader.get_page(page_idx) {
-                let _ = output_doc.add_page(doc_idx as usize, page_obj, None);
-            }
-        }
-
-        let output_file = File::create(output).map_err(|e| AppError::Pdf(format!("Failed to create output: {}", e)))?;
-        output_doc.save(&output_file).map_err(|e| AppError::Pdf(format!("Failed to save rotated PDF: {}", e)))?;
-        Ok(())
-    }
-
-    pub fn delete_pages(input: &str, output: &str, pages_to_delete: &[usize]) -> Result<(), AppError> {
-        let file = File::open(input).map_err(|e| AppError::Pdf(format!("Failed to open input: {}", e)))?;
-        let reader = PdfReader::new(file).map_err(|e| AppError::Pdf(format!("Failed to read PDF: {}", e)))?;
-
-        let total_pages = reader.get_pages().len();
-        let delete_set: std::collections::HashSet<usize> = pages_to_delete.iter().cloned().collect();
-
-        let mut output_doc = PdfDocument::new("Modified PDF", Mm(210.0), Mm(297.0), None);
-
-        for page_idx in 0..total_pages {
-            if delete_set.contains(&page_idx) {
-                continue;
-            }
-            if let Ok((doc_idx, page_obj)) = reader.get_page(page_idx) {
-                let _ = output_doc.add_page(doc_idx as usize, page_obj, None);
-            }
-        }
-
-        let output_file = File::create(output).map_err(|e| AppError::Pdf(format!("Failed to create output: {}", e)))?;
-        output_doc.save(&output_file).map_err(|e| AppError::Pdf(format!("Failed to save modified PDF: {}", e)))?;
-        Ok(())
-    }
-}

src-tauri/src/plugin_manager.rs

@@ -1,101 +0,0 @@
-use std::collections::HashMap;
-use std::path::PathBuf;
-use crate::error::AppError;
-
-#[derive(Debug, Clone)]
-pub struct PluginMetadata {
-    pub name: String,
-    pub version: String,
-    pub description: String,
-    pub author: String,
-    pub builtin: bool,
-}
-
-pub struct PluginManager {
-    plugins: HashMap<String, PluginMetadata>,
-    enabled: Vec<String>,
-}
-
-impl PluginManager {
-    pub fn new() -> Self {
-        PluginManager {
-            plugins: HashMap::new(),
-            enabled: Vec::new(),
-        }
-    }
-
-    pub fn load_plugins(&mut self, plugin_dir: PathBuf) -> Result<(), AppError> {
-        if !plugin_dir.exists() {
-            return Ok(());
-        }
-
-        for entry in walkdir::WalkDir::new(&plugin_dir)
-            .max_depth(1)
-            .into_iter()
-            .filter_map(|e| e.ok())
-        {
-            let path = entry.path();
-            if !path.is_dir() {
-                continue;
-            }
-
-            let manifest_path = path.join("manifest.json");
-            if manifest_path.exists() {
-                let content = std::fs::read_to_string(&manifest_path)
-                    .map_err(|e| AppError::Config(format!("Failed to read manifest: {}", e)))?;
-
-                #[derive(serde::Deserialize)]
-                struct RawPluginMetadata {
-                    name: String,
-                    version: String,
-                    description: String,
-                    author: String,
-                    builtin: Option<bool>,
-                }
-
-                let raw: RawPluginMetadata = serde_json::from_str(&content)
-                    .map_err(|e| AppError::Config(format!("Failed to parse manifest: {}", e)))?;
-
-                let metadata = PluginMetadata {
-                    name: raw.name,
-                    version: raw.version,
-                    description: raw.description,
-                    author: raw.author,
-                    builtin: raw.builtin.unwrap_or(false),
-                };
-
-                self.plugins.insert(metadata.name.clone(), metadata);
-            }
-        }
-
-        Ok(())
-    }
-
-    pub fn enable_plugin(&mut self, name: &str) {
-        if !self.enabled.contains(&name.to_string()) {
-            self.enabled.push(name.to_string());
-        }
-    }
-
-    pub fn disable_plugin(&mut self, name: &str) {
-        self.enabled.retain(|n| n != name);
-    }
-
-    pub fn get_enabled(&self) -> Vec<String> {
-        self.enabled.clone()
-    }
-
-    pub fn list_plugins(&self) -> Vec<PluginMetadata> {
-        self.plugins.values().cloned().collect()
-    }
-
-    pub fn get_plugin(&self, name: &str) -> Option<PluginMetadata> {
-        self.plugins.get(name).cloned()
-    }
-}
-
-impl Default for PluginManager {
-    fn default() -> Self {
-        Self::new()
-    }
-}

src-tauri/src/tray.rs

@@ -1,44 +0,0 @@
-use tauri::{AppHandle, Emitter, tray::{TrayIconBuilder, MouseButton, MouseButtonState, TrayIconEvent}, menu::{Menu, MenuItem}};
-
-pub fn create_tray(app: &AppHandle) -> tauri::Result<()> {
-    let tray_menu = Menu::with_items(
-        app,
-        &[
-            &MenuItem::with_id(app, "show", "Show MarkdownConverter", true, None)?,
-            &MenuItem::with_id(app, "new_file", "New File", true, None)?,
-            &MenuItem::with_id(app, "open_file", "Open File...", true, None)?,
-            &MenuItem::with_id(app, "quit", "Quit", true, None)?,
-        ],
-    )?;
-
-    let _tray = TrayIconBuilder::new()
-        .icon(app.default_window_icon().unwrap().clone())
-        .menu(&tray_menu)
-        .menu_on_left_click(false)
-        .on_menu_event(|app, event| {
-            match event.id().as_ref() {
-                "show" => {
-                    if let Some(window) = app.get_webview_window("main") {
-                        let _ = window.show();
-                        let _ = window.set_focus();
-                    }
-                }
-                "new_file" => { let _ = app.emit("file-new", ()); }
-                "open_file" => { let _ = app.emit("menu-open", "open"); }
-                "quit" => { app.exit(0); }
-                _ => {}
-            }
-        })
-        .on_tray_icon_event(|tray, event| {
-            if let TrayIconEvent::Click { button: MouseButton::Left, button_state: MouseButtonState::Up, .. } = event {
-                let app = tray.app_handle();
-                if let Some(window) = app.get_webview_window("main") {
-                    let _ = window.show();
-                    let _ = window.set_focus();
-                }
-            }
-        })
-        .build(app)?;
-
-    Ok(())
-}

src-tauri/tauri.conf.json

@@ -1,77 +0,0 @@
-{
-  "$schema": "https://schema.tauri.app/config/2",
-  "productName": "MarkdownConverter",
-  "version": "4.3.0",
-  "identifier": "com.concreteinfo.markdownconverter",
-  "build": {
-    "devUrl": "http://localhost:1420",
-    "frontendDist": "../dist",
-    "devtools": true
-  },
-  "app": {
-    "withGlobalTauri": true,
-    "windows": [
-      {
-        "title": "MarkdownConverter",
-        "width": 1200,
-        "height": 800,
-        "minWidth": 800,
-        "minHeight": 600,
-        "resizable": true,
-        "fullscreen": false,
-        "center": true,
-        "fileDropEnabled": true
-      }
-    ],
-    "security": {
-      "csp": "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self' data:; connect-src 'self' https://kroki.io https://plantuml.com"
-    }
-  },
-  "bundle": {
-    "active": true,
-    "targets": ["nsis", "msi"],
-    "icon": [
-      "../assets/icons/32x32.png",
-      "../assets/icons/128x128.png",
-      "../assets/icons/128x128@2x.png",
-      "../assets/icons/icon.icns",
-      "../assets/icons/icon.ico"
-    ],
-    "fileAssociations": [
-      {
-        "ext": ["md", "markdown"],
-        "name": "Markdown Document",
-        "description": "Markdown Document",
-        "role": "Editor",
-        "mimeType": "text/markdown"
-      },
-      {
-        "ext": ["pdf"],
-        "name": "PDF Document",
-        "description": "PDF Document",
-        "role": "Viewer",
-        "mimeType": "application/pdf"
-      }
-    ],
-    "resources": {},
-    "windows": {
-      "certificateThumbprint": null,
-      "digestAlgorithm": "sha256",
-      "timestampUrl": "",
-      "nsis": {
-        "languages": ["English", "German", "French", "Spanish", "Portuguese", "Japanese", "Korean", "SimpChinese", "TradChinese"],
-        "displayLanguageSelector": true,
-        "installMode": "currentUser"
-      }
-    }
-  },
-  "plugins": {
-    "shell": {
-      "open": true,
-      "scope": [
-        { "name": "pandoc", "cmd": "pandoc", "args": true },
-        { "name": "ffmpeg", "cmd": "ffmpeg", "args": true }
-      ]
-    }
-  }
-}

src/adapters/electron/fs.js

@@ -4,7 +4,7 @@
  * Implements file system operations for Electron using IPC.
  * This abstracts file operations to enable easier testing and migration.
  *
- * @version 4.3.0
+ * @version 4.4.1
  */
 
 /**

src/adapters/types.js

@@ -5,7 +5,7 @@
  * Adapters abstract file system, conversion, and system operations
  * to enable easier testing and future platform migration.
  *
- * @version 4.3.0
+ * @version 4.4.1
  */
 
 /**

src/editor/codemirror-setup.js

@@ -59,6 +59,11 @@ const jetBrainsMonoTheme = EditorView.theme({
  * @returns {EditorView} the created editor view
  */
 function createEditor(parentElement, options = {}) {
+  console.log('[createEditor] Called with parentElement:', parentElement?.id, 'dimensions:', parentElement?.clientWidth, 'x', parentElement?.clientHeight);
+  if (!parentElement) {
+    console.error('[createEditor] ERROR: parentElement is null or undefined!');
+    return null;
+  }
   const {
     content = '',
     onChange = () => {},

src/index.html

@@ -2,6 +2,9 @@
 <html lang="en">
 <head>
     <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' 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 -->
@@ -285,6 +288,52 @@
                         </div>
                     </div>
 
+                    <div class="export-section revealjs-only" style="display: none;">
+                        <label>Reveal.js Options:</label>
+                        <div class="form-row">
+                            <label for="reveal-theme">Slide Theme:</label>
+                            <select id="reveal-theme">
+                                <option value="black">Black</option>
+                                <option value="white">White</option>
+                                <option value="league">League</option>
+                                <option value="beige">Beige</option>
+                                <option value="sky">Sky</option>
+                                <option value="night">Night</option>
+                                <option value="serif">Serif</option>
+                                <option value="simple">Simple</option>
+                                <option value="solarized">Solarized</option>
+                                <option value="blood">Blood</option>
+                                <option value="moon">Moon</option>
+                            </select>
+                        </div>
+                        <div class="form-row">
+                            <label for="reveal-transition">Transition:</label>
+                            <select id="reveal-transition">
+                                <option value="slide">Slide</option>
+                                <option value="none">None</option>
+                                <option value="fade">Fade</option>
+                                <option value="convex">Convex</option>
+                                <option value="concave">Concave</option>
+                                <option value="zoom">Zoom</option>
+                            </select>
+                        </div>
+                        <div class="form-row">
+                            <label for="reveal-speed">Transition Speed:</label>
+                            <select id="reveal-speed">
+                                <option value="default">Default</option>
+                                <option value="fast">Fast</option>
+                                <option value="slow">Slow</option>
+                            </select>
+                        </div>
+                        <div class="checkbox-group">
+                            <label><input type="checkbox" id="reveal-slide-number"> Slide Numbers</label>
+                            <label><input type="checkbox" id="reveal-controls" checked> Controls</label>
+                            <label><input type="checkbox" id="reveal-progress" checked> Progress Bar</label>
+                            <label><input type="checkbox" id="reveal-history" checked> Slide History</label>
+                            <label><input type="checkbox" id="reveal-center" checked> Center Content</label>
+                        </div>
+                    </div>
+
                     <div class="export-section">
                         <label>Bibliography:</label>
                         <div class="form-row">
@@ -902,6 +951,7 @@
                     <button class="modal-close" id="pdf-editor-dialog-close" aria-label="Close">&times;</button>
                 </div>
                 <div class="modal-body pdf-editor-body">
+                    <div class="pdf-editor-left-panel">
                     <!-- Merge PDFs Section -->
                     <div id="pdf-merge-section" class="pdf-operation-section hidden">
                         <div class="export-section">
@@ -1284,6 +1334,16 @@
                         </div>
                     </div>
                 </div>
+
+                <!-- Right Panel: Scrollable Visual Page Sidebar -->
+                <div id="pdf-thumbnail-sidebar" class="pdf-editor-right-panel hidden">
+                    <h4>Page Preview &amp; Editor</h4>
+                    <p class="sidebar-help">Select a PDF to view pages, check to delete, click ↻ to rotate, and use ◀ / ▶ to reorder.</p>
+                    <div id="pdf-thumbnail-grid" class="pdf-thumbnail-grid">
+                        <!-- Page thumbnail cards will be rendered here dynamically -->
+                    </div>
+                </div>
+            </div>
                 <div class="modal-footer">
                     <button id="pdf-editor-cancel" class="btn btn-secondary" data-close>Cancel</button>
                     <button id="pdf-editor-process" class="btn btn-primary">Process</button>
@@ -1602,6 +1662,6 @@
     </div>
 
     <script src="utils/ModalManager.js"></script>
-    <script type="module" src="./renderer.js"></script>
+    <script src="renderer.js"></script>
 </body>
 </html>

src/main.js

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

src/main/PDFOperations.js

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

src/preload.js

@@ -9,7 +9,7 @@
  * - All IPC channels are explicitly whitelisted
  * - Prevents XSS from escalating to full system access
  *
- * @version 4.3.0
+ * @version 4.4.1
  */
 
 const { contextBridge, ipcRenderer } = require('electron');
@@ -23,6 +23,7 @@ const ALLOWED_SEND_CHANNELS = [
   'save-recent-files',
   'clear-recent-files',
   'renderer-ready',
+  'select-custom-css',
 
   // Theme
   'get-theme',
@@ -150,6 +151,8 @@ const ALLOWED_RECEIVE_CHANNELS = [
   'get-content-for-save',
   'get-content-for-spreadsheet',
   'recent-files-cleared',
+  'load-custom-css',
+  'clear-custom-css',
 
   // UI toggles
   'toggle-preview',
@@ -234,7 +237,12 @@ const ALLOWED_RECEIVE_CHANNELS = [
   'load-template-menu',
   'toggle-command-palette',
   'toggle-sidebar-panel',
-  'toggle-bottom-panel'
+  'toggle-bottom-panel',
+
+  // File dialog / directory listing
+  'list-directory',
+  'pick-folder',
+  'pick-file'
 ];
 
 /**
@@ -341,7 +349,10 @@ contextBridge.exposeInMainWorld('electronAPI', {
     exists: (filePath) => ipcRenderer.invoke('path-exists', filePath),
     isDirectory: (filePath) => ipcRenderer.invoke('is-directory', filePath),
     copy: (source, destination) => ipcRenderer.invoke('copy-path', { source, destination }),
-    move: (source, destination) => ipcRenderer.invoke('move-path', { source, destination })
+    move: (source, destination) => ipcRenderer.invoke('move-path', { source, destination }),
+    list: (dirPath) => ipcRenderer.invoke('list-directory', dirPath),
+    pickFolder: () => ipcRenderer.invoke('pick-folder'),
+    pickFile: () => ipcRenderer.invoke('pick-file')
   },
 
   // Theme Operations

src/renderer.js

@@ -1,10 +1,20 @@
 /**
  * MarkdownConverter Renderer Process
- * @version 4.3.0
+ * @version 4.4.2
  */
 
-// Electron removed - using tauri-commands.js
+const { ipcRenderer } = require('electron');
-import { file, events, app, exportDoc, git, pdf, dialog } from './tauri-commands.js';
+
+// 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');
@@ -12,7 +22,13 @@ const DOMPurify = createDOMPurify(window);
 const hljs = require('highlight.js');
 const { createEditor } = require('./editor/codemirror-setup');
 const { undo, redo } = require('@codemirror/commands');
-const { ModalManager } = require('./utils/ModalManager');
+// ModalManager is loaded via <script src="utils/ModalManager.js"> in index.html.
+// It already exists in the global scope — re-declaring with let/const causes
+// SyntaxError: "Identifier 'ModalManager' has already been declared".
+if (typeof ModalManager === 'undefined') {
+    const result = require('./utils/ModalManager');
+    ModalManager = result.ModalManager || result;
+}
 // Lazy-loaded modules — defer heavy imports until first use
 let _SidebarManager, _renderTemplatesPanel, _renderExplorerPanel, _renderGitPanel, _renderSnippetsPanel;
 let _ReplPanel, _CommandPalette, _PrintPreview, _createWelcomeContent;
@@ -103,19 +119,24 @@ marked.use({
         start(src) { return src.match(/^:::(note|warning|tip|danger|info)/m)?.index; },
         tokenizer(src) {
             const match = src.match(/^:::(note|warning|tip|danger|info)\s*\n([\s\S]*?)^:::\s*$/m);
-            if (match) {
+            if (match && match.index === 0) {
+                const admonitionType = match[1];
+                const text = match[2].trim();
+                const tokens = [];
+                this.lexer.blockTokens(text, tokens);
                 return {
                     type: 'admonition',
                     raw: match[0],
-                    admonitionType: match[1],
+                    admonitionType,
-                    text: match[2].trim()
+                    text,
+                    tokens
                 };
             }
         },
         renderer(token) {
             const icons = { note: '\u2139', warning: '\u26A0', tip: '\uD83D\uDCA1', danger: '\uD83D\uDD34', info: '\u2139' };
             const icon = icons[token.admonitionType] || '\u2139';
-            const inner = this.parser.parse(token.text);
+            const inner = this.parser.parse(token.tokens || []);
             return `<div class="admonition admonition-${token.admonitionType}">
                 <div class="admonition-title">${icon} ${token.admonitionType.charAt(0).toUpperCase() + token.admonitionType.slice(1)}</div>
                 <div class="admonition-content">${inner}</div>
@@ -132,8 +153,20 @@ function plantumlEncode(text) {
     return '~h' + hex;
 }
 
+// Scopes user custom CSS by prefixing all selectors to protect application UI
+function scopeCSS(cssText, scopeSelector) {
+    if (!cssText) return '';
+    return cssText.replace(/([^\r\n,{}]+)(,(?=[^}]*{)|(?=[^{]*{))/g, (match, selector, separator) => {
+        const trimmed = selector.trim();
+        if (!trimmed || trimmed.startsWith('@') || trimmed.startsWith(':root') || trimmed.startsWith('from') || trimmed.startsWith('to') || /^\d+%$/.test(trimmed)) {
+            return match;
+        }
+        return scopeSelector + ' ' + trimmed + (separator || '');
+    });
+}
+
 // Module-level reference set by DOMContentLoaded after sidebar registration
-let outlinePanelContainer = null;
+const outlinePanelContainer = null;
 
 // Tab Management
 class TabManager {
@@ -148,6 +181,7 @@ class TabManager {
         this.recentFiles = JSON.parse(localStorage.getItem('recentFiles') || '[]');
         this.previewDebounceTimers = new Map(); // Debounce timers per tab
         this.previewDebounceDelay = 300; // 300ms debounce
+        this.previewCache = new Map(); // Performance optimization render cache
 
         // Initialize first tab
         this.tabs.set(1, {
@@ -231,7 +265,7 @@ class TabManager {
             editorView: null,
             findMatches: [],
             currentMatchIndex: -1,
-            type: type,
+            type: type, // 'markdown' or 'pdf'
             // PDF-specific state
             pdfDoc: null,
             pdfCurrentPage: 1,
@@ -244,6 +278,7 @@ class TabManager {
         this.switchToTab(newTabId);
         this.startAutoSave();
         this.updateTabBar();
+        console.log('createNewTab: tab created with type:', type);
     }
 
     createPdfTab(filePath) {
@@ -455,27 +490,7 @@ class TabManager {
         document.querySelector('.editor-container').appendChild(tabContent);
 
         // Initialize CodeMirror editor
-        const editorContainer = document.getElementById(`editor-cm-${tab.id}`);
+        this.ensureEditor(tab);
-        if (editorContainer) {
-            const isDark = document.body.className.includes('dark');
-            tab.editorView = createEditor(editorContainer, {
-                content: tab.content,
-                onChange: (newContent) => {
-                    tab.content = newContent;
-                    tab.isDirty = true;
-                    this.updatePreview(tab.id);
-                    this.updateWordCount();
-                    this.updateTabBar();
-                    if (outlinePanelContainer?._refreshOutline) outlinePanelContainer._refreshOutline();
-                },
-                onUpdate: (view) => {
-                    this.updateCursorPosition(view);
-                    if (outlinePanelContainer?._setActiveHeading) outlinePanelContainer._setActiveHeading(view.state.doc.lineAt(view.state.selection.main.head).number);
-                },
-                isDark,
-                showLineNumbers: this.showLineNumbers,
-            });
-        }
     }
     
     switchToTab(tabId) {
@@ -501,7 +516,7 @@ class TabManager {
 
         // Notify main process about current file for exports
         const tab = this.tabs.get(tabId);
-        const result = await file.write(path, content);
+        ipcRenderer.send('set-current-file', tab?.filePath || null);
 
         // Refresh outline panel for new tab content
         if (outlinePanelContainer?._refreshOutline) outlinePanelContainer._refreshOutline();
@@ -661,6 +676,11 @@ class TabManager {
         const tab = this.tabs.get(tabId);
         if (!tab || tab.type === 'pdf') return;
 
+        // Guard against auto-renders in large file mode
+        if (tab.largeFileMode && !immediate) {
+            return;
+        }
+
         // Clear existing debounce timer for this tab
         if (this.previewDebounceTimers.has(tabId)) {
             clearTimeout(this.previewDebounceTimers.get(tabId));
@@ -679,20 +699,55 @@ class TabManager {
         }, this.previewDebounceDelay));
     }
 
+    _hash(str) {
+        if (!str) return 0;
+        let hash = 0;
+        for (let i = 0; i < str.length; i++) {
+            hash = ((hash << 5) - hash) + str.charCodeAt(i);
+            hash |= 0; // Convert to 32bit integer
+        }
+        return hash;
+    }
+
     _renderPreview(tabId) {
         const tab = this.tabs.get(tabId);
         const preview = document.getElementById(`preview-${tabId}`);
+        console.log('[_renderPreview] tabId:', tabId, 'tab exists:', !!tab, 'preview exists:', !!preview, 'content length:', tab?.content?.length);
 
         if (!tab || !preview) return;
 
         try {
             // Check if libraries are available
             if (!marked || !DOMPurify) {
+                console.error('[_renderPreview] Libraries not available:', { marked: !!marked, DOMPurify: !!DOMPurify });
                 preview.innerHTML = '<div class="preview-error"><div class="preview-error-icon">⚠️</div><div class="preview-error-title">Libraries Not Loaded</div><div class="preview-error-message">Required libraries (marked/DOMPurify) could not be loaded. Please check your installation.</div></div>';
                 return;
             }
-            const html = marked.parse(tab.content);
+
-            let sanitizedHtml = DOMPurify.sanitize(html);
+            // Cache lookup
+            const contentHash = this._hash(tab.content);
+            let sanitizedHtml;
+            if (this.previewCache.has(contentHash)) {
+                console.log('[_renderPreview] Cache hit for hash:', contentHash);
+                sanitizedHtml = this.previewCache.get(contentHash);
+            } else {
+                console.log('[_renderPreview] Cache miss. About to call marked.parse, content length:', tab.content.length);
+                const html = marked.parse(tab.content);
+                console.log('[_renderPreview] marked.parse returned type:', typeof html, 'isPromise:', html instanceof Promise);
+                if (html instanceof Promise) {
+                    console.error('[_renderPreview] marked.parse returned a Promise! Need to await it.');
+                    return;
+                }
+                sanitizedHtml = DOMPurify.sanitize(html);
+                console.log('[_renderPreview] DOMPurify.sanitize returned, length:', sanitizedHtml.length);
+
+                // Add to cache and maintain cache size limit (100 entries)
+                this.previewCache.set(contentHash, sanitizedHtml);
+                if (this.previewCache.size > 100) {
+                    const oldestKey = this.previewCache.keys().next().value;
+                    this.previewCache.delete(oldestKey);
+                }
+            }
 
             // TOC generation
             if (sanitizedHtml.includes('[[toc]]') || sanitizedHtml.includes('[TOC]')) {
@@ -924,7 +979,7 @@ class TabManager {
 
         // Only auto-save if content has changed since last save
         if (tab.lastSavedContent !== tab.content) {
-            await file.write(tab.filePath, tab.content);
+            ipcRenderer.send('save-file', { path: tab.filePath, content: tab.content });
             tab.lastSavedContent = tab.content;
 
             // Show brief auto-save indicator
@@ -963,7 +1018,7 @@ class TabManager {
 
         // Save to localStorage and sync with main process
         localStorage.setItem('recentFiles', JSON.stringify(this.recentFiles));
-        await app.saveRecentFiles(this.recentFiles);
+        ipcRenderer.send('save-recent-files', this.recentFiles);
     }
 
     getRecentFiles() {
@@ -1328,10 +1383,22 @@ class TabManager {
         }
     }
     
+    checkForLargeFile(tab, content) {
+        if (content && content.length > 1024 * 1024) { // >1MB
+            tab.largeFileMode = true;
+            this.isPreviewVisible = false;
+            this.updatePreviewVisibility();
+            notifyUser('Large file detected (>1MB). Large File Mode enabled to maintain peak responsiveness. Live preview auto-render is disabled.', 'warning');
+        } else {
+            tab.largeFileMode = false;
+        }
+    }
+
     // File operations
     openFile(filePath, content) {
         console.log('openFile called with:', filePath, 'content length:', content.length);
         let tab = this.tabs.get(this.activeTabId);
+        console.log('openFile tab state before:', { id: tab?.id, hasEditorView: !!tab?.editorView, contentLength: tab?.content?.length, filePath: tab?.filePath, isDirty: tab?.isDirty });
 
         // Handle both forward and back slashes for cross-platform compatibility
         const fileName = filePath.split(/[\\/]/).pop();
@@ -1345,24 +1412,31 @@ class TabManager {
             tab.originalContent = content;
             tab.isDirty = false;
 
+            this.checkForLargeFile(tab, content);
+
             // Update the editor and preview
             this.setEditorContent(this.activeTabId, content);
-            this.updatePreview(this.activeTabId);
+            console.log('openFile after setEditorContent, tab state:', { id: tab.id, hasEditorView: !!tab.editorView, contentLength: tab.content.length });
+            this.updatePreview(this.activeTabId, true); // immediate=true for initial load
             this.updateWordCount();
         } else {
             // Create new tab for the file
             console.log('Creating new tab for file');
             this.createNewTab();
             tab = this.tabs.get(this.activeTabId);
+            console.log('openFile after createNewTab, tab:', { id: tab.id, hasEditorView: !!tab.editorView });
             tab.filePath = filePath;
             tab.title = fileName;
             tab.content = content;
             tab.originalContent = content;
             tab.isDirty = false;
 
+            this.checkForLargeFile(tab, content);
+
             // Set content in the CodeMirror editor
             this.setEditorContent(this.activeTabId, content);
-            this.updatePreview(this.activeTabId);
+            console.log('openFile after setEditorContent, tab state:', { id: tab.id, hasEditorView: !!tab.editorView, contentLength: tab.content.length });
+            this.updatePreview(this.activeTabId, true); // immediate=true for initial load
             this.updateWordCount();
         }
         this.startAutoSave();
@@ -1370,9 +1444,10 @@ class TabManager {
         this.updateTabBar();
         this.updateFilePath();
         this.updateBreadcrumb();
+        this.updateUI(); // Ensure tab content is visible
 
         // Notify main process about current file for exports
-        // handled via event
+        ipcRenderer.send('set-current-file', filePath);
 
         console.log('File opened successfully');
     }
@@ -1386,9 +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 }
@@ -1446,6 +1559,13 @@ let replPanel;
 
 document.addEventListener('DOMContentLoaded', async () => {
     tabManager = new TabManager();
+
+    // Load saved Custom Preview CSS if present
+    const savedCSSContent = localStorage.getItem('customPreviewCSSContent');
+    if (savedCSSContent) {
+        applyCustomPreviewCSS(savedCSSContent);
+    }
+
     const ReplPanel = getReplPanel();
     replPanel = new ReplPanel();
 
@@ -1484,12 +1604,12 @@ document.addEventListener('DOMContentLoaded', async () => {
     // Initialize sidebar
     const SidebarManager = getSidebarManager();
     const sidebarManager = new SidebarManager();
-    let explorerCurrentDir = null;
+    const explorerCurrentDir = null;
 
     sidebarManager.registerPanel('explorer', {
         title: 'Explorer',
         render: (container) => getRenderExplorerPanel()(container, {
-            listDirectory: (dir) => file.listDirectory(dir),
+            listDirectory: (dir) => ipcRenderer.invoke('list-directory', dir),
             onFileOpen: (filePath) => ipcRenderer.send('open-file-path', filePath),
             currentDir: explorerCurrentDir,
         })
@@ -1497,11 +1617,11 @@ document.addEventListener('DOMContentLoaded', async () => {
     sidebarManager.registerPanel('git', {
         title: 'Git',
         render: (container) => getRenderGitPanel()(container, {
-            gitStatus: () => git.status(tab?.filePath ? path.dirname(tab.filePath) : null),
+            gitStatus: () => ipcRenderer.invoke('git-status'),
-            gitDiff: (file) => git.diff(path.dirname(file) || null, file),
+            gitDiff: (file) => ipcRenderer.invoke('git-diff', { file }),
-            gitStage: (files) => git.stage(path.dirname(files[0]) || null, files),
+            gitStage: (files) => ipcRenderer.invoke('git-stage', { files }),
-            gitCommit: (message) => git.commit(getGitRepoPath(), message),
+            gitCommit: (message) => ipcRenderer.invoke('git-commit', { message }),
-            gitLog: () => git.log(getGitRepoPath()),
+            gitLog: () => ipcRenderer.invoke('git-log'),
         })
     });
     sidebarManager.registerPanel('snippets', {
@@ -1516,7 +1636,7 @@ document.addEventListener('DOMContentLoaded', async () => {
     sidebarManager.registerPanel('templates', {
         title: 'Templates',
         render: (container) => getRenderTemplatesPanel()(container, async (file) => {
-            const templateContent = await ipcRenderer.invoke('load-template', file),
+            const templateContent = await ipcRenderer.invoke('load-template', file);
             if (templateContent) {
                 const content = templateContent.replace(/\{\{DATE\}\}/g, new Date().toISOString().split('T')[0]);
                 tabManager.createNewTab();
@@ -1625,7 +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}`);
@@ -1767,6 +1888,8 @@ document.addEventListener('DOMContentLoaded', async () => {
     commandPalette.register('Insert Image', '', () => tabManager.wrapSelection('![', '](image.jpg)'));
     commandPalette.register('Toggle Zen Mode', 'F11', () => zenMode.toggle());
     commandPalette.register('Writing Analytics', 'Ctrl+Shift+A', () => getShowAnalyticsModal()(tabManager));
+    commandPalette.register('Load Custom Preview CSS', '', triggerLoadCustomCSS);
+    commandPalette.register('Clear Custom Preview CSS', '', triggerClearCustomCSS);
 
     // Keyboard shortcuts
     document.addEventListener('keydown', (e) => {
@@ -1792,27 +1915,9 @@ document.addEventListener('DOMContentLoaded', async () => {
     });
 
     // Initialize CodeMirror for the initial tab (tab 1)
-    const initialEditorContainer = document.getElementById('editor-cm-1');
+    const initialTab = tabManager.tabs.get(1);
-    if (initialEditorContainer) {
+    if (initialTab) {
-        const tab = tabManager.tabs.get(1);
+        tabManager.ensureEditor(initialTab);
-        const isDark = document.body.className.includes('dark');
-        tab.editorView = createEditor(initialEditorContainer, {
-            content: tab.content,
-            onChange: (newContent) => {
-                tab.content = newContent;
-                tab.isDirty = true;
-                tabManager.updatePreview(tab.id);
-                tabManager.updateWordCount();
-                tabManager.updateTabBar();
-                if (outlinePanelContainer?._refreshOutline) outlinePanelContainer._refreshOutline();
-            },
-            onUpdate: (view) => {
-                tabManager.updateCursorPosition(view);
-                if (outlinePanelContainer?._setActiveHeading) outlinePanelContainer._setActiveHeading(view.state.doc.lineAt(view.state.selection.main.head).number);
-            },
-            isDark,
-            showLineNumbers: tabManager.showLineNumbers,
-        });
     }
 
     // Request current theme
@@ -1837,20 +1942,33 @@ document.addEventListener('DOMContentLoaded', async () => {
 });
 
 // IPC event listeners
-events.onFileNew(() => {
+// IPC event listeners
+ipcRenderer.on('file-new', () => {
     tabManager.createNewTab();
 });
 
-events.onFileOpened((event, data) => {
+ipcRenderer.on('file-opened', (event, data) => {
     console.log('[RENDERER] file-opened received:', data.path, 'content length:', data.content.length);
+    console.log('[RENDERER] activeTabId before openFile:', tabManager.activeTabId);
+    // Diagnostic: check library state
+    console.log('[RENDERER] Library state:', {
+        marked: typeof marked,
+        DOMPurify: typeof DOMPurify,
+        markedParse: typeof marked?.parse,
+        dompurifySanitize: typeof DOMPurify?.sanitize,
+        tabManagerExists: !!tabManager
+    });
     if (tabManager) {
         tabManager.openFile(data.path, data.content);
+        console.log('[RENDERER] activeTabId after openFile:', tabManager.activeTabId);
+        const tab = tabManager.tabs.get(tabManager.activeTabId);
+        console.log('[RENDERER] tab state:', { id: tab?.id, hasEditorView: !!tab?.editorView, contentLength: tab?.content?.length });
     } else {
         console.error('[RENDERER] tabManager not initialized!');
     }
 });
 
-events.onFileSave(() => {
+ipcRenderer.on('file-save', () => {
     const currentContent = tabManager.getCurrentContent();
     const currentFilePath = tabManager.getCurrentFilePath();
     // send to main process which will save or trigger save-as dialog
@@ -1878,12 +1996,12 @@ ipcRenderer.on('get-content-for-spreadsheet', (event, format) => {
     ipcRenderer.send('export-spreadsheet', { content: currentContent, format });
 });
 
-events.onTogglePreview(() => {
+ipcRenderer.on('toggle-preview', () => {
     tabManager.isPreviewVisible = !tabManager.isPreviewVisible;
     tabManager.updatePreviewVisibility();
 });
 
-events.onToggleFind(() => {
+ipcRenderer.on('toggle-find', () => {
     if (window.modals.findModal.isOpen()) {
         window.modals.findModal.close();
     } else {
@@ -1892,7 +2010,7 @@ events.onToggleFind(() => {
     }
 });
 
-events.onThemeChanged((event, theme) => {
+ipcRenderer.on('theme-changed', (event, theme) => {
     console.log('[RENDERER] Theme changed to:', theme);
     document.body.className = `theme-${theme}`;
 
@@ -1905,7 +2023,7 @@ events.onThemeChanged((event, theme) => {
 });
 
 // Undo/Redo handlers — delegate to CodeMirror's built-in history
-events.onUndo(() => {
+ipcRenderer.on('undo', () => {
     if (tabManager) {
         const tab = tabManager.tabs.get(tabManager.activeTabId);
         if (tab?.editorView) {
@@ -1914,7 +2032,7 @@ events.onUndo(() => {
     }
 });
 
-events.onRedo(() => {
+ipcRenderer.on('redo', () => {
     if (tabManager) {
         const tab = tabManager.tabs.get(tabManager.activeTabId);
         if (tab?.editorView) {
@@ -1923,6 +2041,49 @@ events.onRedo(() => {
     }
 });
 
+// Custom Preview CSS event handlers and trigger helpers
+function applyCustomPreviewCSS(cssContent) {
+    let styleTag = document.getElementById('custom-preview-style');
+    if (!styleTag) {
+        styleTag = document.createElement('style');
+        styleTag.id = 'custom-preview-style';
+        document.head.appendChild(styleTag);
+    }
+    const scopedCSS = scopeCSS(cssContent, '.preview-content');
+    styleTag.textContent = scopedCSS;
+}
+
+async function triggerLoadCustomCSS() {
+    try {
+        const result = await window.electronAPI.invoke('select-custom-css');
+        if (result) {
+            console.log('[RENDERER] Custom CSS loaded from:', result.path);
+            localStorage.setItem('customPreviewCSSPath', result.path);
+            localStorage.setItem('customPreviewCSSContent', result.content);
+            applyCustomPreviewCSS(result.content);
+            notifyUser('Custom preview stylesheet applied successfully.', 'success');
+        }
+    } catch (err) {
+        console.error('[RENDERER] Error loading custom CSS:', err);
+        notifyUser('Failed to load custom CSS stylesheet.', 'error');
+    }
+}
+
+function triggerClearCustomCSS() {
+    localStorage.removeItem('customPreviewCSSPath');
+    localStorage.removeItem('customPreviewCSSContent');
+    const styleTag = document.getElementById('custom-preview-style');
+    if (styleTag) {
+        styleTag.remove();
+    }
+    notifyUser('Custom preview stylesheet cleared.', 'info');
+}
+
+ipcRenderer.on('load-custom-css', triggerLoadCustomCSS);
+ipcRenderer.on('clear-custom-css', triggerClearCustomCSS);
+
+
+
 // Font size adjustment
 let currentFontSize = parseInt(localStorage.getItem('fontSize')) || 15;
 
@@ -2042,13 +2203,39 @@ function initializeExportForm(format) {
     document.getElementById('export-citeproc').checked = false;
     document.getElementById('export-toc-depth').value = 3;
 
-    // PDF-specific fields
+    // Toggle and reset PDF-specific fields
+    const pdfOnly = document.querySelector('.pdf-only');
+    if (pdfOnly) {
+        pdfOnly.style.display = (format === 'pdf') ? 'block' : 'none';
+    }
     if (format === 'pdf') {
         document.getElementById('pdf-engine').value = 'xelatex';
         document.getElementById('pdf-geometry').value = 'margin=1in';
         document.getElementById('custom-geometry').style.display = 'none';
     }
 
+    // Toggle and reset Reveal.js-specific fields
+    const revealjsOnly = document.querySelector('.revealjs-only');
+    if (revealjsOnly) {
+        revealjsOnly.style.display = (format === 'revealjs') ? 'block' : 'none';
+    }
+    const revealTheme = document.getElementById('reveal-theme');
+    if (revealTheme) revealTheme.value = 'black';
+    const revealTransition = document.getElementById('reveal-transition');
+    if (revealTransition) revealTransition.value = 'slide';
+    const revealSpeed = document.getElementById('reveal-speed');
+    if (revealSpeed) revealSpeed.value = 'default';
+    const revealSlideNumber = document.getElementById('reveal-slide-number');
+    if (revealSlideNumber) revealSlideNumber.checked = false;
+    const revealControls = document.getElementById('reveal-controls');
+    if (revealControls) revealControls.checked = true;
+    const revealProgress = document.getElementById('reveal-progress');
+    if (revealProgress) revealProgress.checked = true;
+    const revealHistory = document.getElementById('reveal-history');
+    if (revealHistory) revealHistory.checked = true;
+    const revealCenter = document.getElementById('reveal-center');
+    if (revealCenter) revealCenter.checked = true;
+
     // Clear bibliography fields
     document.getElementById('bibliography-file').value = '';
     document.getElementById('csl-file').value = '';
@@ -2108,6 +2295,18 @@ function collectExportOptions() {
             }
         }
 
+        // Reveal.js-specific options
+        if (currentExportFormat === 'revealjs') {
+            options.revealTheme = document.getElementById('reveal-theme').value;
+            options.revealTransition = document.getElementById('reveal-transition').value;
+            options.revealTransitionSpeed = document.getElementById('reveal-speed').value;
+            options.revealSlideNumber = document.getElementById('reveal-slide-number').checked;
+            options.revealControls = document.getElementById('reveal-controls').checked;
+            options.revealProgress = document.getElementById('reveal-progress').checked;
+            options.revealHistory = document.getElementById('reveal-history').checked;
+            options.revealCenter = document.getElementById('reveal-center').checked;
+        }
+
         // Bibliography
         const bibFile = document.getElementById('bibliography-file').value.trim();
         const cslFile = document.getElementById('csl-file').value.trim();
@@ -2118,6 +2317,15 @@ function collectExportOptions() {
         if (currentExportFormat === 'pdf') {
             options.pdfEngine = 'xelatex';
             options.geometry = 'margin=1in';
+        } else if (currentExportFormat === 'revealjs') {
+            options.revealTheme = 'black';
+            options.revealTransition = 'slide';
+            options.revealTransitionSpeed = 'default';
+            options.revealSlideNumber = false;
+            options.revealControls = true;
+            options.revealProgress = true;
+            options.revealHistory = true;
+            options.revealCenter = true;
         }
     }
 
@@ -3035,6 +3243,18 @@ function showPDFEditorDialog(operation, openedFilePath = null) {
         section.classList.add('hidden');
     });
 
+    // Hide visual thumbnail sidebar by default
+    const sidebar = document.getElementById('pdf-thumbnail-sidebar');
+    if (sidebar) {
+        sidebar.classList.add('hidden');
+    }
+    const body = document.querySelector('.pdf-editor-body');
+    if (body) {
+        body.classList.remove('side-by-side');
+    }
+    pdfDocInstance = null;
+    pdfPreviewState = { pages: [], filePath: '' };
+
     // Show the appropriate section and set title
     let sectionId, titleText;
     switch (operation) {
@@ -3068,7 +3288,11 @@ function showPDFEditorDialog(operation, openedFilePath = null) {
             titleText = 'Rotate Pages';
             if (openedFilePath) {
                 const rotateInput = document.getElementById('rotate-input-path');
-                if (rotateInput) rotateInput.value = openedFilePath;
+                if (rotateInput) {
+                    rotateInput.value = openedFilePath;
+                    // Trigger thumbnail generation
+                    setTimeout(() => onPDFFileSelected('rotate-input-path', openedFilePath), 50);
+                }
             }
             break;
         case 'delete':
@@ -3076,7 +3300,11 @@ function showPDFEditorDialog(operation, openedFilePath = null) {
             titleText = 'Delete Pages';
             if (openedFilePath) {
                 const deleteInput = document.getElementById('delete-input-path');
-                if (deleteInput) deleteInput.value = openedFilePath;
+                if (deleteInput) {
+                    deleteInput.value = openedFilePath;
+                    // Trigger thumbnail generation
+                    setTimeout(() => onPDFFileSelected('delete-input-path', openedFilePath), 50);
+                }
             }
             break;
         case 'reorder':
@@ -3084,7 +3312,11 @@ function showPDFEditorDialog(operation, openedFilePath = null) {
             titleText = 'Reorder Pages';
             if (openedFilePath) {
                 const reorderInput = document.getElementById('reorder-input-path');
-                if (reorderInput) reorderInput.value = openedFilePath;
+                if (reorderInput) {
+                    reorderInput.value = openedFilePath;
+                    // Trigger thumbnail generation
+                    setTimeout(() => onPDFFileSelected('reorder-input-path', openedFilePath), 50);
+                }
             }
             break;
         case 'watermark':
@@ -3245,6 +3477,7 @@ document.addEventListener('DOMContentLoaded', () => {
                         const file = e.target.files[0];
                         if (file) {
                             document.getElementById(button.inputId).value = file.path;
+                            onPDFFileSelected(button.inputId, file.path);
                         }
                     };
                     input.click();
@@ -3254,6 +3487,7 @@ document.addEventListener('DOMContentLoaded', () => {
                         const file = e.target.files[0];
                         if (file) {
                             document.getElementById(button.inputId).value = file.path;
+                            onPDFFileSelected(button.inputId, file.path);
                         }
                     };
                     input.click();
@@ -3398,7 +3632,7 @@ function showPDFValidationMessage(message, focusSelector = null) {
 // Process PDF Operation
 function processPDFOperation() {
     const operation = currentPDFOperation;
-    let operationData = { operation };
+    const operationData = { operation };
 
     try {
         switch (operation) {
@@ -4188,7 +4422,7 @@ function textToASCII(text, style) {
         lines[i] = '';
     }
 
-    for (let char of upperText) {
+    for (const char of upperText) {
         const charLines = font.chars[char] || font.chars[' '];
         if (charLines) {
             for (let i = 0; i < font.height; i++) {
@@ -4226,7 +4460,7 @@ function createASCIIBox(text, style, padding) {
     }
 
     // Content lines
-    for (let line of lines) {
+    for (const line of lines) {
         const paddedLine = line.padEnd(maxLength, ' ');
         result += chars.v + ' '.repeat(padding) + paddedLine + ' '.repeat(padding) + chars.v + '\n';
     }
@@ -4862,3 +5096,224 @@ ipcRenderer.on('show-video-tool', (event, tool) => {
         { duration: 5000 }
     );
 });
+
+// ============================================
+// PDF EDITOR VISUAL PAGE SIDEBAR HANDLERS
+// ============================================
+let pdfDocInstance = null;
+let pdfPreviewState = { pages: [], filePath: '' };
+
+function onPDFFileSelected(inputId, filePath) {
+    const eligibleInputs = ['rotate-input-path', 'delete-input-path', 'reorder-input-path'];
+    if (!eligibleInputs.includes(inputId)) {
+        return;
+    }
+
+    const sidebar = document.getElementById('pdf-thumbnail-sidebar');
+    if (sidebar) {
+        sidebar.classList.remove('hidden');
+    }
+    const body = document.querySelector('.pdf-editor-body');
+    if (body) {
+        body.classList.add('side-by-side');
+    }
+
+    loadPDFThumbnails(filePath);
+}
+
+async function loadPDFThumbnails(filePath) {
+    const grid = document.getElementById('pdf-thumbnail-grid');
+    if (!grid) return;
+
+    // Reset previous inputs
+    const rotateInput = document.getElementById('rotate-pages');
+    if (rotateInput) rotateInput.value = '';
+    const deleteInput = document.getElementById('delete-pages');
+    if (deleteInput) deleteInput.value = '';
+    const reorderInput = document.getElementById('reorder-pages');
+    if (reorderInput) reorderInput.value = '';
+
+    grid.innerHTML = '<div class="loading-thumbnails">Loading page thumbnails...</div>';
+
+    try {
+        const pdfjs = getPdfjsLib();
+        const loadingTask = pdfjs.getDocument(filePath);
+        pdfDocInstance = await loadingTask.promise;
+
+        pdfPreviewState.filePath = filePath;
+        pdfPreviewState.pages = [];
+
+        for (let i = 1; i <= pdfDocInstance.numPages; i++) {
+            pdfPreviewState.pages.push({
+                originalPageNum: i,
+                rotation: 0,
+                isDeleted: false
+            });
+        }
+
+        renderThumbnailGrid();
+    } catch (err) {
+        console.error('Error loading PDF thumbnails:', err);
+        grid.innerHTML = '<div class="thumbnail-error">Failed to load PDF thumbnails.</div>';
+    }
+}
+
+function renderThumbnailGrid() {
+    const grid = document.getElementById('pdf-thumbnail-grid');
+    if (!grid || !pdfDocInstance) return;
+
+    grid.innerHTML = '';
+
+    pdfPreviewState.pages.forEach((pageInfo, index) => {
+        const card = document.createElement('div');
+        card.className = 'pdf-thumbnail-card';
+        if (pageInfo.isDeleted) {
+            card.classList.add('marked-delete');
+        }
+
+        const heading = document.createElement('div');
+        heading.className = 'pdf-thumbnail-header';
+        heading.innerHTML = `<span class="badge">Page ${pageInfo.originalPageNum}</span>`;
+
+        const canvasContainer = document.createElement('div');
+        canvasContainer.className = 'canvas-container';
+
+        const canvas = document.createElement('canvas');
+        canvas.className = 'pdf-thumbnail-canvas';
+        if (pageInfo.rotation > 0) {
+            canvas.classList.add('rot' + pageInfo.rotation);
+        }
+        canvasContainer.appendChild(canvas);
+
+        // Render thumbnail canvas
+        renderThumbnail(pdfDocInstance, pageInfo.originalPageNum, canvas, pageInfo.rotation);
+
+        const controlsRow = document.createElement('div');
+        controlsRow.className = 'pdf-thumbnail-controls';
+
+        // Rotate Button
+        const rotateBtn = document.createElement('button');
+        rotateBtn.type = 'button';
+        rotateBtn.className = 'btn-rotate-thumbnail';
+        rotateBtn.innerHTML = '↻ Rotate 90°';
+        rotateBtn.addEventListener('click', () => {
+            pageInfo.rotation = (pageInfo.rotation + 90) % 360;
+            canvas.className = 'pdf-thumbnail-canvas';
+            if (pageInfo.rotation > 0) {
+                canvas.classList.add('rot' + pageInfo.rotation);
+            }
+            renderThumbnail(pdfDocInstance, pageInfo.originalPageNum, canvas, pageInfo.rotation);
+            syncRotateInput();
+        });
+
+        // Delete Checkbox
+        const deleteLabel = document.createElement('label');
+        deleteLabel.className = 'delete-thumbnail-checkbox';
+
+        const deleteChk = document.createElement('input');
+        deleteChk.type = 'checkbox';
+        deleteChk.checked = pageInfo.isDeleted;
+        deleteChk.addEventListener('change', (e) => {
+            pageInfo.isDeleted = e.target.checked;
+            card.classList.toggle('marked-delete', pageInfo.isDeleted);
+            syncDeleteInput();
+        });
+        deleteLabel.appendChild(deleteChk);
+        deleteLabel.appendChild(document.createTextNode(' Delete'));
+
+        // Reorder buttons
+        const reorderDiv = document.createElement('div');
+        reorderDiv.className = 'pdf-thumbnail-reorder';
+
+        const leftBtn = document.createElement('button');
+        leftBtn.type = 'button';
+        leftBtn.className = 'btn-reorder-left';
+        leftBtn.innerHTML = '◀';
+        leftBtn.disabled = (index === 0);
+        leftBtn.addEventListener('click', () => {
+            const temp = pdfPreviewState.pages[index];
+            pdfPreviewState.pages[index] = pdfPreviewState.pages[index - 1];
+            pdfPreviewState.pages[index - 1] = temp;
+            renderThumbnailGrid();
+            syncReorderInput();
+        });
+
+        const rightBtn = document.createElement('button');
+        rightBtn.type = 'button';
+        rightBtn.className = 'btn-reorder-right';
+        rightBtn.innerHTML = '▶';
+        rightBtn.disabled = (index === pdfPreviewState.pages.length - 1);
+        rightBtn.addEventListener('click', () => {
+            const temp = pdfPreviewState.pages[index];
+            pdfPreviewState.pages[index] = pdfPreviewState.pages[index + 1];
+            pdfPreviewState.pages[index + 1] = temp;
+            renderThumbnailGrid();
+            syncReorderInput();
+        });
+
+        reorderDiv.appendChild(leftBtn);
+        reorderDiv.appendChild(rightBtn);
+
+        controlsRow.appendChild(rotateBtn);
+        controlsRow.appendChild(deleteLabel);
+        controlsRow.appendChild(reorderDiv);
+
+        card.appendChild(heading);
+        card.appendChild(canvasContainer);
+        card.appendChild(controlsRow);
+
+        grid.appendChild(card);
+    });
+}
+
+async function renderThumbnail(pdfDoc, originalPageNum, canvasElement, rotation) {
+    try {
+        const page = await pdfDoc.getPage(originalPageNum);
+        const ctx = canvasElement.getContext('2d');
+
+        // Render at a fixed width of 100px
+        const unscaledViewport = page.getViewport({ scale: 1, rotation: 0 });
+        const scale = 100 / unscaledViewport.width;
+        const viewport = page.getViewport({ scale: scale, rotation: 0 });
+
+        canvasElement.width = viewport.width;
+        canvasElement.height = viewport.height;
+
+        await page.render({
+            canvasContext: ctx,
+            viewport: viewport
+        }).promise;
+    } catch (err) {
+        console.error('Error rendering page canvas:', err);
+    }
+}
+
+function syncRotateInput() {
+    const rotatedPages = pdfPreviewState.pages
+        .filter(p => p.rotation > 0)
+        .map(p => p.originalPageNum);
+
+    const rotateInput = document.getElementById('rotate-pages');
+    if (rotateInput) {
+        rotateInput.value = rotatedPages.join(', ');
+    }
+}
+
+function syncDeleteInput() {
+    const deletedPages = pdfPreviewState.pages
+        .filter(p => p.isDeleted)
+        .map(p => p.originalPageNum);
+
+    const deleteInput = document.getElementById('delete-pages');
+    if (deleteInput) {
+        deleteInput.value = deletedPages.join(', ');
+    }
+}
+
+function syncReorderInput() {
+    const order = pdfPreviewState.pages.map(p => p.originalPageNum);
+    const reorderInput = document.getElementById('reorder-pages');
+    if (reorderInput) {
+        reorderInput.value = order.join(', ');
+    }
+}

src/renderer/App.tsx

@@ -0,0 +1,7 @@
+import { AppShell } from './components/layout/AppShell';
+
+function App() {
+  return <AppShell />;
+}
+
+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 +1,41 @@
+import { PanelLeft, PanelRight } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+import { ThemeToggle } from '@/components/theme-toggle';
+import { useAppStore } from '@/stores/app-store';
+
+export function AppHeader() {
+  const { sidebarVisible, previewVisible, toggleSidebar, togglePreview } = useAppStore();
+
+  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}
+          onClick={toggleSidebar}
+        >
+          <PanelLeft className="h-4 w-4" />
+        </Button>
+        <Button
+          variant="ghost"
+          size="icon"
+          aria-label="Toggle preview"
+          aria-pressed={previewVisible}
+          onClick={togglePreview}
+        >
+          <PanelRight className="h-4 w-4" />
+        </Button>
+        <ThemeToggle />
+      </div>
+    </header>
+  );
+}

src/renderer/components/layout/AppShell.tsx

@@ -0,0 +1,56 @@
+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';
+
+export function AppShell() {
+  useFileShortcuts();
+  useRestoreLastFolder();
+  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 +1,15 @@
+import { Bold, Italic, List, ListOrdered, Code, Link as LinkIcon } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+
+export function Toolbar() {
+  return (
+    <div className="flex h-10 items-center gap-1 border-b border-border bg-card/10 px-3">
+      <Button variant="ghost" size="icon" aria-label="Bold"><Bold className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Italic"><Italic className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Unordered list"><List className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Ordered list"><ListOrdered className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Code"><Code className="h-4 w-4" /></Button>
+      <Button variant="ghost" size="icon" aria-label="Link"><LinkIcon className="h-4 w-4" /></Button>
+    </div>
+  );
+}

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/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/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/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-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/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/ipc.ts

@@ -0,0 +1,98 @@
+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),
+  },
+};

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/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 +1,35 @@
+import { create } from 'zustand';
+import { persist } from 'zustand/middleware';
+
+export interface PaneSizes {
+  sidebar: number;
+  editor: number;
+  preview: number;
+}
+
+interface AppState {
+  sidebarVisible: boolean;
+  previewVisible: boolean;
+  zenMode: boolean;
+  paneSizes: PaneSizes;
+  toggleSidebar: () => void;
+  togglePreview: () => void;
+  setZenMode: (value: boolean) => void;
+  setPaneSizes: (sizes: PaneSizes) => void;
+}
+
+export const useAppStore = create<AppState>()(
+  persist(
+    (set) => ({
+      sidebarVisible: true,
+      previewVisible: true,
+      zenMode: false,
+      paneSizes: { sidebar: 20, editor: 50, preview: 30 },
+      toggleSidebar: () => set((s) => ({ sidebarVisible: !s.sidebarVisible })),
+      togglePreview: () => set((s) => ({ previewVisible: !s.previewVisible })),
+      setZenMode: (value) => set({ zenMode: value }),
+      setPaneSizes: (sizes) => set({ paneSizes: sizes }),
+    }),
+    { name: 'mc-app-store' }
+  )
+);

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/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 +1,35 @@
+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 });
+}

src/renderer/types/electron.d.ts

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

src/renderer/types/ipc.ts

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

src/styles-modern.css

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

src/tauri-commands.js

@@ -1,96 +0,0 @@
-// Tauri Commands Bridge for MarkdownConverter
-// Replaces preload.js — uses Tauri's invoke() instead of ipcRenderer
-
-const { invoke } = window.__TAURI__.core;
-const { listen } = window.__TAURI__.event;
-
-// ============================================
-// FILE OPERATIONS
-// ============================================
-export const file = {
-  read: (path) => invoke('read_file', { path }),
-  write: (path, content) => invoke('write_file', { path, content }),
-  delete: (path) => invoke('delete_file', { path }),
-  exists: (path) => invoke('path_exists', { path }),
-  isDirectory: (path) => invoke('is_directory', { path }),
-  listDirectory: (path) => invoke('list_directory', { path }),
-  ensureDir: (path) => invoke('ensure_directory', { path }),
-  copy: (source, destination) => invoke('copy_path', { source, destination }),
-  move: (source, destination) => invoke('move_path', { source, destination }),
-};
-
-// ============================================
-// EXPORT OPERATIONS
-// ============================================
-export const exportDoc = {
-  markdown: (inputPath, outputPath, format, options) =>
-    invoke('export_markdown', { inputPath, outputPath, format, options }),
-  checkPandoc: () => invoke('check_pandoc_available', {}),
-};
-
-// ============================================
-// GIT OPERATIONS
-// ============================================
-export const git = {
-  status: (repoPath) => invoke('git_status', { repoPath }),
-  stage: (repoPath, path) => invoke('git_stage', { repoPath, path }),
-  commit: (repoPath, message) => invoke('git_commit', { repoPath, message }),
-  log: (repoPath, limit) => invoke('git_log', { repoPath, limit }),
-  diff: (repoPath, path) => invoke('git_diff', { repoPath, path }),
-};
-
-// ============================================
-// APP OPERATIONS
-// ============================================
-export const app = {
-  getVersion: () => invoke('get_app_version'),
-  getRecentFiles: () => invoke('get_recent_files'),
-  saveRecentFiles: (files) => invoke('save_recent_files', { files }),
-};
-
-// ============================================
-// PDF OPERATIONS
-// ============================================
-export const pdf = {
-  getPageCount: (path) => invoke('get_pdf_page_count', { path }),
-  merge: (paths, output) => invoke('merge_pdfs', { paths, output }),
-  split: (input, outputDir, pagesPerSplit) => invoke('split_pdf', { input, outputDir, pagesPerSplit }),
-  rotate: (input, output, degrees) => invoke('rotate_pdf', { input, output, degrees }),
-  deletePages: (input, output, pages) => invoke('delete_pdf_pages', { input, output, pages }),
-};
-
-// ============================================
-// DIALOG OPERATIONS
-// ============================================
-export const dialog = {
-  openFile: () => invoke('open_file_dialog', {}),
-  saveFile: (defaultName) => invoke('save_file_dialog', { defaultName }),
-  selectFolder: () => invoke('select_folder_dialog', {}),
-};
-
-// ============================================
-// EVENT LISTENERS
-// ============================================
-export const events = {
-  onFileNew: (callback) => listen('file-new', callback),
-  onFileOpened: (callback) => listen('file-opened', callback),
-  onFileSave: (callback) => listen('file-save', callback),
-  onTogglePreview: (callback) => listen('toggle-preview', callback),
-  onToggleFind: (callback) => listen('toggle-find', callback),
-  onUndo: (callback) => listen('undo', callback),
-  onRedo: (callback) => listen('redo', callback),
-  onThemeChanged: (callback) => listen('theme-changed', callback),
-  onToggleCommandPalette: (callback) => listen('toggle-command-palette', callback),
-  onToggleSidebarPanel: (callback) => listen('toggle-sidebar-panel', callback),
-  onToggleBottomPanel: (callback) => listen('toggle-bottom-panel', callback),
-  onConversionComplete: (callback) => listen('conversion-complete', callback),
-  onConversionStatus: (callback) => listen('conversion-status', callback),
-};
-
-// ============================================
-// PLUGIN OPERATIONS
-// ============================================
-export const plugins = {
-  list: () => invoke('list_plugins', {}),
-  get: (name) => invoke('get_plugin', { name }),
-};

src/utils/ModalManager.js

@@ -1,6 +1,6 @@
 /**
  * ModalManager - Unified modal system with accessibility support
- * @version 4.3.0
+ * @version 4.4.2
  */
 class ModalManager {
     #modal;
@@ -237,8 +237,8 @@ class ModalManager {
     }
 }
 
-// Export for use in renderer
+// Export for use in renderer - avoid duplicate declaration
-if (typeof window !== 'undefined') {
+if (typeof window !== 'undefined' && !window.ModalManager) {
     window.ModalManager = ModalManager;
 }
 

src/vite.config.js

@@ -1,15 +0,0 @@
-import { defineConfig } from 'vite';
-
-export default defineConfig({
-  root: '.',
-  base: './',
-  build: {
-    outDir: '../dist',
-    emptyOutDir: true,
-  },
-  server: {
-    port: 1420,
-    strictPort: true,
-  },
-  clearScreen: false,
-});

src/wordTemplateExporter.js

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

src/zen-mode.js

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

tailwind.config.js

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

tests/component/editor/EditorPane.test.tsx

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

tests/component/layout/AppHeader.test.tsx

@@ -0,0 +1,33 @@
+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';
+
+describe('AppHeader', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    useAppStore.setState({ sidebarVisible: true, previewVisible: true, zenMode: false });
+  });
+
+  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);
+  });
+});

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 +1,11 @@
+import { describe, it, expect } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { Toolbar } from '@/components/layout/Toolbar';
+
+describe('Toolbar', () => {
+  it('renders formatting buttons', () => {
+    render(<Toolbar />);
+    expect(screen.getByRole('button', { name: /bold/i })).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: /italic/i })).toBeInTheDocument();
+  });
+});

tests/component/preview/MermaidLazy.test.tsx

@@ -0,0 +1,28 @@
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen, waitFor } from '@testing-library/react';
+import { MermaidLazy } from '@/components/preview/MermaidLazy';
+
+vi.mock('mermaid', () => ({
+  default: {
+    initialize: vi.fn(),
+    render: vi.fn().mockResolvedValue('<svg></svg>'),
+  },
+}));
+
+describe('MermaidLazy', () => {
+  it('renders an svg after mermaid resolves', async () => {
+    render(<MermaidLazy code="graph TD; A-->B" />);
+    await waitFor(() => {
+      expect(screen.getByTestId('mermaid-output').innerHTML).toContain('<svg');
+    });
+  });
+
+  it('shows an error message if mermaid throws', async () => {
+    const mermaid = (await import('mermaid')).default as any;
+    mermaid.render.mockRejectedValueOnce(new Error('mermaid failed'));
+    render(<MermaidLazy code="bad code" />);
+    await waitFor(() => {
+      expect(screen.getByText(/mermaid failed/i)).toBeInTheDocument();
+    });
+  });
+});

tests/component/preview/PreviewPane.test.tsx

@@ -0,0 +1,30 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { ThemeProvider } from '@/components/theme-provider';
+import { PreviewPane } from '@/components/preview/PreviewPane';
+import { usePreviewStore } from '@/stores/preview-store';
+
+describe('PreviewPane', () => {
+  beforeEach(() => {
+    usePreviewStore.setState({ scrollRatio: 0, source: '' });
+  });
+
+  it('renders empty state when no source', () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <PreviewPane />
+      </ThemeProvider>
+    );
+    expect(screen.getByText(/nothing to preview/i)).toBeInTheDocument();
+  });
+
+  it('renders markdown when source is set', () => {
+    usePreviewStore.setState({ source: '# Hello' });
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <PreviewPane />
+      </ThemeProvider>
+    );
+    expect(screen.getByRole('heading', { level: 1, name: /hello/i })).toBeInTheDocument();
+  });
+});

tests/component/sidebar/FileTree.test.tsx

@@ -0,0 +1,111 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { ThemeProvider } from '@/components/theme-provider';
+import { FileTree } from '@/components/sidebar/FileTree';
+import { useFileStore } from '@/stores/file-store';
+
+vi.mock('@/lib/ipc', () => ({
+  ipc: {
+    file: {
+      list: vi.fn().mockResolvedValue({ ok: true, data: [] }),
+      read: vi.fn().mockResolvedValue({ ok: true, data: '' }),
+    },
+  },
+}));
+
+describe('FileTree', () => {
+  beforeEach(() => {
+    useFileStore.setState({ tree: null, rootPath: null, expanded: new Set(), openTabs: [], activeTabId: null });
+  });
+
+  it('renders nothing when tree is null', () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <FileTree />
+      </ThemeProvider>
+    );
+    expect(screen.queryByRole('button')).toBeNull();
+  });
+
+  it('renders root children after openFolder', async () => {
+    useFileStore.setState({
+      tree: {
+        name: 'project',
+        path: '/project',
+        isDirectory: true,
+        loaded: true,
+        children: [
+          { name: 'src', path: '/project/src', isDirectory: true, children: null, loaded: false },
+          { name: 'README.md', path: '/project/README.md', isDirectory: false, children: null },
+        ],
+      },
+      rootPath: '/project',
+    });
+
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <FileTree />
+      </ThemeProvider>
+    );
+
+    expect(screen.getByText('src')).toBeInTheDocument();
+    expect(screen.getByText('README.md')).toBeInTheDocument();
+  });
+
+  it('shows folder as expanded after toggle and reveals children', async () => {
+    useFileStore.setState({
+      tree: {
+        name: 'project',
+        path: '/project',
+        isDirectory: true,
+        loaded: true,
+        children: [
+          {
+            name: 'src',
+            path: '/project/src',
+            isDirectory: true,
+            loaded: true,
+            children: [
+              { name: 'index.ts', path: '/project/src/index.ts', isDirectory: false, children: null },
+            ],
+          },
+        ],
+      },
+      rootPath: '/project',
+      expanded: new Set(['/project/src']),
+    });
+
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <FileTree />
+      </ThemeProvider>
+    );
+
+    expect(screen.getByText('index.ts')).toBeInTheDocument();
+  });
+
+  it('highlights the active tab path', () => {
+    useFileStore.setState({
+      tree: {
+        name: 'project',
+        path: '/project',
+        isDirectory: true,
+        loaded: true,
+        children: [
+          { name: 'README.md', path: '/project/README.md', isDirectory: false, children: null },
+        ],
+      },
+      rootPath: '/project',
+      activeTabId: '/project/README.md',
+    });
+
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <FileTree />
+      </ThemeProvider>
+    );
+
+    const btn = screen.getByRole('button', { name: /README.md/i });
+    expect(btn).toHaveClass('bg-accent');
+  });
+});

tests/component/sidebar/Outline.test.tsx

@@ -0,0 +1,75 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { ThemeProvider } from '@/components/theme-provider';
+import { Outline } from '@/components/sidebar/Outline';
+import { useEditorStore } from '@/stores/editor-store';
+
+describe('Outline', () => {
+  beforeEach(() => {
+    useEditorStore.setState({ buffers: new Map(), activeId: null });
+  });
+
+  it('renders "No file open" when no active buffer', () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <Outline />
+      </ThemeProvider>
+    );
+    expect(screen.getByText(/no file open/i)).toBeInTheDocument();
+  });
+
+  it('renders H1-H6 headings from the active buffer content', () => {
+    const buffers = new Map([
+      [
+        'b1',
+        {
+          id: 'b1',
+          path: '/x.md',
+          content: '# Hello\n## World\n### Foo\n#### Bar\n##### Baz\n###### Qux',
+          dirty: false,
+        },
+      ],
+    ]);
+    useEditorStore.setState({ buffers, activeId: 'b1' });
+
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <Outline />
+      </ThemeProvider>
+    );
+
+    expect(screen.getByText('Hello')).toBeInTheDocument();
+    expect(screen.getByText('World')).toBeInTheDocument();
+    expect(screen.getByText('Foo')).toBeInTheDocument();
+    expect(screen.getByText('Bar')).toBeInTheDocument();
+    expect(screen.getByText('Baz')).toBeInTheDocument();
+    expect(screen.getByText('Qux')).toBeInTheDocument();
+  });
+
+  it('renders headings with level-based indent', () => {
+    const buffers = new Map([
+      [
+        'b1',
+        {
+          id: 'b1',
+          path: '/x.md',
+          content: '# Title\n## Subtitle\n### Section',
+          dirty: false,
+        },
+      ],
+    ]);
+    useEditorStore.setState({ buffers, activeId: 'b1' });
+
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <Outline />
+      </ThemeProvider>
+    );
+
+    const buttons = screen.getAllByRole('button');
+    // H1 has paddingLeft 8px, H2 has24px, H3 has 40px
+    expect(buttons[0]).toHaveStyle('padding-left: 8px');
+    expect(buttons[1]).toHaveStyle('padding-left: 24px');
+    expect(buttons[2]).toHaveStyle('padding-left: 40px');
+  });
+});

tests/component/sidebar/Sidebar.test.tsx

@@ -0,0 +1,92 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import { ThemeProvider } from '@/components/theme-provider';
+import { Sidebar } from '@/components/sidebar/Sidebar';
+import { useFileStore } from '@/stores/file-store';
+import { useEditorStore } from '@/stores/editor-store';
+
+vi.mock('@/lib/ipc', () => ({
+  ipc: {
+    file: {
+      pickFolder: vi.fn(),
+      list: vi.fn(),
+      pickFile: vi.fn(),
+      read: vi.fn(),
+      write: vi.fn(),
+    },
+  },
+}));
+
+describe('Sidebar', () => {
+  beforeEach(() => {
+    useFileStore.setState({ tree: null, rootPath: null, expanded: new Set(), openTabs: [], activeTabId: null });
+    useEditorStore.setState({ buffers: new Map(), activeId: null });
+  });
+
+  it('renders without crashing with empty state in both sections', () => {
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <Sidebar />
+      </ThemeProvider>
+    );
+    expect(screen.getByText('Files')).toBeInTheDocument();
+    expect(screen.getByText('Outline')).toBeInTheDocument();
+    expect(screen.getByText(/no folder opened/i)).toBeInTheDocument();
+    expect(screen.getByText(/no file open/i)).toBeInTheDocument();
+  });
+
+  it('renders FileTree and Outline sections', () => {
+    useFileStore.setState({
+      tree: {
+        name: 'project',
+        path: '/project',
+        isDirectory: true,
+        loaded: true,
+        children: [{ name: 'README.md', path: '/project/README.md', isDirectory: false, children: null }],
+      },
+      rootPath: '/project',
+    });
+
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <Sidebar />
+      </ThemeProvider>
+    );
+
+    expect(screen.getByText('Files')).toBeInTheDocument();
+    expect(screen.getByText('Outline')).toBeInTheDocument();
+    expect(screen.getByText('README.md')).toBeInTheDocument();
+  });
+
+  it('renders "Open Folder" button when no folder is open', () => {
+    useFileStore.setState({ tree: null, rootPath: null });
+
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <Sidebar />
+      </ThemeProvider>
+    );
+
+    expect(screen.getByText(/no folder opened/i)).toBeInTheDocument();
+    const btn = screen.getByRole('button', { name: /open folder/i });
+    expect(btn).toBeInTheDocument();
+  });
+
+  it('clicking "Open Folder" button calls openFolderDialog', async () => {
+    const { ipc } = await import('@/lib/ipc');
+    const spy = vi.spyOn(useFileStore.getState(), 'openFolderDialog');
+
+    useFileStore.setState({ tree: null, rootPath: null });
+
+    render(
+      <ThemeProvider defaultTheme="dark" attribute="class">
+        <Sidebar />
+      </ThemeProvider>
+    );
+
+    const btn = screen.getByRole('button', { name: /open folder/i });
+    fireEvent.click(btn);
+
+    expect(spy).toHaveBeenCalled();
+  });
+});

tests/component/theme-toggle.test.tsx

@@ -0,0 +1,40 @@
+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 { ThemeToggle } from '@/components/theme-toggle';
+
+Object.defineProperty(window, 'matchMedia', {
+  writable: true,
+  value: vi.fn().mockImplementation((query) => ({
+    matches: false,
+    media: query,
+    onchange: null,
+    addListener: vi.fn(),
+    removeListener: vi.fn(),
+    addEventListener: vi.fn(),
+    removeEventListener: vi.fn(),
+    dispatchEvent: vi.fn(),
+  })),
+});
+
+describe('ThemeToggle', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    document.documentElement.classList.remove('dark', 'light');
+  });
+
+  it('toggles between light and dark when clicked', async () => {
+    render(
+      <ThemeProvider defaultTheme="light" attribute="class">
+        <ThemeToggle />
+      </ThemeProvider>
+    );
+    const btn = screen.getByRole('button');
+    expect(btn).toHaveAccessibleName(/toggle theme/i);
+    await userEvent.click(btn);
+    expect(document.documentElement.classList.contains('dark')).toBe(true);
+    await userEvent.click(btn);
+    expect(document.documentElement.classList.contains('light')).toBe(true);
+  });
+});

tests/component/ui/button.test.tsx

@@ -0,0 +1,24 @@
+import { describe, it, expect } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { Button } from '@/components/ui/button';
+
+describe('Button', () => {
+  it('renders children', () => {
+    render(<Button>Click me</Button>);
+    expect(screen.getByRole('button', { name: /click me/i })).toBeInTheDocument();
+  });
+
+  it('calls onClick when clicked', async () => {
+    let count = 0;
+    render(<Button onClick={() => count++}>+</Button>);
+    await userEvent.click(screen.getByRole('button'));
+    expect(count).toBe(1);
+  });
+
+  it('renders the brand variant with primary styling', () => {
+    render(<Button variant="default">Brand</Button>);
+    const btn = screen.getByRole('button');
+    expect(btn.className).toContain('bg-primary');
+  });
+});

tests/git-operations.test.js

@@ -0,0 +1,123 @@
+/**
+ * Git Operations Utilities Test Suite
+ * Tests for async patterns and error handling
+ * @version 4.3.0
+ */
+
+describe('GitOperations Utilities', () => {
+  describe('error handling patterns', () => {
+    it('should handle git errors gracefully', () => {
+      const errorResponse = { error: 'Not a git repository' };
+      
+      expect(errorResponse).toHaveProperty('error');
+      expect(errorResponse.error).toContain('repository');
+    });
+
+    it('should return error object on failure', () => {
+      const failureResult = { error: 'Failed to commit' };
+      
+      expect(failureResult).toBeDefined();
+      expect(failureResult.error).toBeTruthy();
+    });
+  });
+
+  describe('async patterns', () => {
+    it('should handle async operations', async () => {
+      const asyncFn = async () => {
+        return { status: 'success' };
+      };
+
+      const result = await asyncFn();
+      expect(result).toHaveProperty('status');
+    });
+
+    it('should handle async errors', async () => {
+      const asyncFnWithError = async () => {
+        throw new Error('Git operation failed');
+      };
+
+      try {
+        await asyncFnWithError();
+        expect(true).toBe(false); // Should not reach here
+      } catch (err) {
+        expect(err.message).toContain('Git');
+      }
+    });
+  });
+
+  describe('git operations', () => {
+    it('should document expected operations', () => {
+      const gitOps = [
+        'getStatus',
+        'stage',
+        'commit',
+        'log',
+        'diff',
+        'branch',
+        'checkout',
+        'push',
+        'pull'
+      ];
+
+      expect(gitOps.length).toBeGreaterThan(0);
+      gitOps.forEach(op => {
+        expect(typeof op).toBe('string');
+        expect(op.length).toBeGreaterThan(0);
+      });
+    });
+
+    it('should handle directory paths', () => {
+      const paths = [
+        '/home/user/project',
+        './current/dir',
+        '../parent/dir'
+      ];
+
+      paths.forEach(pathStr => {
+        expect(typeof pathStr).toBe('string');
+        expect(pathStr.length).toBeGreaterThan(0);
+      });
+    });
+
+    it('should handle commit messages', () => {
+      const messages = [
+        'fix: bug in git panel',
+        'feat: add new feature',
+        'refactor: clean up code'
+      ];
+
+      messages.forEach(msg => {
+        expect(typeof msg).toBe('string');
+        expect(msg.length).toBeGreaterThan(0);
+      });
+    });
+  });
+
+  describe('response structures', () => {
+    it('should return status info', () => {
+      const statusResponse = {
+        conflicted: [],
+        created: [],
+        deleted: [],
+        modified: [],
+        renamed: [],
+        staged: ['file.md']
+      };
+
+      expect(statusResponse).toHaveProperty('staged');
+      expect(Array.isArray(statusResponse.staged)).toBe(true);
+    });
+
+    it('should return log entries', () => {
+      const logResponse = {
+        all: [
+          { hash: 'abc123', message: 'fix: something' }
+        ],
+        latest: { hash: 'abc123', message: 'fix: something' }
+      };
+
+      expect(logResponse).toHaveProperty('all');
+      expect(Array.isArray(logResponse.all)).toBe(true);
+    });
+  });
+});

tests/integration/phase5-smoke.test.tsx

@@ -0,0 +1,162 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { render, screen, fireEvent, act } from '@testing-library/react';
+import { AppShell } from '@/components/layout/AppShell';
+import { useFileStore } from '@/stores/file-store';
+import { useEditorStore } from '@/stores/editor-store';
+import { useAppStore } from '@/stores/app-store';
+
+// Mock react-resizable-panels for jsdom (same pattern as AppShell.test.tsx)
+vi.mock('@/components/ui/resizable', () => ({
+  ResizablePanelGroup: ({ children, direction }: any) => (
+    <div data-testid="resizable-panel-group" data-direction={direction}>
+      {children}
+    </div>
+  ),
+  ResizablePanel: ({ children, defaultSize }: any) => (
+    <div data-testid="resizable-panel" data-size={defaultSize}>
+      {children}
+    </div>
+  ),
+  ResizableHandle: () => <div data-testid="resizable-handle" />,
+}));
+
+vi.mock('@/lib/ipc', () => ({
+  ipc: {
+    file: {
+      open: vi.fn().mockResolvedValue({ ok: false, error: { code: 'NO_BRIDGE', message: 'mock' } }),
+      read: vi.fn().mockResolvedValue({ ok: true, data: '# hello' }),
+      write: vi.fn().mockResolvedValue({ ok: true, data: undefined }),
+      list: vi.fn().mockResolvedValue({
+        ok: true,
+        data: [
+          { name: 'README.md', path: '/root/README.md', isDirectory: false },
+          { name: 'src', path: '/root/src', isDirectory: true },
+        ],
+      }),
+      pickFolder: vi.fn().mockResolvedValue({ ok: true, data: '/root' }),
+      pickFile: vi.fn().mockResolvedValue({ ok: true, data: '/root/README.md' }),
+      onChange: vi.fn(() => () => {}),
+    },
+  },
+}));
+
+describe('Phase 5 integration', () => {
+  beforeEach(() => {
+    localStorage.clear();
+    useFileStore.setState({
+      tree: null,
+      rootPath: null,
+      expanded: new Set(),
+      openTabs: [],
+      activeTabId: null,
+    });
+    useEditorStore.setState({ buffers: new Map(), activeId: null });
+    useAppStore.setState({
+      sidebarVisible: true,
+      previewVisible: true,
+      zenMode: false,
+      paneSizes: { sidebar: 20, editor: 50, preview: 30 },
+    });
+  });
+
+  it('AppShell renders Sidebar (Files + Outline sections) and TabBar', () => {
+    render(<AppShell />);
+    expect(screen.getByText('Files')).toBeInTheDocument();
+    expect(screen.getByText('Outline')).toBeInTheDocument();
+    expect(screen.getByText(/no files open/i)).toBeInTheDocument();
+  });
+
+  it('opening a folder via the Open Folder button populates the tree', async () => {
+    render(<AppShell />);
+    const openBtn = screen.getByRole('button', { name: /open folder/i });
+    await act(async () => {
+      fireEvent.click(openBtn);
+    });
+    // After openFolder, the tree should have children
+    const state = useFileStore.getState();
+    expect(state.tree).not.toBeNull();
+    expect(state.tree?.children).toHaveLength(2);
+    expect(state.rootPath).toBe('/root');
+  });
+
+  it('clicking a file in the tree opens it as a tab and populates the editor buffer', async () => {
+    // Seed the tree directly
+    useFileStore.setState({
+      tree: {
+        name: 'root',
+        path: '/root',
+        isDirectory: true,
+        loaded: true,
+        children: [
+          { name: 'README.md', path: '/root/README.md', isDirectory: false, children: null },
+        ],
+      },
+      rootPath: '/root',
+      openTabs: [],
+      activeTabId: null,
+    });
+
+    render(<AppShell />);
+    const fileButton = screen.getByText('README.md').closest('button')!;
+    await act(async () => {
+      fireEvent.click(fileButton);
+    });
+
+    const state = useFileStore.getState();
+    expect(state.openTabs).toHaveLength(1);
+    expect(state.openTabs[0].id).toBe('/root/README.md');
+    expect(state.activeTabId).toBe('/root/README.md');
+
+    // Editor buffer should have the file content
+    const buf = useEditorStore.getState().buffers.get('/root/README.md');
+    expect(buf?.content).toBe('# hello');
+  });
+
+  it('TabBar shows the open tab and switches active on click', async () => {
+    useFileStore.setState({
+      tree: null,
+      rootPath: null,
+      expanded: new Set(),
+      openTabs: [
+        { id: '/a.md', path: '/a.md', title: 'a.md', dirty: false },
+        { id: '/b.md', path: '/b.md', title: 'b.md', dirty: false },
+      ],
+      activeTabId: '/a.md',
+    });
+    render(<AppShell />);
+    const aTab = screen.getByText('a.md').closest('[role="tab"]')!;
+    const bTab = screen.getByText('b.md').closest('[role="tab"]')!;
+    expect(aTab).toHaveAttribute('aria-current', 'page');
+    await act(async () => {
+      fireEvent.click(bTab);
+    });
+    expect(useFileStore.getState().activeTabId).toBe('/b.md');
+  });
+
+  it('keyboard shortcut Ctrl+S triggers saveActiveBuffer (no-op when no active tab)', () => {
+    render(<AppShell />);
+    fireEvent.keyDown(window, { key: 's', ctrlKey: true });
+    // No assertion on side effect, just confirms it doesn't throw
+    expect(useFileStore.getState().openTabs).toHaveLength(0);
+  });
+
+  it('drag-reorder updates the openTabs order', () => {
+    useFileStore.setState({
+      tree: null,
+      rootPath: null,
+      expanded: new Set(),
+      openTabs: [
+        { id: '/a.md', path: '/a.md', title: 'a.md', dirty: false },
+        { id: '/b.md', path: '/b.md', title: 'b.md', dirty: false },
+        { id: '/c.md', path: '/c.md', title: 'c.md', dirty: false },
+      ],
+      activeTabId: '/a.md',
+    });
+    render(<AppShell />);
+    act(() => {
+      useFileStore.getState().reorderTabs(0, 2);
+    });
+    const order = useFileStore.getState().openTabs.map((t) => t.id);
+    expect(order).toEqual(['/b.md', '/c.md', '/a.md']);
+  });
+});