test(renderer): Phase 6 integration smoke test (menu -> command -> store)

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

.github/workflows/ci.yml

@@ -23,3 +23,6 @@ jobs:
 
       - name: Run tests
         run: npm test
+
+      - name: Run linter
+        run: npm run lint

.github/workflows/release.yml

@@ -19,17 +19,17 @@ jobs:
           node-version: 20
           cache: npm
 
-      - name: Install rpmbuild
-        run: sudo apt-get update && sudo apt-get install -y rpm
-
       - name: Install dependencies
         run: npm ci
 
+      - name: Download external tools (pandoc)
+        run: node scripts/download-tools.js
+
       - name: Run tests
         run: npm test
 
       - name: Build Linux packages
-        run: npm run build:linux
+        run: npm run build:linux-ci -- --publish=never
 
       - name: Upload Linux artifacts
         uses: actions/upload-artifact@v4
@@ -43,7 +43,7 @@ jobs:
           retention-days: 5
 
   build-windows:
-    runs-on: ubuntu-latest
+    runs-on: windows-latest
     steps:
       - uses: actions/checkout@v4
 
@@ -53,17 +53,37 @@ jobs:
           node-version: 20
           cache: npm
 
-      - name: Install Wine and NSIS
-        run: |
-          sudo dpkg --add-architecture i386
-          sudo apt-get update
-          sudo apt-get install -y wine64 wine32 nsis
-
       - name: Install dependencies
         run: npm ci
 
-      - name: Build Windows packages
-        run: npm run build:win
+      - name: Download external tools (pandoc)
+        run: node scripts/download-tools.js
+
+      - name: Run tests
+        run: npm test
+
+      - name: Decode certificate (if available)
+        if: ${{ env.CSC_LINK_BASE64 != '' }}
+        shell: pwsh
+        env:
+          CSC_LINK_BASE64: ${{ secrets.CSC_LINK_BASE64 }}
+        run: |
+          $bytes = [Convert]::FromBase64String("$env:CSC_LINK_BASE64")
+          [IO.File]::WriteAllBytes("${{ github.workspace }}\code-signing-cert.pfx", $bytes)
+          echo "CERT_AVAILABLE=true" >> $env:GITHUB_ENV
+
+      - name: Build Windows packages (signed)
+        if: ${{ env.CERT_AVAILABLE == 'true' }}
+        env:
+          CSC_LINK: code-signing-cert.pfx
+          CSC_KEY_PASSWORD: ${{ secrets.CSC_KEY_PASSWORD }}
+        run: npm run build:win-signed -- --publish=never
+
+      - name: Build Windows packages (unsigned)
+        if: ${{ env.CERT_AVAILABLE != 'true' }}
+        env:
+          CSC_IDENTITY_AUTO_DISCOVERY: 'false'
+        run: npm run build:win-unsigned -- --publish=never
 
       - name: Upload Windows artifacts
         uses: actions/upload-artifact@v4
@@ -71,23 +91,26 @@ jobs:
           name: windows-artifacts
           path: |
             dist/*.exe
-            dist/*-win.zip
+            dist/*.zip
           retention-days: 5
 
   release:
     needs: [build-linux, build-windows]
+    if: always()
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
 
       - name: Download Linux artifacts
         uses: actions/download-artifact@v4
+        continue-on-error: true
         with:
           name: linux-artifacts
           path: dist
 
       - name: Download Windows artifacts
         uses: actions/download-artifact@v4
+        continue-on-error: true
         with:
           name: windows-artifacts
           path: dist

.gitignore

@@ -8,14 +8,22 @@ Thumbs.db
 *.swp
 *.swo
 *~
-.vscode/
+.vscode/*
+!.vscode/launch.json
 .idea/
 *.iml
 out/
 .cache/
 .npm/
 .electron/
-package-lock.json
+# package-lock.json is intentionally tracked for reproducible CI builds
+
+# Downloaded tool binaries (fetched at build time via scripts/download-tools.js)
+bin/
+
+# Code signing certificates — never commit private keys
+*.pfx
+*.p12
 
 # Screenshots and temp files
 *.png.bak
@@ -33,4 +41,8 @@ pdf\ modal.png
 # Claude/AI development files
 .claude/
 CLAUDE.md
-agents.mdcoverage/
+agents.md
+coverage/
+
+# Superpowers brainstorm artifacts
+.superpowers/

.vscode/launch.json

@@ -0,0 +1,48 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Debug Main Process",
+      "type": "node",
+      "request": "launch",
+      "cwd": "${workspaceFolder}",
+      "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron",
+      "windows": {
+        "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron.cmd"
+      },
+      "args": ["."],
+      "outputCapture": "std",
+      "env": {
+        "NODE_ENV": "development"
+      }
+    },
+    {
+      "name": "Debug Renderer Process",
+      "type": "chrome",
+      "request": "attach",
+      "port": 9222,
+      "webRoot": "${workspaceFolder}/src",
+      "timeout": 30000
+    },
+    {
+      "name": "Debug Main + Renderer",
+      "type": "node",
+      "request": "launch",
+      "cwd": "${workspaceFolder}",
+      "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron",
+      "windows": {
+        "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron.cmd"
+      },
+      "args": [".", "--remote-debugging-port=9222"],
+      "outputCapture": "std",
+      "env": {
+        "NODE_ENV": "development"
+      },
+      "serverReadyAction": {
+        "pattern": "listening on port ([0-9]+)",
+        "uriFormat": "http://localhost:%s",
+        "action": "debugWithChrome"
+      }
+    }
+  ]
+}

AGENTS.md

@@ -0,0 +1,25 @@
+# Repository Guidelines
+
+## Project Structure & Module Organization
+Core application code lives in `src/`. Use `src/main.js` for the Electron main process, `src/preload.js` for the preload bridge, and `src/renderer.js` plus `src/editor/`, `src/sidebar/`, `src/repl/`, and `src/utils/` for renderer-side features. Electron adapter code is in `src/adapters/electron/`. Reusable markdown/document templates live in `src/templates/`. Static assets and icons are in `assets/`. Tests are in `tests/`, and build output goes to `dist/`.
+
+## Build, Test, and Development Commands
+- `npm start`: launch the Electron app locally.
+- `npm test`: run the Jest suite once.
+- `npm run test:watch`: rerun tests during local development.
+- `npm run test:coverage`: generate coverage output.
+- `npm run lint` / `npm run lint:fix`: check or fix ESLint issues in `src` and `tests`.
+- `npm run format` / `npm run format:check`: apply or verify Prettier formatting.
+- `npm run build:linux`, `npm run build:win`, `npm run build:mac`: create platform packages with `electron-builder`.
+
+## Coding Style & Naming Conventions
+This repo uses Prettier and ESLint. Follow `.prettierrc`: 2-space indentation, single quotes, semicolons, trailing commas where valid in ES5, and a 100-character line width. Prefer `camelCase` for variables/functions, `PascalCase` for classes, and kebab-case for file names only when already established. Keep module boundaries clear: UI logic in renderer modules, OS/file-system work behind Electron IPC and adapters.
+
+## Testing Guidelines
+Tests use Jest with `jest-environment-jsdom`. Add new tests under `tests/` with `*.test.js` names, mirroring the feature area when possible, for example `tests/sidebar.test.js` or `tests/print-preview.test.js`. Update or add regression tests for renderer behavior, preload APIs, and utility helpers when fixing bugs. Run `npm test` before opening a PR; use `npm run test:coverage` for larger refactors.
+
+## Commit & Pull Request Guidelines
+Recent history follows Conventional Commit prefixes such as `feat:`, `fix:`, and `refactor:`. Keep subjects short and imperative, for example `fix: guard modal cleanup on close`. PRs should describe the user-visible change, note test coverage, link any related issue, and include screenshots or GIFs for UI changes.
+
+## Security & Configuration Tips
+Do not bypass preload boundaries or introduce direct `eval`/dynamic code paths; ESLint already treats these as errors. Export and conversion features depend on external tools such as Pandoc, FFmpeg, ImageMagick, and LibreOffice, so document any new runtime dependency in `README.md` and packaging config.

README.md

@@ -162,4 +162,4 @@ Amit Haridas (amit.wh@gmail.com)
 
 ## Version
 
-v3.0.0
+v4.1.0

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/THREAT_MODEL.md

@@ -1,6 +1,6 @@
 # MarkdownConverter - STRIDE Threat Model Analysis
 
-**Version:** 4.0.0
+**Version:** 4.1.0
 **Date:** 2026-03-15
 **Methodology:** STRIDE + MITRE ATT&CK Mapping
 **Analyst:** Security Assessment Team

docs/plans/2026-04-06-writers-studio-design.md

@@ -0,0 +1,335 @@
+# Writer's Studio Feature Pack — Design Document
+
+**Date**: 2026-04-06
+**Version**: 4.2.0 target
+**Status**: Approved
+**Scope**: Three cohesive features to transform MarkdownConverter into a writing environment
+
+---
+
+## Overview
+
+The Writer's Studio Feature Pack adds three interconnected features to MarkdownConverter:
+
+1. **Zen Mode** — Distraction-free writing environment with typewriter scrolling
+2. **Document Outline** — Heading hierarchy sidebar panel for navigation
+3. **Writing Analytics** — Real-time readability and vocabulary analysis dashboard
+
+These features work together: Zen Mode creates the environment, Outline provides navigation, Analytics gives insight.
+
+---
+
+## Feature 1: Zen Mode
+
+### Purpose
+
+Transform the app from a multi-tool into a focused writing environment. Inspired by iA Writer, Typora, and Bear.
+
+### New Files
+
+- `src/zen-mode.js` — ZenMode class (~150 lines)
+- `src/styles-zen.css` — Zen mode specific styles (~120 lines)
+
+### Integration Points
+
+- `src/renderer.js` — Initialize ZenMode, register F11 shortcut, add View > Zen Mode menu
+- `src/editor/codemirror-setup.js` — Export typewriter + dimming extensions
+
+### Behavior
+
+**Toggle**: F11, View > Zen Mode, command palette "Toggle Zen Mode"
+**Exit**: Escape key, F11 again
+
+**What hides**:
+- Tab bar
+- Toolbar
+- Sidebar (collapsed)
+- Status bar
+- App header
+
+**What shows**:
+- Editor (full viewport)
+- Floating HUD (bottom-center, semi-transparent)
+
+### Floating HUD
+
+```
+┌─────────────────────────────────────────┐
+│  847 words  •  ~4 min  •  23:45 session │
+│  ████████████████░░░░  85% of 1000      │
+└─────────────────────────────────────────┘
+```
+
+- Word count (from existing status bar logic)
+- Estimated reading time (~200 wpm)
+- Session timer (starts when zen mode activates)
+- Optional progress bar toward word goal
+
+### CodeMirror Extensions
+
+**Typewriter Scroll** (`ViewPlugin`):
+- Listens to `EditorView.update` for selection changes
+- Calls `editor.dispatch({ effects: EditorView.scrollIntoView(pos, { y: 'center' }) })`
+- Smooth scrolling with `scrollBehavior: 'smooth'` in CSS
+
+**Line Dimming** (`ViewPlugin` + `Decoration`):
+- Builds a `DecorationSet` mapping each line to an opacity value
+- Active line: opacity 1.0
+- 1-2 lines away: 0.7
+- 3-4 lines away: 0.5
+- 5+ lines away: 0.3
+- Uses `Decoration.line({ attributes: { style: 'opacity: X' } })`
+
+### Centered Column
+
+CSS applied to `.zen-mode .cm-content`:
+```css
+.zen-mode .cm-content {
+    max-width: 700px;
+    margin: 0 auto;
+    font-size: 18px;
+    line-height: 1.8;
+}
+```
+
+### State Management
+
+- `this.previousState` stores which UI elements were visible before zen mode
+- On exit, restores all elements to their previous visibility
+- Editor content, cursor position, and scroll state are never modified
+
+---
+
+## Feature 2: Document Outline Panel
+
+### Purpose
+
+Provide always-visible heading navigation for documents of any length. The single most-requested navigation feature for multi-section documents.
+
+### New Files
+
+- `src/sidebar/outline-panel.js` — `renderOutlinePanel` function (~100 lines)
+
+### Modified Files
+
+- `src/index.html` — Add outline icon button in sidebar icons strip
+- `src/renderer.js` — Register 'outline' panel, provide editor reference
+
+### Sidebar Integration
+
+Uses existing `SidebarManager.registerPanel()` API:
+```javascript
+sidebarManager.registerPanel('outline', {
+    title: 'Outline',
+    render: (container) => renderOutlinePanel(container, editor, editorContent)
+});
+```
+
+New icon button in sidebar strip (after templates icon):
+```html
+<button class="sidebar-icon" data-panel="outline" title="Outline (Ctrl+Shift+O)">
+    <!-- hierarchy/list icon SVG -->
+</button>
+```
+
+### Parsing Logic
+
+Parse headings from raw markdown content using regex:
+```javascript
+const headingRegex = /^(#{1,6})\s+(.+)$/gm;
+```
+
+Returns array of:
+```javascript
+{ level: 1-6, text: "Heading Text", line: 42 }
+```
+
+Debounced at 300ms to avoid re-parsing on every keystroke.
+
+### UI Structure
+
+```
+┌──────────────────────────────────────────┐
+│  OUTLINE                          ☰      │
+├──────────────────────────────────────────┤
+│  ▸ Introduction                  (H1)    │
+│    ▸ Getting Started             (H2)    │
+│    ▸ Prerequisites               (H2)    │
+│      ▸ Node.js                   (H3) ◄  │
+│    ▸ Installation                (H2)    │
+│  ▸ Features                      (H1)    │
+│    ▸ Editor                      (H2)    │
+│    ▸ Export                      (H2)    │
+├──────────────────────────────────────────┤
+│  9 headings  •  2 H1  •  4 H2  •  3 H3  │
+└──────────────────────────────────────────┘
+```
+
+- Indentation based on heading level (H1 = 0px, H2 = 16px, H3 = 32px, etc.)
+- Current heading highlighted with accent color (◄ indicator)
+- Hover shows full heading text if truncated
+
+### Click-to-Navigate
+
+```javascript
+editor.dispatch({
+    effects: EditorView.scrollIntoView(linePos, { y: 'center' })
+});
+```
+
+Brief highlight animation on the target line (fades out over 500ms).
+
+### Current Heading Sync
+
+On editor update (debounced 100ms):
+1. Get cursor line number
+2. Find the last heading whose line number <= cursor line
+3. Set that heading as active in the outline
+
+### Empty State
+
+When no headings found:
+```
+No headings found
+
+Use # to create headings:
+# Heading 1
+## Heading 2
+### Heading 3
+```
+
+---
+
+## Feature 3: Writing Analytics
+
+### Purpose
+
+Give writers real-time insight into their document's readability, structure, and vocabulary. This is the "surprise" feature most Markdown editors lack.
+
+### New Files
+
+- `src/analytics/writing-analytics.js` — `WritingAnalytics` class (~180 lines)
+- `src/analytics/analytics-panel.js` — `renderAnalyticsPanel` function (~120 lines)
+
+### Integration Points
+
+- `src/renderer.js` — Register Ctrl+Shift+A shortcut, command palette entry, View menu item
+
+### Trigger
+
+- Keyboard: `Ctrl+Shift+A`
+- Command Palette: "Show Writing Analytics"
+- Menu: View > Writing Analytics
+
+### Presentation
+
+Uses existing `ModalManager` to show a modal overlay with analytics dashboard.
+
+```
+┌─────────────────────────────────────────────────────┐
+│  Writing Analytics                              ✕   │
+├─────────────────────────────────────────────────────┤
+│                                                      │
+│  ┌─ Readability ──────────────────────────────────┐ │
+│  │  Flesch Reading Ease:  67.3 (Standard)    ○   │ │
+│  │  Grade Level:          8.2              ○○○●○  │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+│  ┌─ Timing ───────────────────────────────────────┐ │
+│  │  Reading Time:   ~4 min                        │ │
+│  │  Speaking Time:  ~6 min                        │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+│  ┌─ Structure ────────────────────────────────────┐ │
+│  │  Sentences:  42  •  Paragraphs:  8            │ │
+│  │  Avg Sentence:  14.2 words                     │ │
+│  │  Longest:  38 words ("The quick brown fox...") │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+│  ┌─ Vocabulary ───────────────────────────────────┐ │
+│  │  Unique: 312 / 847 words (36.8%)               │ │
+│  │  Top: the(42) and(31) markdown(28) ...         │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+│  ┌─ Word Goal ────────────────────────────────────┐ │
+│  │  Target: [1000] words                          │ │
+│  │  ████████████████░░░░  847/1000 (85%)          │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+└─────────────────────────────────────────────────────┘
+```
+
+### Metrics Implementation
+
+**Readability (Flesch-Kincaid):**
+```javascript
+// Flesch Reading Ease
+ease = 206.835 - 1.015 * (words / sentences) - 84.6 * (syllables / words);
+
+// Flesch-Kincaid Grade Level
+grade = 0.39 * (words / sentences) + 11.8 * (syllables / words) - 15.59;
+```
+
+**Syllable Estimation:**
+```javascript
+function countSyllables(word) {
+    word = word.toLowerCase().replace(/(?:[^laeiouy]es|ed|[^laeiouy]e)$/, '');
+    word = word.replace(/^y/, '');
+    return word.match(/[aeiouy]{1,2}/g)?.length || 1;
+}
+```
+
+**Reading/Speaking Time:**
+- Reading: 200 words/minute
+- Speaking: 130 words/minute
+
+**Lexical Diversity:**
+- Ratio of unique words to total words (excluding stop words)
+
+**Top Words:**
+- Frequency map, sorted descending, top 10
+- Excludes common stop words (the, a, an, is, are, etc.)
+
+### Word Goal
+
+- Persisted in `electron-store` per document (or global default)
+- Progress bar with percentage
+- Celebration effect when goal is reached (brief confetti animation or green flash)
+
+### Update Cadence
+
+- Re-analyzes on editor content change (debounced at 1000ms)
+- If modal is open, updates live
+- If modal is closed, no computation (zero overhead)
+
+---
+
+## File Summary
+
+| File | Action | Purpose |
+|------|--------|---------|
+| `src/zen-mode.js` | Create | ZenMode class with CM6 extensions |
+| `src/styles-zen.css` | Create | Zen mode styling |
+| `src/sidebar/outline-panel.js` | Create | Outline sidebar panel |
+| `src/analytics/writing-analytics.js` | Create | Analytics computation engine |
+| `src/analytics/analytics-panel.js` | Create | Analytics modal UI |
+| `src/index.html` | Modify | Add outline icon, zen mode button |
+| `src/renderer.js` | Modify | Initialize all three features |
+| `src/editor/codemirror-setup.js` | Modify | Export typewriter + dimming extensions |
+
+## Keyboard Shortcuts
+
+| Shortcut | Feature | Action |
+|----------|---------|--------|
+| F11 | Zen Mode | Toggle on/off |
+| Escape | Zen Mode | Exit (when active) |
+| Ctrl+Shift+O | Outline | Open outline sidebar panel |
+| Ctrl+Shift+A | Analytics | Open analytics modal |
+
+## Dependencies
+
+No new npm dependencies required. All features use:
+- Existing CodeMirror 6 APIs (ViewPlugin, Decoration, scrollIntoView)
+- Existing SidebarManager API
+- Existing ModalManager API
+- Pure JavaScript math for analytics

docs/superpowers/specs/2026-04-14-v5-platform-design.md

@@ -0,0 +1,426 @@
+# MarkdownConverter v5.0 — Platform Design
+
+**Date:** 2026-04-14
+**Status:** Approved
+**Author:** Amit Haridas
+
+## Overview
+
+Transform MarkdownConverter from a monolithic editor into an extensible platform with a plugin system and three feature packs, shipped together as v5.0.
+
+## Subsystems
+
+1. **Plugin System** — Lightweight plugin registry with extension points (sidebar, commands, settings, status bar, export hooks, event bus)
+2. **Writing Studio Plugin** — Manuscript manager, goal tracking, writing sprints, snapshots, smart proofreading
+3. **AI Assistant Plugin** — Multi-provider AI writing assistant (Ollama, LMStudio, GGUF direct with GPU, Anthropic, OpenAI)
+4. **Collaboration Plugin** — Git-based async collaboration, comments/annotations, review requests
+
+## Core Principle
+
+**Existing functionality is never replaced or broken.** The plugin system is additive. All existing keyboard shortcuts, features, and UI remain untouched. Plugin shortcuts use `Ctrl+Alt+` namespace.
+
+---
+
+## 1. Plugin System
+
+### File Structure
+
+```
+src/
+  plugins/
+    plugin-registry.js      # Load, register, lifecycle
+    plugin-api.js            # Base class plugins extend
+    plugin-loader.js         # Discovers and validates manifests
+    built-in/
+      writing-studio/
+        manifest.json
+        index.js
+        panels/
+        components/
+      ai-assistant/
+        manifest.json
+        index.js
+        providers/
+      collaboration/
+        manifest.json
+        index.js
+```
+
+### Manifest Schema
+
+```json
+{
+  "id": "writing-studio",
+  "name": "Writing Studio",
+  "version": "1.0.0",
+  "description": "Manuscript management, goal tracking, writing sprints",
+  "icon": "pen-tool",
+  "extensionPoints": {
+    "sidebar": { "panel": "panels/manuscript-panel.js", "order": 30 },
+    "settings": { "section": "settings/index.js" },
+    "statusBar": { "indicators": ["sprint-timer", "word-goal"] },
+    "commands": [
+      { "id": "start-sprint", "label": "Start Writing Sprint", "shortcut": "Ctrl+Alt+S" },
+      { "id": "take-snapshot", "label": "Take Snapshot", "shortcut": "Ctrl+Alt+N" }
+    ],
+    "exportHooks": {
+      "preExport": "hooks/pre-export.js",
+      "postExport": "hooks/post-export.js"
+    }
+  },
+  "settings": [
+    { "key": "dailyGoal", "type": "number", "default": 1000, "label": "Daily word goal" },
+    { "key": "sprintDuration", "type": "number", "default": 25, "label": "Sprint duration (min)" }
+  ]
+}
+```
+
+### Plugin Lifecycle
+
+1. PluginLoader discovers manifests in `built-in/` + user plugins directory
+2. PluginRegistry validates manifests
+3. Each plugin calls `Plugin.init(context)` receiving scoped API context
+4. Extension points registered (sidebar panels, commands, status bar items)
+5. Plugins activate lazily — sidebar panel loads JS when user clicks tab
+
+### Plugin Context API
+
+Each plugin's `init()` receives:
+
+```javascript
+{
+  sidebar: {
+    registerPanel(id, { icon, title, component })
+  },
+  commands: {
+    register(id, label, handler, shortcut?)
+  },
+  statusBar: {
+    registerIndicator(id, { position, render })
+  },
+  settings: {
+    get(key),                    // plugin-scoped
+    set(key, value),             // auto-persisted via electron-store
+    onChanged(key, callback)
+  },
+  editor: {
+    getContent(),                // current document
+    getSelection(),              // selected text
+    insertAtCursor(text),        // requires opt-in
+    onContentChanged(callback)
+  },
+  events: {
+    on(event, handler),
+    emit(event, data)
+  },
+  exports: {
+    registerPreHook(handler),
+    registerPostHook(handler)
+  },
+  ipc: {
+    invoke(channel, ...args),
+    on(channel, handler)
+  }
+}
+```
+
+### Event Bus Events
+
+Each event has a versioned payload schema. Breaking changes increment the version suffix.
+
+```
+document:opened        → { filePath: string, tabId: string }
+document:saved         → { filePath: string, tabId: string }
+document:changed       → { tabId: string, content: string, wordCount: number }
+editor:selection-changed → { tabId: string, text: string, from: {line,ch}, to: {line,ch} }
+tab:switched           → { tabId: string, filePath: string }
+tab:closed             → { tabId: string, filePath: string }
+export:started         → { format: string, filePath: string }
+export:completed       → { format: string, filePath: string, outputPath: string }
+export:failed          → { format: string, error: string }
+plugin:loaded          → { pluginId: string, version: string }
+plugin:activated       → { pluginId: string }
+plugin:deactivated     → { pluginId: string }
+app:ready              → {}
+app:before-quit        → {}
+```
+
+### Design Rules
+
+- Built-in plugins use the same API as future third-party plugins
+- Lazy activation — sidebar panels don't load until clicked
+- Scoped settings: `plugins.<id>.<key>` in electron-store
+- Plugin commands globally unique — registry rejects duplicate command IDs at load time
+- **Plugin sandboxing**: each plugin handler is wrapped in try/catch. For CPU-intensive operations (AI inference, diff computation), plugins must delegate to main process via IPC. Handlers that block the renderer for >5s trigger a warning notification. Memory-hungry operations (GGUF inference) run in isolated child processes.
+- **Cross-plugin graceful degradation**: plugins check `context.events.hasHandler('ai:analyze')` before emitting cross-plugin requests. If no handler (AI plugin disabled), show a "this feature requires the AI plugin" prompt instead of failing silently. All cross-plugin calls have a 30s timeout with default fallback behavior.
+
+---
+
+## 2. Writing Studio Plugin
+
+### 2A. Manuscript / Project Manager
+
+Folder-based project structure:
+
+```
+~/Manuscripts/
+  my-novel/
+    .project.json          # { title, targets, metadata }
+    01-chapter-one.md
+    02-chapter-two.md
+    characters/
+      protagonist.md
+    research/
+      world-building.md
+    .snapshots/
+      2026-04-14T10-30.json
+```
+
+`.project.json`:
+
+```json
+{
+  "title": "My Novel",
+  "type": "manuscript",
+  "target": { "words": 80000, "deadline": "2026-09-01" },
+  "chapters": [
+    { "file": "01-chapter-one.md", "title": "The Beginning", "status": "draft" }
+  ],
+  "metadata": { "author": "", "genre": "", "synopsis": "" }
+}
+```
+
+Sidebar panel shows project tree with drag-to-reorder, word counts per chapter, target progress bar. "Compile manuscript" exports all chapters as a single document.
+
+### 2B. Goal Tracking & Writing Sprints
+
+- **Status bar**: daily progress bar + sprint timer
+- **Writing sprint**: configurable duration (15/25/30/45/60 min), word count delta, WPM at end
+- **Goal tracking**: daily/weekly word goals, streak tracking, 30-day bar chart
+- **Enhanced analytics**: session tracking, readability scores, productive time-of-day heatmap
+- Data stored in `plugins.writing-studio.history` as date-keyed map
+
+### 2C. Snapshot & Versioning
+
+- `Ctrl+Alt+N` or toolbar button saves snapshot
+- Stored as JSON: `{ timestamp, content, wordCount, cursorPos, label }`
+- Snapshot panel in sidebar: Restore, Diff (side-by-side), auto-snapshot interval
+- Snapshots in `.snapshots/` inside project folder, or app data if no project
+
+### 2D. Smart Proofreading
+
+Delegates to AI plugin via event bus. Writing Studio provides:
+- Right-click context menu: "Check grammar", "Suggest alternatives", "Analyze readability"
+- Inline wavy underline decorations for issues
+- Proofread panel: issues categorized by type with Accept/Dismiss
+
+### Commands
+
+| Command | Shortcut | Action |
+|---------|----------|--------|
+| `start-sprint` | `Ctrl+Alt+S` | Start writing sprint |
+| `stop-sprint` | `Ctrl+Alt+Shift+S` | Stop sprint |
+| `take-snapshot` | `Ctrl+Alt+N` | Save snapshot |
+| `restore-last-snapshot` | `Ctrl+Alt+Z` | Restore latest snapshot |
+| `new-project` | — | Create manuscript project |
+| `compile-manuscript` | `Ctrl+Alt+E` | Export all chapters |
+| `proofread-document` | `Ctrl+Alt+G` | AI proofread |
+
+---
+
+## 3. AI Assistant Plugin
+
+### Provider Architecture
+
+```
+AI Plugin
+  ├── Provider Interface
+  │     ├── complete(prompt, options) → string
+  │     ├── stream(prompt, options) → AsyncIterable
+  │     └── analyze(text, type) → AnalysisResult
+  │
+  ├── Providers
+  │     ├── OllamaProvider      — localhost:11434
+  │     ├── LMStudioProvider    — localhost:1234/v1
+  │     ├── GGUFProvider         — direct llama.cpp with GPU support
+  │     ├── AnthropicProvider    — Claude API
+  │     └── OpenAIProvider       — GPT API
+  │
+  └── Features
+        ├── Grammar/style check
+        ├── Inline auto-complete
+        ├── AI chat panel (sidebar)
+        ├── Document analysis
+        └── Smart commands (command palette)
+```
+
+### Provider Details
+
+**Ollama:** `GET /api/tags` for models, `POST /api/generate` and `POST /api/chat` for inference.
+
+**LMStudio:** OpenAI-compatible API at `localhost:1234/v1`. `GET /v1/models`, standard chat completion format, SSE streaming.
+
+**GGUF Direct (with GPU):**
+- Ships bundled llama.cpp binaries per platform (CUDA, Vulkan, Metal, CPU variants)
+- Auto-detects GPU: CUDA (nvidia-smi), Vulkan driver, Metal (macOS)
+- GPU layer offloading: configurable, auto-suggests based on VRAM vs model size
+- Settings: GPU backend selection, layer count, context length, thread count
+- "Keep model loaded" option for faster repeated requests
+- WASM fallback for sandboxed environments (CPU-only)
+- External binary path for advanced users with custom builds
+- **Process isolation**: llama.cpp runs as a spawned child process (not in main process). If it crashes, detected via exit handler, auto-restarted with notification. GPU memory freed on crash. App remains stable.
+- Process management: spawn in server mode on localhost ephemeral port, clean up on app quit or model unload
+
+**Cloud (Anthropic/OpenAI):**
+- API key stored encrypted via electron safeStorage
+- Token usage tracking with estimated cost
+- Rate limit awareness with request queueing and backoff
+
+### IPC Design
+
+All provider HTTP requests go through main process:
+- No CORS issues
+- API keys never in renderer
+- Main process enforces rate limiting
+- GGUF inference in isolated child process
+
+**Request/response lifecycle:**
+```
+Renderer → ipc.invoke('ai:complete') → Main → HTTP to provider → result → Renderer
+```
+
+**Streaming lifecycle with error handling:**
+```
+Renderer → ipc.invoke('ai:stream', { requestId, prompt })
+         ← Main assigns requestId, returns { requestId }
+         ← ipc.on('ai:chunk', { requestId, text }) — repeated
+         ← ipc.on('ai:done', { requestId }) — success
+         ← ipc.on('ai:error', { requestId, error }) — failure
+
+// Cancellation
+Renderer → ipc.invoke('ai:cancel', { requestId })
+         ← Main aborts HTTP request, emits 'ai:done'
+
+// Orphan cleanup: if renderer disconnects (crash/close),
+// main process detects via 'render-view-deleted' and aborts all active streams.
+// Heartbeat: if no chunk received in 30s, main emits 'ai:error' with timeout.
+```
+
+### Features
+
+1. **Inline suggestions**: ghost text after configurable delay, Tab to accept, Esc to dismiss
+2. **AI chat panel**: sidebar conversation, "Insert" / "Replace selection" buttons
+3. **Document analysis**: grammar, style, tone, with accept/reject per suggestion
+4. **Smart commands**: summarize, generate outline, find inconsistencies, translate, explain code
+
+### Privacy
+
+- Local-first: default provider is Ollama
+- No telemetry: requests go direct to provider
+- Content gating: exclude file types from AI
+- Status bar shows "AI: processing..." with cancel option
+- Cloud usage stats in settings (tokens, cost)
+
+### Cross-Plugin Integration
+
+```javascript
+// Writing Studio calls AI Plugin
+context.events.emit('ai:analyze', { text, type: 'grammar', callback });
+```
+
+---
+
+## 4. Collaboration Plugin
+
+### 4A. Enhanced Git Panel
+
+Upgrades to existing git panel:
+- Remote management (add/remove remotes, push/pull)
+- Branch list and switching
+- Commit history with diff viewer (side-by-side or unified)
+- Conflict resolution UI (accept-ours/accept-theirs/per-edit)
+
+### 4B. Shared Repository Workflow
+
+1. Writer A creates project + initializes git + pushes to shared repo
+2. Writer B clones repo from within MarkdownConverter
+3. Both write on their own branches
+4. Writer A creates review request (simplified PR)
+
+Review request: changed files, word count diff, commit messages. Reviewer can approve, request changes, leave inline comments. Reviews are git branches + comments as git notes.
+
+### 4C. Comments & Annotations
+
+Inline comments stored as JSON in `.comments/` directory (git-tracked):
+```json
+{
+  "id": "uuid",
+  "file": "03-chapter-three.md",
+  "anchor": {
+    "contextBefore": "The hero looked at the horizon and said,",
+    "selectedText": "I will not go quietly into that dark night",
+    "contextAfter": "He turned to face the army alone."
+  },
+  "line": 142,
+  "text": "This dialogue feels unnatural",
+  "author": "amit",
+  "timestamp": "2026-04-14T14:30:00Z",
+  "replies": [],
+  "resolved": false
+}
+```
+
+- **Anchor-based positioning**: comments store `contextBefore`, `selectedText`, and `contextAfter` (not absolute byte offsets). On file change, re-anchor by searching for the context text. If context no longer matches, mark comment as "detached" and show a warning. Falls back to `line` number as rough position.
+- Highlighted text in editor with tooltip on hover
+- Comment panel in sidebar: all unresolved comments across files
+- Resolution workflow: add → address → reply → resolve
+- Resolved comments dim but stay visible
+
+### 4D. Change Notifications
+
+- Status bar indicator: `↓ 3 new commits`
+- Click to see changes, one-click pull
+- Conflicts trigger resolution UI
+- Push button only when local commits ahead of remote
+
+### 4E. Offline-First
+
+All writing happens locally. Git is the sync mechanism. No internet required for writing, commenting, snapshots, or sprints. Push/pull on user action or auto-sync setting.
+
+### Commands
+
+| Command | Shortcut | Action |
+|---------|----------|--------|
+| `collab:commit` | `Ctrl+Shift+G` | Commit with message |
+| `collab:push` | — | Push current branch |
+| `collab:pull` | — | Pull from remote |
+| `collab:add-comment` | `Ctrl+Alt+C` | Comment on selection |
+| `collab:next-comment` | `F8` | Next unresolved comment |
+| `collab:prev-comment` | `Shift+F8` | Previous comment |
+| `collab:create-review` | — | Create review request |
+
+### Cross-Plugin Integration
+
+```javascript
+context.events.emit('snapshot:created', { file, snapshotId });
+context.events.on('project:chapter-opened', (chapter) => { /* load comments */ });
+context.events.on('comment:added', (comment) => { /* AI could suggest fix */ });
+```
+
+---
+
+## Bundle Size Impact
+
+- llama.cpp binaries: ~15MB per GPU variant. Only target platform shipped. GPU variants (CUDA/Vulkan/Metal) downloaded on demand if user enables GGUF direct loading — not bundled by default. Only CPU fallback bundled (~15MB).
+- Plugin system core: ~30KB
+- Each built-in plugin: ~50-100KB
+- Diff library (jsdiff): ~15KB
+- Total estimated increase: ~20-30MB (core), additional ~30-50MB per GPU variant (lazy download)
+
+## Testing Strategy
+
+- Plugin system: unit tests for registry, loader, context API mocking
+- Each plugin: isolated unit tests, integration tests via plugin context
+- AI provider tests: mock HTTP responses, test streaming parsing
+- Git tests: use test repository fixture
+- E2E: verify plugin loading doesn't break existing features

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

@@ -1,6 +1,6 @@
 {
   "name": "markdown-converter",
-  "version": "4.1.0",
+  "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": {
@@ -8,19 +8,25 @@
     "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",
     "format:check": "prettier --check src tests",
     "build": "electron-builder",
     "build:win": "electron-builder --win",
-    "build:win-signed": "cross-env CSC_LINK=code-signing-cert.pfx CSC_KEY_PASSWORD=%CSC_KEY_PASSWORD% electron-builder --win",
+    "build:win-signed": "cross-env CSC_LINK=code-signing-cert.pfx electron-builder --win",
     "build:win-unsigned": "cross-env CSC_IDENTITY_AUTO_DISCOVERY=false electron-builder --win",
+    "create-cert": "powershell -ExecutionPolicy Bypass -File scripts/create-selfsigned-cert.ps1",
     "build:mac": "electron-builder --mac",
     "build:linux": "electron-builder --linux",
+    "build:linux-ci": "electron-builder --linux deb AppImage",
     "build:local": "electron-builder --linux --win",
     "dist": "electron-builder --publish=never",
     "dist:all": "electron-builder -mwl",
+    "download-tools": "node scripts/download-tools.js",
     "generate-icons": "node scripts/generate-icons.js"
   },
   "keywords": [
@@ -40,17 +46,38 @@
     "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": "^37.4.0",
+    "electron": "^41.1.1",
     "electron-builder": "^26.0.12",
     "eslint": "^9.39.2",
     "eslint-config-prettier": "^10.1.8",
     "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",
@@ -67,33 +94,56 @@
     "@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",
     "nth-check": "^2.1.1",
-    "lodash.pick": "npm:lodash@^4.17.21"
+    "lodash.pick": "npm:lodash@^4.17.21",
+    "lodash-es": "^4.18.1",
+    "lodash": "^4.17.21"
   },
   "build": {
     "appId": "com.concreteinfo.markdownconverter",
     "productName": "MarkdownConverter",
+    "copyright": "Copyright (C) 2024-2025 ConcreteInfo",
     "directories": {
       "output": "dist"
     },
@@ -105,6 +155,10 @@
       "node_modules/**/*",
       "package.json"
     ],
+    "asarUnpack": [
+      "node_modules/ffmpeg-static/**"
+    ],
+    "extraFiles": [],
     "fileAssociations": [
       {
         "ext": "md",
@@ -155,7 +209,15 @@
       ],
       "artifactName": "${productName}-${version}-${arch}.${ext}",
       "requestedExecutionLevel": "asInvoker",
-      "signAndEditExecutable": false
+      "legalTrademarks": "Copyright (C) 2024-2025 ConcreteInfo",
+      "verifyUpdateCodeSignature": false,
+      "signAndEditExecutable": false,
+      "extraFiles": [
+        {
+          "from": "bin/win32/pandoc.exe",
+          "to": "bin/pandoc.exe"
+        }
+      ]
     },
     "nsis": {
       "oneClick": false,
@@ -177,29 +239,24 @@
       "target": [
         "deb",
         "AppImage",
-        "snap",
-        "rpm"
+        "snap"
       ],
       "category": "Utility",
-      "maintainer": "ConcreteInfo <amit.wh@gmail.com>"
+      "maintainer": "ConcreteInfo <amit.wh@gmail.com>",
+      "extraFiles": [
+        {
+          "from": "bin/linux/pandoc",
+          "to": "bin/pandoc"
+        }
+      ]
     },
     "deb": {
       "depends": [
-        "pandoc",
-        "ffmpeg",
         "imagemagick",
         "libreoffice-common"
       ],
       "description": "Professional Markdown editor and universal file converter",
       "maintainer": "ConcreteInfo <amit.wh@gmail.com>"
-    },
-    "rpm": {
-      "depends": [
-        "pandoc",
-        "ffmpeg",
-        "ImageMagick",
-        "libreoffice-core"
-      ]
     }
   }
 }

postcss.config.js

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

scripts/create-selfsigned-cert.ps1

@@ -0,0 +1,59 @@
+# create-selfsigned-cert.ps1
+# Generates a self-signed code-signing certificate for local/development builds.
+#
+# Usage:
+#   powershell -ExecutionPolicy Bypass -File scripts/create-selfsigned-cert.ps1
+#   npm run create-cert
+#
+# Then build with:
+#   $env:CSC_LINK="code-signing-cert.pfx"; $env:CSC_KEY_PASSWORD="YourPassword"; npm run build:win-signed
+#
+# NOTE: Self-signed certificates will still show a SmartScreen warning for end users.
+# For production releases, obtain an OV or EV certificate from a trusted CA
+# (DigiCert, Sectigo, Certum, etc.). EV certificates bypass SmartScreen immediately.
+# Open-source projects can apply for free signing at https://signpath.io/
+
+param(
+    [string]$CertPassword = "MarkdownConverter2025",
+    [string]$OutputFile   = "code-signing-cert.pfx",
+    [string]$Subject      = "CN=ConcreteInfo, O=ConcreteInfo, L=India, C=IN"
+)
+
+Write-Host "Creating self-signed code-signing certificate..." -ForegroundColor Cyan
+
+# Create the certificate in the current user's certificate store
+$cert = New-SelfSignedCertificate `
+    -Type CodeSigningCert `
+    -Subject $Subject `
+    -CertStoreLocation "Cert:\CurrentUser\My" `
+    -NotAfter (Get-Date).AddYears(3) `
+    -HashAlgorithm SHA256 `
+    -KeyLength 4096 `
+    -KeyUsage DigitalSignature
+
+if (-not $cert) {
+    Write-Error "Failed to create certificate."
+    exit 1
+}
+
+Write-Host "Certificate created: $($cert.Thumbprint)" -ForegroundColor Green
+
+# Export to PFX
+$securePassword = ConvertTo-SecureString -String $CertPassword -Force -AsPlainText
+$exportPath = Join-Path (Get-Location) $OutputFile
+
+Export-PfxCertificate -Cert $cert -FilePath $exportPath -Password $securePassword | Out-Null
+
+if (Test-Path $exportPath) {
+    Write-Host "Certificate exported to: $exportPath" -ForegroundColor Green
+    Write-Host ""
+    Write-Host "To build a signed release:" -ForegroundColor Yellow
+    Write-Host '  $env:CSC_LINK="code-signing-cert.pfx"' -ForegroundColor White
+    Write-Host "  `$env:CSC_KEY_PASSWORD=`"$CertPassword`"" -ForegroundColor White
+    Write-Host "  npm run build:win-signed" -ForegroundColor White
+    Write-Host ""
+    Write-Host "IMPORTANT: Add code-signing-cert.pfx to .gitignore!" -ForegroundColor Red
+} else {
+    Write-Error "Export failed."
+    exit 1
+}

scripts/download-tools.js

@@ -0,0 +1,148 @@
+#!/usr/bin/env node
+/**
+ * Downloads pandoc binary for the current build platform.
+ * Run automatically via `npm run download-tools` before building.
+ * Skips download if binary already exists (idempotent).
+ */
+
+const https = require('https');
+const http = require('http');
+const fs = require('fs');
+const path = require('path');
+const os = require('os');
+const { execSync } = require('child_process');
+
+const PANDOC_VERSION = '3.9.0.2';
+
+const PANDOC_CONFIG = {
+  linux: {
+    url: `https://github.com/jgm/pandoc/releases/download/${PANDOC_VERSION}/pandoc-${PANDOC_VERSION}-linux-amd64.tar.gz`,
+    archiveExt: '.tar.gz',
+    destFile: 'pandoc',
+    extract(archivePath, destDir) {
+      const tmpDir = path.join(os.tmpdir(), `pandoc-${Date.now()}`);
+      fs.mkdirSync(tmpDir, { recursive: true });
+      execSync(`tar -xzf "${archivePath}" -C "${tmpDir}" pandoc-${PANDOC_VERSION}/bin/pandoc`);
+      const src = path.join(tmpDir, `pandoc-${PANDOC_VERSION}`, 'bin', 'pandoc');
+      fs.copyFileSync(src, path.join(destDir, 'pandoc'));
+      fs.chmodSync(path.join(destDir, 'pandoc'), 0o755);
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    },
+  },
+  win32: {
+    url: `https://github.com/jgm/pandoc/releases/download/${PANDOC_VERSION}/pandoc-${PANDOC_VERSION}-windows-x86_64.zip`,
+    archiveExt: '.zip',
+    destFile: 'pandoc.exe',
+    extract(archivePath, destDir) {
+      const tmpDir = path.join(os.tmpdir(), `pandoc-${Date.now()}`);
+      fs.mkdirSync(tmpDir, { recursive: true });
+      execSync(
+        `powershell -Command "Expand-Archive -Force '${archivePath}' '${tmpDir}'"`,
+      );
+      const src = path.join(tmpDir, `pandoc-${PANDOC_VERSION}`, 'pandoc.exe');
+      fs.copyFileSync(src, path.join(destDir, 'pandoc.exe'));
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    },
+  },
+  darwin: {
+    url: `https://github.com/jgm/pandoc/releases/download/${PANDOC_VERSION}/pandoc-${PANDOC_VERSION}-x86_64-macOS.zip`,
+    archiveExt: '.zip',
+    destFile: 'pandoc',
+    extract(archivePath, destDir) {
+      const tmpDir = path.join(os.tmpdir(), `pandoc-${Date.now()}`);
+      fs.mkdirSync(tmpDir, { recursive: true });
+      execSync(`unzip -o "${archivePath}" -d "${tmpDir}"`);
+      const src = path.join(tmpDir, `pandoc-${PANDOC_VERSION}`, 'bin', 'pandoc');
+      fs.copyFileSync(src, path.join(destDir, 'pandoc'));
+      fs.chmodSync(path.join(destDir, 'pandoc'), 0o755);
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    },
+  },
+};
+
+function download(url, destPath) {
+  return new Promise((resolve, reject) => {
+    const file = fs.createWriteStream(destPath);
+    let received = 0;
+    let total = 0;
+    let lastPct = -1;
+
+    function get(redirectUrl) {
+      const client = redirectUrl.startsWith('https://') ? https : http;
+      client
+        .get(redirectUrl, (res) => {
+          if (res.statusCode === 301 || res.statusCode === 302) {
+            get(res.headers.location);
+            return;
+          }
+          if (res.statusCode !== 200) {
+            reject(new Error(`HTTP ${res.statusCode} for ${redirectUrl}`));
+            return;
+          }
+          total = parseInt(res.headers['content-length'] || '0', 10);
+          res.on('data', (chunk) => {
+            received += chunk.length;
+            if (total > 0) {
+              const pct = Math.floor((received / total) * 100);
+              if (pct !== lastPct && pct % 10 === 0) {
+                process.stdout.write(`  ${pct}%\r`);
+                lastPct = pct;
+              }
+            }
+          });
+          res.pipe(file);
+          file.on('finish', () => {
+            file.close();
+            process.stdout.write('  100%\n');
+            resolve();
+          });
+        })
+        .on('error', (err) => {
+          fs.unlink(destPath, () => {});
+          reject(err);
+        });
+    }
+    get(url);
+  });
+}
+
+async function downloadPandoc() {
+  const platform = process.platform;
+  const config = PANDOC_CONFIG[platform];
+
+  if (!config) {
+    console.log(`[download-tools] No pandoc config for platform "${platform}" — skipping.`);
+    return;
+  }
+
+  const destDir = path.join(__dirname, '..', 'bin', platform);
+  const destFile = path.join(destDir, config.destFile);
+
+  if (fs.existsSync(destFile)) {
+    console.log(`[download-tools] pandoc already present at ${destFile} — skipping.`);
+    return;
+  }
+
+  fs.mkdirSync(destDir, { recursive: true });
+
+  const tmpArchive = path.join(os.tmpdir(), `pandoc-download${config.archiveExt}`);
+
+  console.log(`[download-tools] Downloading pandoc ${PANDOC_VERSION} for ${platform}...`);
+  await download(config.url, tmpArchive);
+
+  console.log(`[download-tools] Extracting to ${destDir}...`);
+  config.extract(tmpArchive, destDir);
+
+  try {
+    fs.unlinkSync(tmpArchive);
+  } catch (_) {
+    /* ignore */
+  }
+
+  console.log(`[download-tools] pandoc ready: ${destFile}`);
+}
+
+downloadPandoc().catch((err) => {
+  console.error('[download-tools] FAILED:', err.message);
+  process.exit(1);
+});

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 4.1.0
+ * @version 4.4.1
  */
 
 /**
@@ -18,7 +18,7 @@ const electronFsAdapter = {
      * @returns {Promise<string>} File content
      */
     async readFile(path) {
-        return await window.electronAPI.readFile(path);
+        return await window.electronAPI.file.read(path);
     },
 
     /**
@@ -28,7 +28,7 @@ const electronFsAdapter = {
      * @returns {Promise<void>}
      */
     async writeFile(path, content) {
-        return await window.electronAPI.writeFile(path, content);
+        return await window.electronAPI.file.write(path, content);
     },
 
     /**
@@ -37,8 +37,7 @@ const electronFsAdapter = {
      * @returns {Promise<void>}
      */
     async deleteFile(path) {
-        // TODO: Add IPC channel for delete
-        throw new Error('deleteFile not implemented');
+        return await window.electronAPI.file.delete(path);
     },
 
     /**
@@ -47,8 +46,7 @@ const electronFsAdapter = {
      * @returns {Promise<void>}
      */
     async ensureDir(path) {
-        // TODO: Add IPC channel for ensureDir
-        throw new Error('ensureDir not implemented');
+        return await window.electronAPI.file.ensureDir(path);
     },
 
     /**
@@ -57,8 +55,18 @@ const electronFsAdapter = {
      * @returns {Promise<Array<import('../types').FileInfo>>}
      */
     async listDirectory(path) {
-        // TODO: Add IPC channel for listDirectory
-        throw new Error('listDirectory not implemented');
+        const result = await window.electronAPI.invoke('list-directory', path);
+        if (!result?.entries) {
+            return [];
+        }
+
+        return result.entries.map((entry) => ({
+            name: entry.name,
+            isDir: entry.isDirectory,
+            size: entry.size ?? 0,
+            modified: entry.modified ?? 0,
+            path: entry.path
+        }));
     },
 
     /**
@@ -67,8 +75,7 @@ const electronFsAdapter = {
      * @returns {Promise<boolean>}
      */
     async exists(path) {
-        // TODO: Add IPC channel for exists
-        throw new Error('exists not implemented');
+        return await window.electronAPI.file.exists(path);
     },
 
     /**
@@ -77,8 +84,7 @@ const electronFsAdapter = {
      * @returns {Promise<boolean>}
      */
     async isDirectory(path) {
-        // TODO: Add IPC channel for isDirectory
-        throw new Error('isDirectory not implemented');
+        return await window.electronAPI.file.isDirectory(path);
     },
 
     /**
@@ -88,8 +94,7 @@ const electronFsAdapter = {
      * @returns {Promise<void>}
      */
     async copy(source, dest) {
-        // TODO: Add IPC channel for copy
-        throw new Error('copy not implemented');
+        return await window.electronAPI.file.copy(source, dest);
     },
 
     /**
@@ -99,8 +104,7 @@ const electronFsAdapter = {
      * @returns {Promise<void>}
      */
     async move(source, dest) {
-        // TODO: Add IPC channel for move
-        throw new Error('move not implemented');
+        return await window.electronAPI.file.move(source, dest);
     }
 };
 

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 4.1.0
+ * @version 4.4.1
  */
 
 /**

src/analytics/analytics-panel.js

@@ -0,0 +1,112 @@
+/**
+ * Writing Analytics Panel — modal overlay displaying analytics dashboard
+ */
+
+const { analyze } = require('./writing-analytics');
+
+function showAnalyticsModal(tabManager) {
+    const existing = document.getElementById('analytics-modal');
+    if (existing) existing.remove();
+
+    const content = tabManager.getEditorContent();
+    const metrics = analyze(content);
+
+    const overlay = document.createElement('div');
+    overlay.id = 'analytics-modal';
+    overlay.className = 'analytics-overlay';
+
+    const maxCount = metrics.topWords.length > 0 ? metrics.topWords[0].count : 1;
+
+    overlay.innerHTML = `
+        <div class="analytics-modal">
+            <div class="analytics-header">
+                <h2>Writing Analytics</h2>
+                <button class="analytics-close" title="Close">&times;</button>
+            </div>
+            <div class="analytics-body">
+                <div class="analytics-section">
+                    <h3>Readability</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Flesch Reading Ease</span>
+                        <span class="analytics-value">${metrics.fleschEase}<small>${metrics.readabilityLabel}</small></span>
+                    </div>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Grade Level</span>
+                        <span class="analytics-value">${metrics.fleschGrade}</span>
+                    </div>
+                    <div class="readability-meter">
+                        <div class="readability-fill" style="width: ${Math.max(0, Math.min(100, metrics.fleschEase))}%"></div>
+                    </div>
+                </div>
+
+                <div class="analytics-section">
+                    <h3>Timing</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Reading Time</span>
+                        <span class="analytics-value">~${metrics.readingTime} min</span>
+                    </div>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Speaking Time</span>
+                        <span class="analytics-value">~${metrics.speakingTime} min</span>
+                    </div>
+                </div>
+
+                <div class="analytics-section">
+                    <h3>Structure</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Sentences</span>
+                        <span class="analytics-value">${metrics.sentenceCount} &bull; Paragraphs: ${metrics.paragraphCount}</span>
+                    </div>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Avg Sentence</span>
+                        <span class="analytics-value">${metrics.avgSentenceLength} words</span>
+                    </div>
+                    ${metrics.longestSentenceLength > 0 ? `
+                    <div class="analytics-row analytics-longest">
+                        <span class="analytics-label">Longest (${metrics.longestSentenceLength} words)</span>
+                        <span class="analytics-value analytics-sentence-preview">${escapeHtml(metrics.longestSentence)}</span>
+                    </div>` : ''}
+                </div>
+
+                <div class="analytics-section">
+                    <h3>Vocabulary</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Unique</span>
+                        <span class="analytics-value">${metrics.uniqueWordCount} / ${metrics.wordCount}<small>${metrics.lexicalDiversity}%</small></span>
+                    </div>
+                    ${metrics.topWords.length > 0 ? `
+                    <div class="word-cloud">
+                        ${metrics.topWords.map(w => {
+                            const scale = 13 + Math.round((w.count / maxCount) * 3);
+                            return `<span class="word-tag" style="font-size:${scale}px">${escapeHtml(w.word)}<small>${w.count}</small></span>`;
+                        }).join('')}
+                    </div>` : ''}
+                </div>
+            </div>
+        </div>
+    `;
+
+    const closeBtn = overlay.querySelector('.analytics-close');
+    closeBtn.addEventListener('click', () => overlay.remove());
+    overlay.addEventListener('click', (e) => {
+        if (e.target === overlay) overlay.remove();
+    });
+
+    const escHandler = (e) => {
+        if (e.key === 'Escape') {
+            overlay.remove();
+            document.removeEventListener('keydown', escHandler);
+        }
+    };
+    document.addEventListener('keydown', escHandler);
+
+    document.body.appendChild(overlay);
+}
+
+function escapeHtml(str) {
+    const div = document.createElement('div');
+    div.textContent = str;
+    return div.innerHTML;
+}
+
+module.exports = { showAnalyticsModal };

src/analytics/writing-analytics.js

@@ -0,0 +1,127 @@
+/**
+ * Writing Analytics — pure computation engine
+ * No DOM dependencies. Exported analyze(text) returns a metrics object.
+ */
+
+const STOP_WORDS = new Set([
+    'the', 'a', 'an', 'is', 'are', 'was', 'were', 'be', 'been',
+    'have', 'has', 'had', 'do', 'does', 'did', 'will', 'would',
+    'could', 'should', 'to', 'of', 'in', 'for', 'on', 'with',
+    'at', 'by', 'from', 'as', 'and', 'or', 'but', 'if', 'it',
+    'its', 'this', 'that', 'these', 'those', 'i', 'me', 'my',
+    'we', 'our', 'you', 'your', 'he', 'him', 'his', 'she', 'her',
+    'they', 'them', 'their', 'not', 'no', 'so', 'than', 'too',
+    'very', 'also', 'just', 'about', 'up', 'out', 'what', 'which', 'who'
+]);
+
+function countSyllables(word) {
+    word = word.toLowerCase().replace(/(?:[^laeiouy]es|ed|[^laeiouy]e)$/, '');
+    word = word.replace(/^y/, '');
+    return word.match(/[aeiouy]{1,2}/gi)?.length || 1;
+}
+
+function extractWords(text) {
+    return text.match(/[a-zA-Z]+(?:['-][a-zA-Z]+)*/g) || [];
+}
+
+function getReadabilityLabel(score) {
+    if (score >= 90) return 'Very Easy';
+    if (score >= 70) return 'Easy';
+    if (score >= 50) return 'Standard';
+    if (score >= 30) return 'Difficult';
+    return 'Very Difficult';
+}
+
+function analyze(text) {
+    if (!text || !text.trim()) {
+        return {
+            wordCount: 0,
+            sentenceCount: 0,
+            paragraphCount: 0,
+            fleschEase: 0,
+            fleschGrade: 0,
+            readabilityLabel: 'N/A',
+            readingTime: 0,
+            speakingTime: 0,
+            uniqueWordCount: 0,
+            lexicalDiversity: 0,
+            avgSentenceLength: 0,
+            longestSentence: '',
+            longestSentenceLength: 0,
+            topWords: []
+        };
+    }
+
+    const words = extractWords(text);
+    const wordCount = words.length;
+
+    const sentences = text.split(/[.!?]+/).map(s => s.trim()).filter(Boolean);
+    const sentenceCount = Math.max(sentences.length, 1);
+
+    const paragraphs = text.split(/\n\s*\n/).map(p => p.trim()).filter(Boolean);
+    const paragraphCount = Math.max(paragraphs.length, 1);
+
+    let totalSyllables = 0;
+    for (const w of words) {
+        totalSyllables += countSyllables(w);
+    }
+
+    const fleschEase = Math.round((206.835 - 1.015 * (wordCount / sentenceCount) - 84.6 * (totalSyllables / wordCount)) * 10) / 10;
+    const fleschGrade = Math.round((0.39 * (wordCount / sentenceCount) + 11.8 * (totalSyllables / wordCount) - 15.59) * 10) / 10;
+    const readabilityLabel = getReadabilityLabel(fleschEase);
+
+    const readingTime = Math.ceil(wordCount / 200);
+    const speakingTime = Math.ceil(wordCount / 130);
+
+    const uniqueWords = new Set(words.map(w => w.toLowerCase()));
+    const uniqueWordCount = uniqueWords.size;
+    const lexicalDiversity = wordCount > 0 ? Math.round((uniqueWordCount / wordCount) * 1000) / 10 : 0;
+
+    const avgSentenceLength = Math.round((wordCount / sentenceCount) * 10) / 10;
+
+    let longestSentence = '';
+    let longestSentenceLength = 0;
+    for (const s of sentences) {
+        const sWords = extractWords(s);
+        if (sWords.length > longestSentenceLength) {
+            longestSentenceLength = sWords.length;
+            longestSentence = s.trim();
+        }
+    }
+
+    if (longestSentence.length > 80) {
+        longestSentence = longestSentence.substring(0, 80) + '...';
+    }
+
+    const wordFreq = {};
+    for (const w of words) {
+        const lower = w.toLowerCase();
+        if (!STOP_WORDS.has(lower) && lower.length > 1) {
+            wordFreq[lower] = (wordFreq[lower] || 0) + 1;
+        }
+    }
+
+    const topWords = Object.entries(wordFreq)
+        .sort((a, b) => b[1] - a[1])
+        .slice(0, 10)
+        .map(([word, count]) => ({ word, count }));
+
+    return {
+        wordCount,
+        sentenceCount,
+        paragraphCount,
+        fleschEase,
+        fleschGrade,
+        readabilityLabel,
+        readingTime,
+        speakingTime,
+        uniqueWordCount,
+        lexicalDiversity,
+        avgSentenceLength,
+        longestSentence,
+        longestSentenceLength,
+        topWords
+    };
+}
+
+module.exports = { analyze };

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

@@ -4,7 +4,7 @@
     <meta charset="UTF-8">
     <!-- CSP: unsafe-inline/unsafe-eval required for marked.js extensions and Mermaid -->
     <!-- TODO: Migrate to nonce-based CSP for better security -->
-    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self' data:; connect-src 'self' https://www.plantuml.com;">
+    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net; style-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net; img-src 'self' data: blob:; font-src 'self' data: https://cdn.jsdelivr.net; connect-src 'self' https://www.plantuml.com;">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>MarkdownConverter</title>
     <!-- Design tokens - loaded first for CSS variable availability -->
@@ -15,7 +15,9 @@
     <link rel="stylesheet" href="styles-modern.css">
     <link rel="stylesheet" href="styles-concreteinfo.css">
     <link rel="stylesheet" href="styles-sidebar.css">
+    <link rel="stylesheet" href="styles-zen.css">
     <link rel="stylesheet" href="styles-welcome.css">
+    <link rel="stylesheet" href="styles-zen.css">
     <link rel="stylesheet" href="../node_modules/highlight.js/styles/default.css">
 </head>
 <body>
@@ -29,7 +31,7 @@
                 <span class="app-title">MarkdownConverter</span>
             </div>
             <div class="app-header-right">
-                <span class="app-version">v4.1.0</span>
+                <span class="app-version" id="app-version-display"></span>
             </div>
         </div>
         <div class="tab-bar" id="tab-bar" role="tablist" aria-label="Document tabs">
@@ -286,6 +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">
@@ -903,6 +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">
@@ -1273,6 +1322,8 @@
                         </div>
                     </div>
 
+                    <div id="pdf-status-message" class="info-message hidden" aria-live="polite"></div>
+
                     <!-- Progress indicator -->
                     <div id="pdf-progress" class="batch-progress hidden">
                         <div class="progress-bar">
@@ -1283,6 +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>
@@ -1437,6 +1498,16 @@
                             <line x1="9" y1="21" x2="9" y2="9"/>
                         </svg>
                     </button>
+                    <button class="sidebar-icon" data-panel="outline" title="Outline (Ctrl+Shift+O)">
+                        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                            <line x1="8" y1="6" x2="21" y2="6"/>
+                            <line x1="8" y1="12" x2="21" y2="12"/>
+                            <line x1="8" y1="18" x2="21" y2="18"/>
+                            <line x1="3" y1="6" x2="3.01" y2="6"/>
+                            <line x1="3" y1="12" x2="3.01" y2="12"/>
+                            <line x1="3" y1="18" x2="3.01" y2="18"/>
+                        </svg>
+                    </button>
                 </div>
                 <div class="sidebar-panel" id="sidebar-panel">
                     <div class="sidebar-panel-header">

src/main.js

@@ -2,8 +2,9 @@ const { app, BrowserWindow, Menu, dialog, ipcMain, shell } = require('electron')
 const path = require('path');
 const fs = require('fs');
 const { exec, execFile, spawn } = require('child_process');
-const { PDFDocument, rgb, degrees, StandardFonts } = require('pdf-lib');
 const WordTemplateExporter = require('./wordTemplateExporter');
+const PDFOperations = require('./main/PDFOperations');
+const GitOperations = require('./main/GitOperations');
 
 // Add MiKTeX to PATH for LaTeX support
 if (process.platform === 'win32') {
@@ -14,13 +15,39 @@ if (process.platform === 'win32') {
   }
 }
 
-// Get the system Pandoc path
+// Returns path to pandoc: bundled binary when packaged, dev bin or system fallback otherwise.
 function getPandocPath() {
-  // Pandoc is expected to be in the system's PATH.
-  // The command will be executed directly. Quoting is handled by exec.
+  if (app.isPackaged) {
+    const ext = process.platform === 'win32' ? '.exe' : '';
+    return path.join(process.resourcesPath, 'bin', `pandoc${ext}`);
+  }
+  // Development: prefer locally-downloaded binary in bin/<platform>/
+  const devBin = path.join(
+    __dirname,
+    '..',
+    'bin',
+    process.platform,
+    process.platform === 'win32' ? 'pandoc.exe' : 'pandoc',
+  );
+  if (fs.existsSync(devBin)) return devBin;
   return 'pandoc';
 }
 
+// Returns path to ffmpeg: asar-unpacked bundled binary when packaged, system fallback otherwise.
+function getFFmpegPath() {
+  try {
+    let ffmpegPath = require('ffmpeg-static');
+    if (app.isPackaged) {
+      // ffmpeg-static is in asarUnpack — rewrite the path to the unpacked location
+      ffmpegPath = ffmpegPath.replace('app.asar' + path.sep, 'app.asar.unpacked' + path.sep);
+    }
+    if (fs.existsSync(ffmpegPath)) return ffmpegPath;
+  } catch (_) {
+    /* ffmpeg-static not available */
+  }
+  return process.platform === 'win32' ? 'ffmpeg' : 'ffmpeg';
+}
+
 // Check if Pandoc is available
 function checkPandocAvailable() {
   return new Promise((resolve) => {
@@ -124,6 +151,35 @@ function validatePath(filePath) {
   return { valid: true, resolved };
 }
 
+/**
+ * Resolves a path for operations where the target may not exist yet.
+ * Validates string shape and blocks obviously sensitive locations.
+ * @param {string} filePath
+ * @returns {{ valid: boolean, resolved: string, error?: string }}
+ */
+function resolveWritablePath(filePath) {
+  if (!filePath || typeof filePath !== 'string') {
+    return { valid: false, resolved: '', error: 'Invalid path' };
+  }
+
+  let resolved;
+  try {
+    resolved = path.normalize(path.resolve(filePath));
+  } catch (err) {
+    return { valid: false, resolved: '', error: 'Invalid path format' };
+  }
+
+  if (resolved.includes('\0')) {
+    return { valid: false, resolved: '', error: 'Null byte in path' };
+  }
+
+  if (!isPathAccessible(resolved)) {
+    return { valid: false, resolved, error: 'Path is not accessible' };
+  }
+
+  return { valid: true, resolved };
+}
+
 /**
  * Checks if a resolved path is within allowed directories
  * For an editor app, we allow access to all user-accessible paths
@@ -186,7 +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);
 }
@@ -254,6 +312,41 @@ const store = {
   }
 };
 
+// Plugin settings IPC handlers
+ipcMain.handle('plugin-settings:get', (_event, key) => {
+  return store.get(key);
+});
+ipcMain.handle('plugin-settings:set', (_event, { key, value }) => {
+  store.set(key, value);
+});
+ipcMain.handle('get-app-version', () => app.getVersion());
+
+// ============================================
+// SECURITY: Permission Request Handler
+// ============================================
+// Restrict permissions to only those explicitly needed.
+// Deny: camera, microphone, geolocation, notifications, etc.
+// Allow: clipboard-read, clipboard-write (user expects these)
+app.on('web-contents-created', (event, contents) => {
+  contents.session.setPermissionRequestHandler((webContents, permission, callback) => {
+    const ALLOWED_PERMISSIONS = [
+      'clipboard-read',
+      'clipboard-write'
+    ];
+
+    if (ALLOWED_PERMISSIONS.includes(permission)) {
+      callback(true);
+    } else {
+      // Deny all other permissions (camera, microphone, geolocation, etc.)
+      console.warn(`[Security] Blocked permission request: ${permission}`);
+      callback(false);
+    }
+  });
+
+  // Disable file download dialogs for security
+  // contents.session.setDownloadPath(userDownloadsPath);
+});
+
 let mainWindow;
 let currentFile = null; // This will now represent the active tab's file
 let pandocAvailable = null; // Cache pandoc availability check
@@ -758,6 +851,20 @@ function createMenu() {
           }
         },
         { type: 'separator' },
+        {
+          label: 'Custom Preview CSS',
+          submenu: [
+            {
+              label: 'Load Custom Preview CSS...',
+              click: () => mainWindow.webContents.send('load-custom-css')
+            },
+            {
+              label: 'Clear Custom Preview CSS',
+              click: () => mainWindow.webContents.send('clear-custom-css')
+            }
+          ]
+        },
+        { type: 'separator' },
         { label: 'Reload', accelerator: 'CmdOrCtrl+R', role: 'reload' },
         { label: 'Toggle DevTools', accelerator: 'F12', role: 'toggleDevTools' },
         { type: 'separator' },
@@ -1000,7 +1107,7 @@ function showAboutDialog() {
 <body>
   <img src="${iconBase64}" class="logo" alt="MarkdownConverter">
   <h1>MarkdownConverter</h1>
-  <div class="version">Version 4.0.0</div>
+  <div class="version">Version ${app.getVersion()}</div>
 
   <div class="company">
     <span>by</span>
@@ -1804,9 +1911,12 @@ function checkConverterAvailable(tool) {
       case 'imagemagick':
         toolName = isWin ? 'magick' : 'convert';
         break;
-      case 'ffmpeg':
-        toolName = 'ffmpeg';
-        break;
+      case 'ffmpeg': {
+        // ffmpeg-static is always bundled — check it directly
+        const ffmpegBin = getFFmpegPath();
+        resolve(fs.existsSync(ffmpegBin) || ffmpegBin === 'ffmpeg');
+        return;
+      }
       default:
         resolve(false);
         return;
@@ -2033,8 +2143,8 @@ function convertWithImageMagick(inputFile, outputPath) {
 // FFmpeg conversion - returns {command, args} for execFile
 function convertWithFFmpeg(inputFile, outputPath) {
   return {
-    command: 'ffmpeg',
-    args: ['-i', inputFile, outputPath, '-y']
+    command: getFFmpegPath(),
+    args: ['-i', inputFile, outputPath, '-y'],
   };
 }
 
@@ -2203,8 +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`;
-      exportWithPandoc(pandocCmd, outputFile, format);
+      let revealCmd = `${getPandocPath()} "${currentFile}" -t revealjs -s -o "${outputFile}" --slide-level=2`;
+      if (options) {
+        if (options.revealTheme) revealCmd += ` -V theme="${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);
@@ -2793,9 +2927,13 @@ ipcMain.on('save-file', (event, { path, content }) => {
   currentFile = path;
 });
 
-ipcMain.on('save-current-file', (event, content) => {
-  if (currentFile) {
-    fs.writeFileSync(currentFile, content, 'utf-8');
+ipcMain.on('save-current-file', (event, payload) => {
+  const content = typeof payload === 'string' ? payload : payload?.content;
+  const targetFile = typeof payload === 'string' ? currentFile : payload?.filePath || currentFile;
+
+  if (targetFile) {
+    fs.writeFileSync(targetFile, content, 'utf-8');
+    currentFile = targetFile;
   } else {
     saveAsFile();
   }
@@ -2901,6 +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}`),
@@ -3661,7 +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) {
@@ -3671,6 +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');
@@ -3686,433 +3874,9 @@ function openFileFromPath(filePath) {
 }
 
 // ========================================
-// PDF EDITOR OPERATIONS (using pdf-lib)
+// PDF OPERATIONS — delegates to main/PDFOperations.js
 // ========================================
 
-// Helper function to parse page ranges (e.g., "1-5, 7, 9-12")
-function parsePageRanges(rangeString, totalPages) {
-  const pages = [];
-  const ranges = rangeString.split(',').map(r => r.trim());
-
-  for (const range of ranges) {
-    if (range.includes('-')) {
-      const [start, end] = range.split('-').map(n => parseInt(n.trim()));
-      for (let i = start; i <= end && i <= totalPages; i++) {
-        if (i > 0 && !pages.includes(i - 1)) { // Convert to 0-indexed
-          pages.push(i - 1);
-        }
-      }
-    } else {
-      const page = parseInt(range);
-      if (page > 0 && page <= totalPages && !pages.includes(page - 1)) {
-        pages.push(page - 1);
-      }
-    }
-  }
-
-  return pages.sort((a, b) => a - b);
-}
-
-// Helper function to convert hex color to RGB
-function hexToRgb(hex) {
-  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
-  return result ? {
-    r: parseInt(result[1], 16) / 255,
-    g: parseInt(result[2], 16) / 255,
-    b: parseInt(result[3], 16) / 255
-  } : { r: 0, g: 0, b: 0 };
-}
-
-// PDF Merge Operation
-async function pdfMerge(data) {
-  try {
-    const mergedPdf = await PDFDocument.create();
-
-    for (const filePath of data.inputFiles) {
-      const pdfBytes = fs.readFileSync(filePath);
-      const pdf = await PDFDocument.load(pdfBytes);
-      const copiedPages = await mergedPdf.copyPages(pdf, pdf.getPageIndices());
-      copiedPages.forEach(page => mergedPdf.addPage(page));
-    }
-
-    const pdfBytes = await mergedPdf.save();
-    fs.writeFileSync(data.outputPath, pdfBytes);
-
-    return { success: true, message: `Successfully merged ${data.inputFiles.length} PDFs` };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Split Operation
-async function pdfSplit(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    let splits = [];
-
-    if (data.splitMode === 'pages') {
-      // Split by page ranges
-      const ranges = data.pageRanges.split(',').map(r => r.trim());
-      for (let i = 0; i < ranges.length; i++) {
-        const range = ranges[i];
-        let pages = [];
-
-        if (range.includes('-')) {
-          const [start, end] = range.split('-').map(n => parseInt(n.trim()));
-          for (let p = start; p <= end && p <= totalPages; p++) {
-            pages.push(p - 1);
-          }
-        } else {
-          const page = parseInt(range);
-          if (page > 0 && page <= totalPages) {
-            pages.push(page - 1);
-          }
-        }
-
-        if (pages.length > 0) {
-          splits.push({ pages, name: `part_${i + 1}` });
-        }
-      }
-    } else if (data.splitMode === 'interval') {
-      // Split every N pages
-      const interval = data.interval;
-      for (let i = 0; i < totalPages; i += interval) {
-        const pages = [];
-        for (let j = i; j < i + interval && j < totalPages; j++) {
-          pages.push(j);
-        }
-        splits.push({ pages, name: `part_${Math.floor(i / interval) + 1}` });
-      }
-    } else if (data.splitMode === 'size') {
-      // Split by size (approximate - we'll split evenly)
-      // This is complex, so we'll do a simple even split for now
-      const maxSize = data.maxSize * 1024 * 1024; // Convert MB to bytes
-      // For simplicity, split into fixed page chunks
-      const chunkSize = Math.max(1, Math.floor(totalPages / 5)); // Split into ~5 parts
-      for (let i = 0; i < totalPages; i += chunkSize) {
-        const pages = [];
-        for (let j = i; j < i + chunkSize && j < totalPages; j++) {
-          pages.push(j);
-        }
-        splits.push({ pages, name: `part_${Math.floor(i / chunkSize) + 1}` });
-      }
-    }
-
-    // Create split PDFs
-    const baseName = path.basename(data.inputPath, '.pdf');
-    for (const split of splits) {
-      const newPdf = await PDFDocument.create();
-      const copiedPages = await newPdf.copyPages(pdf, split.pages);
-      copiedPages.forEach(page => newPdf.addPage(page));
-
-      const outputPath = path.join(data.outputFolder, `${baseName}_${split.name}.pdf`);
-      const newPdfBytes = await newPdf.save();
-      fs.writeFileSync(outputPath, newPdfBytes);
-    }
-
-    return { success: true, message: `Successfully split PDF into ${splits.length} files` };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Compress Operation
-async function pdfCompress(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-
-    // pdf-lib doesn't have built-in compression, but we can save with default compression
-    // For actual compression, we would need additional libraries like Ghostscript
-    // For now, we'll save with standard options which provides some compression
-    const compressedPdfBytes = await pdf.save({
-      useObjectStreams: true,
-      addDefaultPage: false,
-      objectsPerTick: 50
-    });
-
-    fs.writeFileSync(data.outputPath, compressedPdfBytes);
-
-    const originalSize = fs.statSync(data.inputPath).size;
-    const compressedSize = fs.statSync(data.outputPath).size;
-    const savings = ((originalSize - compressedSize) / originalSize * 100).toFixed(1);
-
-    return {
-      success: true,
-      message: `PDF compressed. Size reduced by ${savings}% (${(originalSize / 1024).toFixed(1)}KB → ${(compressedSize / 1024).toFixed(1)}KB)`
-    };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Rotate Pages Operation
-async function pdfRotate(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    let pagesToRotate = [];
-    if (data.pages && data.pages.trim()) {
-      pagesToRotate = parsePageRanges(data.pages, totalPages);
-    } else {
-      // Rotate all pages
-      pagesToRotate = Array.from({ length: totalPages }, (_, i) => i);
-    }
-
-    pagesToRotate.forEach(pageIndex => {
-      const page = pdf.getPage(pageIndex);
-      page.setRotation(degrees(data.angle));
-    });
-
-    const rotatedPdfBytes = await pdf.save();
-    fs.writeFileSync(data.outputPath, rotatedPdfBytes);
-
-    return {
-      success: true,
-      message: `Successfully rotated ${pagesToRotate.length} page(s) by ${data.angle}°`
-    };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Delete Pages Operation
-async function pdfDeletePages(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    const pagesToDelete = parsePageRanges(data.pages, totalPages);
-
-    // Remove pages in reverse order to maintain indices
-    pagesToDelete.sort((a, b) => b - a).forEach(pageIndex => {
-      pdf.removePage(pageIndex);
-    });
-
-    const newPdfBytes = await pdf.save();
-    fs.writeFileSync(data.outputPath, newPdfBytes);
-
-    return {
-      success: true,
-      message: `Successfully deleted ${pagesToDelete.length} page(s). New PDF has ${totalPages - pagesToDelete.length} pages`
-    };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Reorder Pages Operation
-async function pdfReorder(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    // Parse new page order
-    const newOrder = data.newOrder.split(',').map(n => parseInt(n.trim()) - 1); // Convert to 0-indexed
-
-    // Validate new order
-    if (newOrder.length !== totalPages) {
-      return { success: false, error: `New order must include all ${totalPages} pages` };
-    }
-
-    const newPdf = await PDFDocument.create();
-    const copiedPages = await newPdf.copyPages(pdf, newOrder);
-    copiedPages.forEach(page => newPdf.addPage(page));
-
-    const reorderedPdfBytes = await newPdf.save();
-    fs.writeFileSync(data.outputPath, reorderedPdfBytes);
-
-    return { success: true, message: 'Successfully reordered PDF pages' };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Watermark Operation
-async function pdfWatermark(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    // Determine which pages to watermark
-    let pagesToWatermark = [];
-    if (data.pages === 'all') {
-      pagesToWatermark = Array.from({ length: totalPages }, (_, i) => i);
-    } else if (data.pages === 'custom' && data.customPages) {
-      pagesToWatermark = parsePageRanges(data.customPages, totalPages);
-    }
-
-    const font = await pdf.embedFont(StandardFonts.Helvetica);
-    const color = hexToRgb(data.color);
-
-    for (const pageIndex of pagesToWatermark) {
-      const page = pdf.getPage(pageIndex);
-      const { width, height } = page.getSize();
-
-      let x, y, rotation = 0;
-
-      // Calculate position based on selected position
-      switch (data.position) {
-        case 'center':
-          x = width / 2;
-          y = height / 2;
-          break;
-        case 'diagonal':
-          x = width / 2;
-          y = height / 2;
-          rotation = 45;
-          break;
-        case 'top-left':
-          x = 50;
-          y = height - 50;
-          break;
-        case 'top-center':
-          x = width / 2;
-          y = height - 50;
-          break;
-        case 'top-right':
-          x = width - 50;
-          y = height - 50;
-          break;
-        case 'bottom-left':
-          x = 50;
-          y = 50;
-          break;
-        case 'bottom-center':
-          x = width / 2;
-          y = 50;
-          break;
-        case 'bottom-right':
-          x = width - 50;
-          y = 50;
-          break;
-        default:
-          x = width / 2;
-          y = height / 2;
-      }
-
-      page.drawText(data.text, {
-        x,
-        y,
-        size: data.fontSize,
-        font,
-        color: rgb(color.r, color.g, color.b),
-        opacity: data.opacity,
-        rotate: degrees(rotation)
-      });
-    }
-
-    const watermarkedPdfBytes = await pdf.save();
-    fs.writeFileSync(data.outputPath, watermarkedPdfBytes);
-
-    return {
-      success: true,
-      message: `Successfully added watermark to ${pagesToWatermark.length} page(s)`
-    };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Encrypt (Password Protection) Operation
-async function pdfEncrypt(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-
-    // pdf-lib has limited encryption support in v1.17.1
-    // We'll save with password (basic encryption)
-    const encryptedPdfBytes = await pdf.save({
-      userPassword: data.userPassword,
-      ownerPassword: data.ownerPassword || data.userPassword,
-      permissions: {
-        printing: data.permissions.printing ? 'highResolution' : 'lowResolution',
-        modifying: data.permissions.modifying,
-        copying: data.permissions.copying,
-        annotating: data.permissions.annotating,
-        fillingForms: data.permissions.fillingForms,
-        contentAccessibility: data.permissions.contentAccessibility,
-        documentAssembly: data.permissions.documentAssembly
-      }
-    });
-
-    fs.writeFileSync(data.outputPath, encryptedPdfBytes);
-
-    return { success: true, message: 'Successfully added password protection to PDF' };
-  } catch (error) {
-    // If pdf-lib doesn't support encryption in this version, provide a helpful error
-    if (error.message.includes('encrypt') || error.message.includes('password')) {
-      return {
-        success: false,
-        error: 'PDF encryption requires pdf-lib with encryption support. This feature may not be available in the current version.'
-      };
-    }
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Decrypt (Remove Password) Operation
-async function pdfDecrypt(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes, { password: data.password });
-
-    // Save without password
-    const decryptedPdfBytes = await pdf.save();
-    fs.writeFileSync(data.outputPath, decryptedPdfBytes);
-
-    return { success: true, message: 'Successfully removed password protection from PDF' };
-  } catch (error) {
-    if (error.message.includes('password') || error.message.includes('encrypted')) {
-      return { success: false, error: 'Incorrect password or PDF is not encrypted' };
-    }
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Permissions Operation
-async function pdfSetPermissions(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const loadOptions = data.currentPassword ? { password: data.currentPassword } : {};
-    const pdf = await PDFDocument.load(pdfBytes, loadOptions);
-
-    const newPdfBytes = await pdf.save({
-      ownerPassword: data.ownerPassword,
-      permissions: {
-        printing: data.permissions.printing ? 'highResolution' : 'lowResolution',
-        modifying: data.permissions.modifying,
-        copying: data.permissions.copying,
-        annotating: data.permissions.annotating,
-        fillingForms: data.permissions.fillingForms,
-        contentAccessibility: data.permissions.contentAccessibility,
-        documentAssembly: data.permissions.documentAssembly
-      }
-    });
-
-    fs.writeFileSync(data.outputPath, newPdfBytes);
-
-    return { success: true, message: 'Successfully updated PDF permissions' };
-  } catch (error) {
-    if (error.message.includes('encrypt') || error.message.includes('permission')) {
-      return {
-        success: false,
-        error: 'PDF permissions require pdf-lib with encryption support. This feature may not be available in the current version.'
-      };
-    }
-    return { success: false, error: error.message };
-  }
-}
-
-// IPC Handler for PDF Operations
 ipcMain.on('process-pdf-operation', async (event, data) => {
   try {
     mainWindow.webContents.send('pdf-operation-progress', {
@@ -4120,43 +3884,7 @@ ipcMain.on('process-pdf-operation', async (event, data) => {
       progress: 10
     });
 
-    let result;
-
-    switch (data.operation) {
-      case 'merge':
-        result = await pdfMerge(data);
-        break;
-      case 'split':
-        result = await pdfSplit(data);
-        break;
-      case 'compress':
-        result = await pdfCompress(data);
-        break;
-      case 'rotate':
-        result = await pdfRotate(data);
-        break;
-      case 'delete':
-        result = await pdfDeletePages(data);
-        break;
-      case 'reorder':
-        result = await pdfReorder(data);
-        break;
-      case 'watermark':
-        result = await pdfWatermark(data);
-        break;
-      case 'encrypt':
-        result = await pdfEncrypt(data);
-        break;
-      case 'decrypt':
-        result = await pdfDecrypt(data);
-        break;
-      case 'permissions':
-        result = await pdfSetPermissions(data);
-        break;
-      default:
-        result = { success: false, error: `Unknown operation: ${data.operation}` };
-    }
-
+    const result = await PDFOperations.executeOperation(data.operation, data);
     mainWindow.webContents.send('pdf-operation-complete', result);
   } catch (error) {
     mainWindow.webContents.send('pdf-operation-complete', {
@@ -4166,12 +3894,9 @@ ipcMain.on('process-pdf-operation', async (event, data) => {
   }
 });
 
-// IPC Handler for getting PDF page count
 ipcMain.on('get-pdf-page-count', async (event, filePath) => {
   try {
-    const pdfBytes = fs.readFileSync(filePath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const count = pdf.getPageCount();
+    const count = await PDFOperations.getPageCount(filePath);
     event.reply('pdf-page-count', { count });
   } catch (error) {
     event.reply('pdf-page-count', { error: error.message });
@@ -4344,6 +4069,8 @@ ipcMain.handle('list-directory', async (event, dirPath) => {
       .map(e => ({
         name: e.name,
         isDirectory: e.isDirectory(),
+        size: e.isDirectory() ? 0 : fs.statSync(path.join(validation.resolved, e.name)).size,
+        modified: fs.statSync(path.join(validation.resolved, e.name)).mtimeMs,
         path: path.join(validation.resolved, e.name)
       }));
     return { path: validation.resolved, entries };
@@ -4353,6 +4080,122 @@ 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)) {
+    throw new Error(validation.error || 'Invalid file path');
+  }
+
+  return fs.readFileSync(validation.resolved, 'utf-8');
+});
+
+ipcMain.handle('write-file', async (event, payload) => {
+  const validation = resolveWritablePath(payload?.path);
+  if (!validation.valid) {
+    throw new Error(validation.error || 'Invalid file path');
+  }
+
+  fs.mkdirSync(path.dirname(validation.resolved), { recursive: true });
+  fs.writeFileSync(validation.resolved, payload?.content ?? '', 'utf-8');
+  return { path: validation.resolved };
+});
+
+ipcMain.handle('delete-file', async (event, filePath) => {
+  const validation = validatePath(filePath);
+  if (!validation.valid || !isPathAccessible(validation.resolved)) {
+    throw new Error(validation.error || 'Invalid file path');
+  }
+
+  fs.rmSync(validation.resolved, { recursive: true, force: false });
+  return true;
+});
+
+ipcMain.handle('ensure-directory', async (event, dirPath) => {
+  const validation = resolveWritablePath(dirPath);
+  if (!validation.valid) {
+    throw new Error(validation.error || 'Invalid directory path');
+  }
+
+  fs.mkdirSync(validation.resolved, { recursive: true });
+  return validation.resolved;
+});
+
+ipcMain.handle('path-exists', async (event, filePath) => {
+  const validation = resolveWritablePath(filePath);
+  return validation.valid ? fs.existsSync(validation.resolved) : false;
+});
+
+ipcMain.handle('is-directory', async (event, filePath) => {
+  const validation = validatePath(filePath);
+  if (!validation.valid || !isPathAccessible(validation.resolved)) {
+    return false;
+  }
+
+  return fs.statSync(validation.resolved).isDirectory();
+});
+
+ipcMain.handle('copy-path', async (event, payload) => {
+  const sourceValidation = validatePath(payload?.source);
+  const destinationValidation = resolveWritablePath(payload?.destination);
+
+  if (!sourceValidation.valid || !isPathAccessible(sourceValidation.resolved)) {
+    throw new Error(sourceValidation.error || 'Invalid source path');
+  }
+  if (!destinationValidation.valid) {
+    throw new Error(destinationValidation.error || 'Invalid destination path');
+  }
+
+  fs.mkdirSync(path.dirname(destinationValidation.resolved), { recursive: true });
+  fs.cpSync(sourceValidation.resolved, destinationValidation.resolved, { recursive: true });
+  return { source: sourceValidation.resolved, destination: destinationValidation.resolved };
+});
+
+ipcMain.handle('move-path', async (event, payload) => {
+  const sourceValidation = validatePath(payload?.source);
+  const destinationValidation = resolveWritablePath(payload?.destination);
+
+  if (!sourceValidation.valid || !isPathAccessible(sourceValidation.resolved)) {
+    throw new Error(sourceValidation.error || 'Invalid source path');
+  }
+  if (!destinationValidation.valid) {
+    throw new Error(destinationValidation.error || 'Invalid destination path');
+  }
+
+  fs.mkdirSync(path.dirname(destinationValidation.resolved), { recursive: true });
+
+  try {
+    fs.renameSync(sourceValidation.resolved, destinationValidation.resolved);
+  } catch (error) {
+    if (error.code !== 'EXDEV') {
+      throw error;
+    }
+
+    fs.cpSync(sourceValidation.resolved, destinationValidation.resolved, { recursive: true });
+    fs.rmSync(sourceValidation.resolved, { recursive: true, force: false });
+  }
+
+  return { source: sourceValidation.resolved, destination: destinationValidation.resolved };
+});
+
 // Open a file by path (from explorer panel)
 ipcMain.on('open-file-path', (event, filePath) => {
   try {
@@ -4380,49 +4223,24 @@ ipcMain.on('open-file-path', (event, filePath) => {
 // ============================================
 // Git IPC Handlers
 // ============================================
-const simpleGit = require('simple-git');
-
-function getGitRepo() {
-  // Use the directory of the current file, or the app's working directory
-  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
-  return simpleGit(dir);
-}
-
 ipcMain.handle('git-status', async () => {
-  try {
-    const git = getGitRepo();
-    return await git.status();
-  } catch (err) {
-    return { error: 'Not a git repository' };
-  }
+  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
+  return GitOperations.getStatus(dir);
 });
 
 ipcMain.handle('git-stage', async (event, { files }) => {
-  try {
-    const git = getGitRepo();
-    await git.add(files);
-    return await git.status();
-  } catch (err) {
-    return { error: err.message };
-  }
+  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
+  return GitOperations.stage(dir, files);
 });
 
 ipcMain.handle('git-commit', async (event, { message }) => {
-  try {
-    const git = getGitRepo();
-    return await git.commit(message);
-  } catch (err) {
-    return { error: err.message };
-  }
+  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
+  return GitOperations.commit(dir, message);
 });
 
 ipcMain.handle('git-log', async () => {
-  try {
-    const git = getGitRepo();
-    return await git.log({ maxCount: 20 });
-  } catch (err) {
-    return { error: err.message };
-  }
+  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
+  return GitOperations.log(dir);
 });
 
 // ============================================

src/main/GitOperations.js

@@ -0,0 +1,44 @@
+const simpleGit = require('simple-git');
+
+function getGitInstance(dir) {
+  return simpleGit(dir);
+}
+
+async function getStatus(dir) {
+  try {
+    const git = getGitInstance(dir);
+    return await git.status();
+  } catch (err) {
+    return { error: 'Not a git repository' };
+  }
+}
+
+async function stage(dir, files) {
+  try {
+    const git = getGitInstance(dir);
+    await git.add(files);
+    return await git.status();
+  } catch (err) {
+    return { error: err.message };
+  }
+}
+
+async function commit(dir, message) {
+  try {
+    const git = getGitInstance(dir);
+    return await git.commit(message);
+  } catch (err) {
+    return { error: err.message };
+  }
+}
+
+async function log(dir, maxCount = 20) {
+  try {
+    const git = getGitInstance(dir);
+    return await git.log({ maxCount });
+  } catch (err) {
+    return { error: err.message };
+  }
+}
+
+module.exports = { getStatus, stage, commit, log };

src/main/PDFOperations.js

@@ -0,0 +1,433 @@
+const fs = require('fs');
+const path = require('path');
+const { PDFDocument, rgb, degrees, StandardFonts } = require('pdf-lib');
+
+function parsePageRanges(rangeString, totalPages) {
+  const pages = [];
+  const ranges = rangeString.split(',').map(r => r.trim());
+
+  for (const range of ranges) {
+    if (range.includes('-')) {
+      const [start, end] = range.split('-').map(n => parseInt(n.trim()));
+      for (let i = start; i <= end && i <= totalPages; i++) {
+        if (i > 0 && !pages.includes(i - 1)) {
+          pages.push(i - 1);
+        }
+      }
+    } else {
+      const page = parseInt(range);
+      if (page > 0 && page <= totalPages && !pages.includes(page - 1)) {
+        pages.push(page - 1);
+      }
+    }
+  }
+
+  return pages.sort((a, b) => a - b);
+}
+
+function hexToRgb(hex) {
+  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
+  return result ? {
+    r: parseInt(result[1], 16) / 255,
+    g: parseInt(result[2], 16) / 255,
+    b: parseInt(result[3], 16) / 255
+  } : { r: 0, g: 0, b: 0 };
+}
+
+async function pdfMerge(data) {
+  try {
+    const mergedPdf = await PDFDocument.create();
+
+    for (const filePath of data.inputFiles) {
+      const pdfBytes = fs.readFileSync(filePath);
+      const pdf = await PDFDocument.load(pdfBytes);
+      const copiedPages = await mergedPdf.copyPages(pdf, pdf.getPageIndices());
+      copiedPages.forEach(page => mergedPdf.addPage(page));
+    }
+
+    const pdfBytes = await mergedPdf.save();
+    fs.writeFileSync(data.outputPath, pdfBytes);
+
+    return { success: true, message: `Successfully merged ${data.inputFiles.length} PDFs` };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfSplit(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    const splits = [];
+
+    if (data.splitMode === 'pages') {
+      const ranges = data.pageRanges.split(',').map(r => r.trim());
+      for (let i = 0; i < ranges.length; i++) {
+        const range = ranges[i];
+        const pages = [];
+
+        if (range.includes('-')) {
+          const [start, end] = range.split('-').map(n => parseInt(n.trim()));
+          for (let p = start; p <= end && p <= totalPages; p++) {
+            pages.push(p - 1);
+          }
+        } else {
+          const page = parseInt(range);
+          if (page > 0 && page <= totalPages) {
+            pages.push(page - 1);
+          }
+        }
+
+        if (pages.length > 0) {
+          splits.push({ pages, name: `part_${i + 1}` });
+        }
+      }
+    } else if (data.splitMode === 'interval') {
+      const interval = data.interval;
+      for (let i = 0; i < totalPages; i += interval) {
+        const pages = [];
+        for (let j = i; j < i + interval && j < totalPages; j++) {
+          pages.push(j);
+        }
+        splits.push({ pages, name: `part_${Math.floor(i / interval) + 1}` });
+      }
+    } else if (data.splitMode === 'size') {
+      const chunkSize = Math.max(1, Math.floor(totalPages / 5));
+      for (let i = 0; i < totalPages; i += chunkSize) {
+        const pages = [];
+        for (let j = i; j < i + chunkSize && j < totalPages; j++) {
+          pages.push(j);
+        }
+        splits.push({ pages, name: `part_${Math.floor(i / chunkSize) + 1}` });
+      }
+    }
+
+    const baseName = path.basename(data.inputPath, '.pdf');
+    for (const split of splits) {
+      const newPdf = await PDFDocument.create();
+      const copiedPages = await newPdf.copyPages(pdf, split.pages);
+      copiedPages.forEach(page => newPdf.addPage(page));
+
+      const outputPath = path.join(data.outputFolder, `${baseName}_${split.name}.pdf`);
+      const newPdfBytes = await newPdf.save();
+      fs.writeFileSync(outputPath, newPdfBytes);
+    }
+
+    return { success: true, message: `Successfully split PDF into ${splits.length} files` };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfCompress(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+
+    const compressedPdfBytes = await pdf.save({
+      useObjectStreams: true,
+      addDefaultPage: false,
+      objectsPerTick: 50
+    });
+
+    fs.writeFileSync(data.outputPath, compressedPdfBytes);
+
+    const originalSize = fs.statSync(data.inputPath).size;
+    const compressedSize = fs.statSync(data.outputPath).size;
+    const savings = ((originalSize - compressedSize) / originalSize * 100).toFixed(1);
+
+    return {
+      success: true,
+      message: `PDF compressed. Size reduced by ${savings}% (${(originalSize / 1024).toFixed(1)}KB → ${(compressedSize / 1024).toFixed(1)}KB)`
+    };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfRotate(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    let pagesToRotate = [];
+    if (data.pages && data.pages.trim()) {
+      pagesToRotate = parsePageRanges(data.pages, totalPages);
+    } else {
+      pagesToRotate = Array.from({ length: totalPages }, (_, i) => i);
+    }
+
+    pagesToRotate.forEach(pageIndex => {
+      const page = pdf.getPage(pageIndex);
+      page.setRotation(degrees(data.angle));
+    });
+
+    const rotatedPdfBytes = await pdf.save();
+    fs.writeFileSync(data.outputPath, rotatedPdfBytes);
+
+    return {
+      success: true,
+      message: `Successfully rotated ${pagesToRotate.length} page(s) by ${data.angle}\u00B0`
+    };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfDeletePages(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    const pagesToDelete = parsePageRanges(data.pages, totalPages);
+
+    pagesToDelete.sort((a, b) => b - a).forEach(pageIndex => {
+      pdf.removePage(pageIndex);
+    });
+
+    const newPdfBytes = await pdf.save();
+    fs.writeFileSync(data.outputPath, newPdfBytes);
+
+    return {
+      success: true,
+      message: `Successfully deleted ${pagesToDelete.length} page(s). New PDF has ${totalPages - pagesToDelete.length} pages`
+    };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfReorder(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    const newOrder = data.newOrder.split(',').map(n => parseInt(n.trim()) - 1);
+
+    if (newOrder.length !== totalPages) {
+      return { success: false, error: `New order must include all ${totalPages} pages` };
+    }
+
+    const newPdf = await PDFDocument.create();
+    const copiedPages = await newPdf.copyPages(pdf, newOrder);
+    copiedPages.forEach(page => newPdf.addPage(page));
+
+    const reorderedPdfBytes = await newPdf.save();
+    fs.writeFileSync(data.outputPath, reorderedPdfBytes);
+
+    return { success: true, message: 'Successfully reordered PDF pages' };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfWatermark(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    let pagesToWatermark = [];
+    if (data.pages === 'all') {
+      pagesToWatermark = Array.from({ length: totalPages }, (_, i) => i);
+    } else if (data.pages === 'custom' && data.customPages) {
+      pagesToWatermark = parsePageRanges(data.customPages, totalPages);
+    }
+
+    const font = await pdf.embedFont(StandardFonts.Helvetica);
+    const color = hexToRgb(data.color);
+
+    for (const pageIndex of pagesToWatermark) {
+      const page = pdf.getPage(pageIndex);
+      const { width, height } = page.getSize();
+
+      let x, y, rotation = 0;
+
+      switch (data.position) {
+        case 'center':
+          x = width / 2;
+          y = height / 2;
+          break;
+        case 'diagonal':
+          x = width / 2;
+          y = height / 2;
+          rotation = 45;
+          break;
+        case 'top-left':
+          x = 50;
+          y = height - 50;
+          break;
+        case 'top-center':
+          x = width / 2;
+          y = height - 50;
+          break;
+        case 'top-right':
+          x = width - 50;
+          y = height - 50;
+          break;
+        case 'bottom-left':
+          x = 50;
+          y = 50;
+          break;
+        case 'bottom-center':
+          x = width / 2;
+          y = 50;
+          break;
+        case 'bottom-right':
+          x = width - 50;
+          y = 50;
+          break;
+        default:
+          x = width / 2;
+          y = height / 2;
+      }
+
+      page.drawText(data.text, {
+        x,
+        y,
+        size: data.fontSize,
+        font,
+        color: rgb(color.r, color.g, color.b),
+        opacity: data.opacity,
+        rotate: degrees(rotation)
+      });
+    }
+
+    const watermarkedPdfBytes = await pdf.save();
+    fs.writeFileSync(data.outputPath, watermarkedPdfBytes);
+
+    return {
+      success: true,
+      message: `Successfully added watermark to ${pagesToWatermark.length} page(s)`
+    };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfEncrypt(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+
+    const encryptedPdfBytes = await pdf.save({
+      userPassword: data.userPassword,
+      ownerPassword: data.ownerPassword || data.userPassword,
+      permissions: {
+        printing: data.permissions.printing ? 'highResolution' : 'lowResolution',
+        modifying: data.permissions.modifying,
+        copying: data.permissions.copying,
+        annotating: data.permissions.annotating,
+        fillingForms: data.permissions.fillingForms,
+        contentAccessibility: data.permissions.contentAccessibility,
+        documentAssembly: data.permissions.documentAssembly
+      }
+    });
+
+    fs.writeFileSync(data.outputPath, encryptedPdfBytes);
+
+    return { success: true, message: 'Successfully added password protection to PDF' };
+  } catch (error) {
+    if (error.message.includes('encrypt') || error.message.includes('password')) {
+      return {
+        success: false,
+        error: 'PDF encryption requires pdf-lib with encryption support. This feature may not be available in the current version.'
+      };
+    }
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfDecrypt(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes, { password: data.password });
+
+    const decryptedPdfBytes = await pdf.save();
+    fs.writeFileSync(data.outputPath, decryptedPdfBytes);
+
+    return { success: true, message: 'Successfully removed password protection from PDF' };
+  } catch (error) {
+    if (error.message.includes('password') || error.message.includes('encrypted')) {
+      return { success: false, error: 'Incorrect password or PDF is not encrypted' };
+    }
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfSetPermissions(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const loadOptions = data.currentPassword ? { password: data.currentPassword } : {};
+    const pdf = await PDFDocument.load(pdfBytes, loadOptions);
+
+    const newPdfBytes = await pdf.save({
+      ownerPassword: data.ownerPassword,
+      permissions: {
+        printing: data.permissions.printing ? 'highResolution' : 'lowResolution',
+        modifying: data.permissions.modifying,
+        copying: data.permissions.copying,
+        annotating: data.permissions.annotating,
+        fillingForms: data.permissions.fillingForms,
+        contentAccessibility: data.permissions.contentAccessibility,
+        documentAssembly: data.permissions.documentAssembly
+      }
+    });
+
+    fs.writeFileSync(data.outputPath, newPdfBytes);
+
+    return { success: true, message: 'Successfully updated PDF permissions' };
+  } catch (error) {
+    if (error.message.includes('encrypt') || error.message.includes('permission')) {
+      return {
+        success: false,
+        error: 'PDF permissions require pdf-lib with encryption support. This feature may not be available in the current version.'
+      };
+    }
+    return { success: false, error: error.message };
+  }
+}
+
+function executeOperation(operation, data) {
+  switch (operation) {
+    case 'merge': return pdfMerge(data);
+    case 'split': return pdfSplit(data);
+    case 'compress': return pdfCompress(data);
+    case 'rotate': return pdfRotate(data);
+    case 'delete': return pdfDeletePages(data);
+    case 'reorder': return pdfReorder(data);
+    case 'watermark': return pdfWatermark(data);
+    case 'encrypt': return pdfEncrypt(data);
+    case 'decrypt': return pdfDecrypt(data);
+    case 'permissions': return pdfSetPermissions(data);
+    default: return Promise.resolve({ success: false, error: `Unknown operation: ${operation}` });
+  }
+}
+
+async function getPageCount(filePath) {
+  const pdfBytes = fs.readFileSync(filePath);
+  const pdf = await PDFDocument.load(pdfBytes);
+  return pdf.getPageCount();
+}
+
+module.exports = {
+  parsePageRanges,
+  hexToRgb,
+  pdfMerge,
+  pdfSplit,
+  pdfCompress,
+  pdfRotate,
+  pdfDeletePages,
+  pdfReorder,
+  pdfWatermark,
+  pdfEncrypt,
+  pdfDecrypt,
+  pdfSetPermissions,
+  executeOperation,
+  getPageCount
+};

src/plugins/built-in/_sample/index.js

@@ -0,0 +1,12 @@
+const { PluginAPI } = require('../../plugin-api');
+
+class SamplePlugin extends PluginAPI {
+  init(context) {
+    this.context = context;
+    context.commands.register('hello', 'Sample: Hello World', () => {
+      console.log('[SamplePlugin] Hello from the plugin system!');
+    });
+  }
+}
+
+module.exports = { Plugin: SamplePlugin };

src/plugins/built-in/_sample/manifest.json

@@ -0,0 +1,13 @@
+{
+  "id": "_sample",
+  "name": "Sample Plugin",
+  "version": "1.0.0",
+  "description": "Demonstrates the plugin system. Safe to delete.",
+  "icon": "puzzle",
+  "extensionPoints": {
+    "commands": [
+      { "id": "hello", "label": "Sample: Hello World", "shortcut": "" }
+    ]
+  },
+  "settings": []
+}

src/plugins/built-in/writing-studio/goal-tracker.js

@@ -0,0 +1,87 @@
+const HISTORY_KEY = 'plugins.writing-studio.history';
+
+class GoalTracker {
+  /**
+   * @param {object} store - { get(key), set(key, value) } settings backend
+   */
+  constructor(store) {
+    this.store = store;
+  }
+
+  _getHistory() {
+    const raw = this.store.get(HISTORY_KEY);
+    return raw ? JSON.parse(raw) : {};
+  }
+
+  _setHistory(history) {
+    this.store.set(HISTORY_KEY, JSON.stringify(history));
+  }
+
+  _setHistoryDay(dateStr, data) {
+    const history = this._getHistory();
+    history[dateStr] = data;
+    this._setHistory(history);
+  }
+
+  addWords(count) {
+    const today = new Date().toISOString().split('T')[0];
+    const history = this._getHistory();
+    if (!history[today]) {
+      history[today] = { words: 0, sessions: 0 };
+    }
+    history[today].words += count;
+    history[today].sessions += 1;
+    this._setHistory(history);
+  }
+
+  getDailyProgress(goal) {
+    const today = new Date().toISOString().split('T')[0];
+    const history = this._getHistory();
+    const written = history[today]?.words || 0;
+    return { written, goal, pct: goal > 0 ? Math.min(100, Math.round((written / goal) * 100)) : 0 };
+  }
+
+  getStreak(goal) {
+    const history = this._getHistory();
+    let streak = 0;
+    const d = new Date();
+    for (let i = 0; i < 365; i++) {
+      const key = d.toISOString().split('T')[0];
+      const day = history[key];
+      if (day && day.words >= goal) {
+        streak++;
+        d.setDate(d.getDate() - 1);
+      } else {
+        break;
+      }
+    }
+    return streak;
+  }
+
+  getLast30Days() {
+    const history = this._getHistory();
+    const days = [];
+    const d = new Date();
+    for (let i = 0; i < 30; i++) {
+      const key = d.toISOString().split('T')[0];
+      const day = history[key];
+      days.push({ date: key, words: day?.words || 0 });
+      d.setDate(d.getDate() - 1);
+    }
+    return days.reverse();
+  }
+
+  getWeeklyTotal() {
+    const history = this._getHistory();
+    let total = 0;
+    const d = new Date();
+    for (let i = 0; i < 7; i++) {
+      const key = d.toISOString().split('T')[0];
+      if (history[key]) total += history[key].words || 0;
+      d.setDate(d.getDate() - 1);
+    }
+    return total;
+  }
+}
+
+module.exports = { GoalTracker };

src/plugins/built-in/writing-studio/index.js

@@ -0,0 +1,102 @@
+const { PluginAPI } = require('../../../plugins/plugin-api');
+const { SprintEngine } = require('./sprint-engine');
+const { GoalTracker } = require('./goal-tracker');
+const { SnapshotManager } = require('./snapshot-manager');
+const { ProjectManager } = require('./project-manager');
+
+class WritingStudioPlugin extends PluginAPI {
+  init(context) {
+    this.context = context;
+
+    this.sprintEngine = new SprintEngine({
+      onEvent: (name, data) => context.events.emit(name, data)
+    });
+    this.goalTracker = new GoalTracker(context.settings);
+    this.snapshotManager = new SnapshotManager(context.settings);
+    this.projectManager = new ProjectManager({
+      readFile: (p) => context.ipc.invoke('read-file', p),
+      writeFile: (p, c) => context.ipc.invoke('write-file', p, c),
+      fileExists: (p) => context.ipc.invoke('path-exists', p),
+      listDir: (p) => context.ipc.invoke('list-directory', p)
+    });
+
+    this._engines = {
+      sprint: this.sprintEngine,
+      goals: this.goalTracker,
+      snapshots: this.snapshotManager,
+      projects: this.projectManager
+    };
+
+    this._registerCommands(context);
+    this._registerStatusBar(context);
+  }
+
+  _registerCommands(context) {
+    const { sprintEngine, snapshotManager, goalTracker } = this;
+
+    context.commands.register('start-sprint', 'Studio: Start Sprint', () => {
+      const duration = context.settings.get('sprintDuration') || 25;
+      const content = context.editor.getContent() || '';
+      const words = content.split(/\s+/).filter(Boolean).length;
+      sprintEngine.start(duration, words);
+    }, 'Ctrl+Alt+S');
+
+    context.commands.register('stop-sprint', 'Studio: Stop Sprint', () => {
+      if (!sprintEngine.isActive()) return;
+      const content = context.editor.getContent() || '';
+      const words = content.split(/\s+/).filter(Boolean).length;
+      const result = sprintEngine.stop(words);
+      goalTracker.addWords(result.wordDelta);
+      context.events.emit('sprint:stopped', result);
+    }, 'Ctrl+Alt+Shift+S');
+
+    context.commands.register('take-snapshot', 'Studio: Take Snapshot', () => {
+      const content = context.editor.getContent() || '';
+      snapshotManager.create(content, 'manual');
+      context.events.emit('snapshot:created', {});
+    }, 'Ctrl+Alt+N');
+
+    context.commands.register('restore-last-snapshot', 'Studio: Restore Last Snapshot', () => {
+      const snaps = snapshotManager.list();
+      if (snaps.length === 0) return;
+      const content = snapshotManager.restore(snaps[0].id);
+      context.editor.insertAtCursor(content);
+    }, 'Ctrl+Alt+Z');
+
+    context.commands.register('new-project', 'Studio: New Project', () => {
+      context.events.emit('studio:new-project', {});
+    });
+
+    context.commands.register('compile-manuscript', 'Studio: Compile Manuscript', () => {
+      context.events.emit('studio:compile', {});
+    }, 'Ctrl+Alt+E');
+
+    context.commands.register('proofread-document', 'Studio: Proofread Document', () => {
+      if (context.events.hasHandler('ai:analyze')) {
+        const content = context.editor.getContent() || '';
+        context.events.emit('ai:analyze', { text: content, type: 'grammar' });
+      }
+    }, 'Ctrl+Alt+G');
+  }
+
+  _registerStatusBar(context) {
+    context.statusBar.registerIndicator('word-goal', {
+      text: '0/1000',
+      tooltip: 'Daily word goal progress'
+    });
+    context.statusBar.registerIndicator('sprint-timer', {
+      text: '',
+      tooltip: 'Writing sprint timer'
+    });
+  }
+
+  deactivate() {
+    if (this._sprintInterval) clearInterval(this._sprintInterval);
+  }
+
+  getEngines() {
+    return this._engines;
+  }
+}
+
+module.exports = { Plugin: WritingStudioPlugin };

src/plugins/built-in/writing-studio/manifest.json

@@ -0,0 +1,31 @@
+{
+  "id": "writing-studio",
+  "name": "Writing Studio",
+  "version": "1.0.0",
+  "description": "Manuscript management, writing sprints, goal tracking, snapshots, and smart proofreading",
+  "icon": "pen-tool",
+  "extensionPoints": {
+    "sidebar": [
+      { "id": "manuscript", "title": "Manuscript", "order": 30 },
+      { "id": "goals", "title": "Goals", "order": 31 },
+      { "id": "snapshots", "title": "Snapshots", "order": 32 },
+      { "id": "proofread", "title": "Proofread", "order": 33 }
+    ],
+    "commands": [
+      { "id": "start-sprint", "label": "Studio: Start Sprint", "shortcut": "Ctrl+Alt+S" },
+      { "id": "stop-sprint", "label": "Studio: Stop Sprint", "shortcut": "Ctrl+Alt+Shift+S" },
+      { "id": "take-snapshot", "label": "Studio: Take Snapshot", "shortcut": "Ctrl+Alt+N" },
+      { "id": "restore-last-snapshot", "label": "Studio: Restore Last Snapshot", "shortcut": "Ctrl+Alt+Z" },
+      { "id": "new-project", "label": "Studio: New Project", "shortcut": "" },
+      { "id": "compile-manuscript", "label": "Studio: Compile Manuscript", "shortcut": "Ctrl+Alt+E" },
+      { "id": "proofread-document", "label": "Studio: Proofread Document", "shortcut": "Ctrl+Alt+G" }
+    ],
+    "statusBar": { "indicators": ["sprint-timer", "word-goal"] }
+  },
+  "settings": [
+    { "key": "dailyGoal", "type": "number", "default": 1000, "label": "Daily word goal" },
+    { "key": "sprintDuration", "type": "number", "default": 25, "label": "Sprint duration (min)" },
+    { "key": "autoSnapshotInterval", "type": "number", "default": 0, "label": "Auto-snapshot interval (min, 0=off)" },
+    { "key": "maxSnapshots", "type": "number", "default": 50, "label": "Max snapshots to keep" }
+  ]
+}

src/plugins/built-in/writing-studio/panels/goals-panel.js

@@ -0,0 +1,99 @@
+function renderGoalsPanel(container, { engines, settings }) {
+  const dailyGoal = settings.get('dailyGoal') || 1000;
+  const progress = engines.goals.getDailyProgress(dailyGoal);
+  const streak = engines.goals.getStreak(dailyGoal);
+  const weekly = engines.goals.getWeeklyTotal();
+  const last30 = engines.goals.getLast30Days();
+
+  container.replaceChildren();
+
+  const panel = document.createElement('div');
+  panel.className = 'ws-panel';
+
+  // Daily progress section
+  const section1 = document.createElement('div');
+  section1.className = 'ws-section';
+  const heading1 = document.createElement('h3');
+  heading1.className = 'ws-heading';
+  heading1.textContent = 'Daily Progress';
+  section1.appendChild(heading1);
+
+  const bar = document.createElement('div');
+  bar.className = 'ws-progress-bar';
+  const fill = document.createElement('div');
+  fill.className = 'ws-progress-fill';
+  fill.style.width = progress.pct + '%';
+  bar.appendChild(fill);
+  section1.appendChild(bar);
+
+  const row = document.createElement('div');
+  row.className = 'ws-stat-row';
+  const label = document.createElement('span');
+  label.textContent = progress.written.toLocaleString() + ' / ' + dailyGoal.toLocaleString() + ' words';
+  const pct = document.createElement('span');
+  pct.className = 'ws-pct';
+  pct.textContent = progress.pct + '%';
+  row.appendChild(label);
+  row.appendChild(pct);
+  section1.appendChild(row);
+  panel.appendChild(section1);
+
+  // Stats cards
+  const section2 = document.createElement('div');
+  section2.className = 'ws-section';
+  const grid = document.createElement('div');
+  grid.className = 'ws-stat-grid';
+
+  const streakCard = document.createElement('div');
+  streakCard.className = 'ws-stat-card';
+  const streakVal = document.createElement('span');
+  streakVal.className = 'ws-stat-value';
+  streakVal.textContent = String(streak);
+  const streakLbl = document.createElement('span');
+  streakLbl.className = 'ws-stat-label';
+  streakLbl.textContent = 'Day Streak';
+  streakCard.appendChild(streakVal);
+  streakCard.appendChild(streakLbl);
+
+  const weekCard = document.createElement('div');
+  weekCard.className = 'ws-stat-card';
+  const weekVal = document.createElement('span');
+  weekVal.className = 'ws-stat-value';
+  weekVal.textContent = weekly.toLocaleString();
+  const weekLbl = document.createElement('span');
+  weekLbl.className = 'ws-stat-label';
+  weekLbl.textContent = 'This Week';
+  weekCard.appendChild(weekVal);
+  weekCard.appendChild(weekLbl);
+
+  grid.appendChild(streakCard);
+  grid.appendChild(weekCard);
+  section2.appendChild(grid);
+  panel.appendChild(section2);
+
+  // 30-day chart
+  const section3 = document.createElement('div');
+  section3.className = 'ws-section';
+  const heading3 = document.createElement('h3');
+  heading3.className = 'ws-heading';
+  heading3.textContent = 'Last 30 Days';
+  section3.appendChild(heading3);
+
+  const chart = document.createElement('div');
+  chart.className = 'ws-chart';
+  const maxWords = Math.max(...last30.map(d => d.words), 1);
+  for (const day of last30) {
+    const barEl = document.createElement('div');
+    const height = Math.max(2, (day.words / maxWords) * 60);
+    barEl.className = 'ws-bar' + (day.words >= dailyGoal ? ' ws-bar-met' : '');
+    barEl.style.height = height + 'px';
+    barEl.title = day.date + ': ' + day.words + ' words';
+    chart.appendChild(barEl);
+  }
+  section3.appendChild(chart);
+  panel.appendChild(section3);
+
+  container.appendChild(panel);
+}
+
+module.exports = { renderGoalsPanel };

src/plugins/built-in/writing-studio/panels/manuscript-panel.js

@@ -0,0 +1,124 @@
+function renderManuscriptPanel(container, { engines, editor, settings }) {
+  const projectDir = settings.get('projectDir');
+
+  container.replaceChildren();
+  const panel = document.createElement('div');
+  panel.className = 'ws-panel';
+
+  if (!projectDir) {
+    const empty = document.createElement('div');
+    empty.className = 'ws-empty';
+    const p = document.createElement('p');
+    p.textContent = 'No manuscript project open';
+    empty.appendChild(p);
+    const btn = document.createElement('button');
+    btn.className = 'ws-btn ws-btn-primary';
+    btn.id = 'ws-new-project';
+    btn.textContent = 'New Project';
+    btn.addEventListener('click', () => {
+      const name = prompt('Project name:');
+      if (!name) return;
+      settings.set('projectDir', name);
+      renderManuscriptPanel(container, { engines, editor, settings });
+    });
+    empty.appendChild(btn);
+    panel.appendChild(empty);
+    container.appendChild(panel);
+    return;
+  }
+
+  const project = engines.projects.loadProject(projectDir);
+  if (!project) {
+    const empty = document.createElement('div');
+    empty.className = 'ws-empty';
+    const p = document.createElement('p');
+    p.textContent = 'Project not found at ' + projectDir;
+    empty.appendChild(p);
+    const btn = document.createElement('button');
+    btn.className = 'ws-btn';
+    btn.id = 'ws-clear-project';
+    btn.textContent = 'Clear Project';
+    btn.addEventListener('click', () => {
+      settings.set('projectDir', null);
+      renderManuscriptPanel(container, { engines, editor, settings });
+    });
+    empty.appendChild(btn);
+    panel.appendChild(empty);
+    container.appendChild(panel);
+    return;
+  }
+
+  const stats = engines.projects.getStats(projectDir);
+
+  // Project title + progress
+  const section1 = document.createElement('div');
+  section1.className = 'ws-section';
+  const heading = document.createElement('h3');
+  heading.className = 'ws-heading';
+  heading.textContent = project.title;
+  section1.appendChild(heading);
+
+  const bar = document.createElement('div');
+  bar.className = 'ws-progress-bar';
+  const fill = document.createElement('div');
+  fill.className = 'ws-progress-fill';
+  fill.style.width = stats.pctComplete + '%';
+  bar.appendChild(fill);
+  section1.appendChild(bar);
+
+  const row = document.createElement('div');
+  row.className = 'ws-stat-row';
+  const label = document.createElement('span');
+  label.textContent = stats.totalWords.toLocaleString() + ' / ' + stats.targetWords.toLocaleString() + ' words';
+  const pct = document.createElement('span');
+  pct.className = 'ws-pct';
+  pct.textContent = stats.pctComplete + '%';
+  row.appendChild(label);
+  row.appendChild(pct);
+  section1.appendChild(row);
+  panel.appendChild(section1);
+
+  // Chapters list
+  const section2 = document.createElement('div');
+  section2.className = 'ws-section';
+  const heading2 = document.createElement('h3');
+  heading2.className = 'ws-heading';
+  heading2.textContent = 'Chapters (' + project.chapters.length + ')';
+  section2.appendChild(heading2);
+
+  const chList = document.createElement('div');
+  chList.className = 'ws-chapter-list';
+  for (const ch of project.chapters) {
+    const item = document.createElement('div');
+    item.className = 'ws-chapter-item';
+    const title = document.createElement('span');
+    title.className = 'ws-chapter-title';
+    title.textContent = ch.title || ch.file;
+    const status = document.createElement('span');
+    status.className = 'ws-chapter-status ws-status-' + (ch.status || 'draft');
+    status.textContent = ch.status || 'draft';
+    item.appendChild(title);
+    item.appendChild(status);
+    chList.appendChild(item);
+  }
+  section2.appendChild(chList);
+  panel.appendChild(section2);
+
+  // Compile button
+  const section3 = document.createElement('div');
+  section3.className = 'ws-section';
+  const compileBtn = document.createElement('button');
+  compileBtn.className = 'ws-btn ws-btn-primary';
+  compileBtn.id = 'ws-compile';
+  compileBtn.textContent = 'Compile Manuscript';
+  compileBtn.addEventListener('click', () => {
+    const compiled = engines.projects.compileManuscript(projectDir);
+    editor.insertAtCursor(compiled);
+  });
+  section3.appendChild(compileBtn);
+  panel.appendChild(section3);
+
+  container.appendChild(panel);
+}
+
+module.exports = { renderManuscriptPanel };

src/plugins/built-in/writing-studio/panels/proofread-panel.js

@@ -0,0 +1,97 @@
+function renderProofreadPanel(container, { events, editor }) {
+  const hasAI = events.hasHandler('ai:analyze');
+
+  container.replaceChildren();
+
+  const panel = document.createElement('div');
+  panel.className = 'ws-panel';
+
+  const section = document.createElement('div');
+  section.className = 'ws-section';
+
+  const btn = document.createElement('button');
+  btn.className = 'ws-btn ws-btn-primary';
+  btn.id = 'ws-proofread';
+  btn.textContent = hasAI ? 'Check Document' : 'AI Plugin Required';
+  btn.disabled = !hasAI;
+  section.appendChild(btn);
+
+  if (!hasAI) {
+    const note = document.createElement('p');
+    note.className = 'ws-muted';
+    note.textContent = 'Install the AI Assistant plugin to enable proofreading.';
+    section.appendChild(note);
+  }
+  panel.appendChild(section);
+
+  const issuesList = document.createElement('div');
+  issuesList.className = 'ws-issues-list';
+  issuesList.id = 'ws-issues';
+  panel.appendChild(issuesList);
+
+  container.appendChild(panel);
+
+  if (!hasAI) return;
+
+  container.querySelector('#ws-proofread').addEventListener('click', () => {
+    const content = editor.getContent() || '';
+    events.emit('ai:analyze', {
+      text: content,
+      type: 'grammar',
+      callback: (result) => {
+        if (result && result.issues) {
+          renderIssues(issuesList, result.issues);
+        }
+      }
+    });
+  });
+}
+
+function renderIssues(container, issues) {
+  container.replaceChildren();
+  if (!issues || issues.length === 0) {
+    const p = document.createElement('p');
+    p.className = 'ws-muted';
+    p.textContent = 'No issues found.';
+    container.appendChild(p);
+    return;
+  }
+  for (let i = 0; i < issues.length; i++) {
+    const issue = issues[i];
+    const item = document.createElement('div');
+    item.className = 'ws-issue-item';
+
+    const type = document.createElement('div');
+    type.className = 'ws-issue-type';
+    type.textContent = (issue.type || 'grammar').toUpperCase();
+    item.appendChild(type);
+
+    const text = document.createElement('div');
+    text.className = 'ws-issue-text';
+    text.textContent = issue.message || issue.text || '';
+    item.appendChild(text);
+
+    if (issue.suggestion) {
+      const sug = document.createElement('div');
+      sug.className = 'ws-issue-suggestion';
+      sug.textContent = 'Suggestion: ' + issue.suggestion;
+      item.appendChild(sug);
+    }
+
+    const actions = document.createElement('div');
+    actions.className = 'ws-issue-actions';
+    for (const [action, label] of [['accept', 'Accept'], ['dismiss', 'Dismiss']]) {
+      const actionBtn = document.createElement('button');
+      actionBtn.className = 'ws-btn ws-btn-sm';
+      actionBtn.textContent = label;
+      actionBtn.addEventListener('click', () => {
+        item.remove();
+      });
+      actions.appendChild(actionBtn);
+    }
+    item.appendChild(actions);
+    container.appendChild(item);
+  }
+}
+
+module.exports = { renderProofreadPanel };

src/plugins/built-in/writing-studio/panels/snapshots-panel.js

@@ -0,0 +1,81 @@
+function renderSnapshotsPanel(container, { engines, editor }) {
+  const snapshots = engines.snapshots.list();
+
+  container.replaceChildren();
+
+  const panel = document.createElement('div');
+  panel.className = 'ws-panel';
+
+  // Header with take snapshot button
+  const section = document.createElement('div');
+  section.className = 'ws-section';
+  const btn = document.createElement('button');
+  btn.className = 'ws-btn ws-btn-primary';
+  btn.id = 'ws-take-snapshot';
+  btn.textContent = 'Take Snapshot';
+  section.appendChild(btn);
+  const count = document.createElement('span');
+  count.className = 'ws-muted';
+  count.textContent = snapshots.length + ' snapshots';
+  section.appendChild(count);
+  panel.appendChild(section);
+
+  // Snapshot list
+  const list = document.createElement('div');
+  list.className = 'ws-snapshot-list';
+  for (const s of snapshots) {
+    const item = document.createElement('div');
+    item.className = 'ws-snapshot-item';
+
+    const header = document.createElement('div');
+    header.className = 'ws-snapshot-header';
+    const sLabel = document.createElement('span');
+    sLabel.className = 'ws-snapshot-label';
+    sLabel.textContent = s.label;
+    const sWords = document.createElement('span');
+    sWords.textContent = s.wordCount + ' words';
+    header.appendChild(sLabel);
+    header.appendChild(sWords);
+    item.appendChild(header);
+
+    const time = document.createElement('div');
+    time.className = 'ws-snapshot-time';
+    time.textContent = new Date(s.timestamp).toLocaleString();
+    item.appendChild(time);
+
+    const actions = document.createElement('div');
+    actions.className = 'ws-snapshot-actions';
+    for (const [action, text, cls] of [['restore', 'Restore', ''], ['diff', 'Diff', ''], ['delete', 'Delete', 'ws-btn-danger']]) {
+      const actionBtn = document.createElement('button');
+      actionBtn.className = 'ws-btn ws-btn-sm' + (cls ? ' ' + cls : '');
+      actionBtn.textContent = text;
+      actionBtn.addEventListener('click', () => {
+        if (action === 'restore') {
+          const content = engines.snapshots.restore(s.id);
+          editor.insertAtCursor(content);
+        } else if (action === 'delete') {
+          engines.snapshots.delete(s.id);
+          renderSnapshotsPanel(container, { engines, editor });
+        } else if (action === 'diff') {
+          const current = editor.getContent() || '';
+          const result = engines.snapshots.diff(s.id, current);
+          alert('+' + result.added + ' lines added, -' + result.removed + ' lines removed');
+        }
+      });
+      actions.appendChild(actionBtn);
+    }
+    item.appendChild(actions);
+    list.appendChild(item);
+  }
+  panel.appendChild(list);
+  container.appendChild(panel);
+
+  // Take snapshot button handler
+  container.querySelector('#ws-take-snapshot').addEventListener('click', () => {
+    const content = editor.getContent() || '';
+    engines.snapshots.create(content, 'manual');
+    renderSnapshotsPanel(container, { engines, editor });
+  });
+}
+
+module.exports = { renderSnapshotsPanel };

src/plugins/built-in/writing-studio/project-manager.js

@@ -0,0 +1,74 @@
+class ProjectManager {
+  /**
+   * @param {object} fs - { readFile(path), writeFile(path, content), fileExists(path), listDir(path) }
+   */
+  constructor(fs) {
+    this.fs = fs;
+  }
+
+  createProject(dir, opts) {
+    const project = {
+      title: opts.title,
+      type: opts.type || 'manuscript',
+      target: { words: opts.targetWords || 0, deadline: opts.deadline || null },
+      chapters: [],
+      metadata: opts.metadata || {}
+    };
+    this.fs.writeFile(dir + '/.project.json', JSON.stringify(project, null, 2));
+    return project;
+  }
+
+  loadProject(dir) {
+    const raw = this.fs.readFile(dir + '/.project.json');
+    if (!raw) return null;
+    return JSON.parse(raw);
+  }
+
+  _saveProject(dir, project) {
+    this.fs.writeFile(dir + '/.project.json', JSON.stringify(project, null, 2));
+  }
+
+  addChapter(dir, chapter) {
+    const project = this.loadProject(dir);
+    if (!project) throw new Error('Project not found');
+    project.chapters.push(chapter);
+    this._saveProject(dir, project);
+  }
+
+  updateChapter(dir, index, updates) {
+    const project = this.loadProject(dir);
+    if (!project) throw new Error('Project not found');
+    Object.assign(project.chapters[index], updates);
+    this._saveProject(dir, project);
+  }
+
+  compileManuscript(dir) {
+    const project = this.loadProject(dir);
+    if (!project) throw new Error('Project not found');
+    const parts = [];
+    for (const ch of project.chapters) {
+      const content = this.fs.readFile(dir + '/' + ch.file);
+      if (content) parts.push(content);
+    }
+    return parts.join('\n\n---\n\n');
+  }
+
+  getStats(dir) {
+    const project = this.loadProject(dir);
+    if (!project) throw new Error('Project not found');
+    let totalWords = 0;
+    for (const ch of project.chapters) {
+      const content = this.fs.readFile(dir + '/' + ch.file);
+      if (content) totalWords += content.split(/\s+/).filter(Boolean).length;
+    }
+    const target = project.target.words || 0;
+    return {
+      totalWords,
+      chapterCount: project.chapters.length,
+      targetWords: target,
+      pctComplete: target > 0 ? Math.min(100, Math.round((totalWords / target) * 100)) : 0
+    };
+  }
+}
+
+module.exports = { ProjectManager };

src/plugins/built-in/writing-studio/snapshot-manager.js

@@ -0,0 +1,73 @@
+class SnapshotManager {
+  /**
+   * @param {object} store - { get(key), set(key, value) }
+   * @param {string} storeKey - settings key for snapshots
+   */
+  constructor(store, storeKey = 'plugins.writing-studio.snapshots') {
+    this.store = store;
+    this.storeKey = storeKey;
+  }
+
+  _getAll() {
+    const raw = this.store.get(this.storeKey);
+    return raw ? JSON.parse(raw) : [];
+  }
+
+  _saveAll(snaps) {
+    this.store.set(this.storeKey, JSON.stringify(snaps));
+  }
+
+  create(content, label = 'manual') {
+    const snaps = this._getAll();
+    const snap = {
+      id: 'snap-' + Date.now() + '-' + Math.random().toString(36).slice(2, 8),
+      timestamp: new Date().toISOString(),
+      content,
+      wordCount: content.split(/\s+/).filter(Boolean).length,
+      label
+    };
+    snaps.unshift(snap);
+    this._saveAll(snaps);
+    return snap;
+  }
+
+  list() {
+    return this._getAll();
+  }
+
+  getById(id) {
+    return this._getAll().find(s => s.id === id) || null;
+  }
+
+  restore(id) {
+    const snap = this.getById(id);
+    if (!snap) throw new Error('Snapshot not found');
+    return snap.content;
+  }
+
+  delete(id) {
+    const snaps = this._getAll().filter(s => s.id !== id);
+    this._saveAll(snaps);
+  }
+
+  diff(id, currentContent) {
+    const snap = this.getById(id);
+    if (!snap) throw new Error('Snapshot not found');
+    const oldLines = snap.content.split('\n');
+    const newLines = currentContent.split('\n');
+    const oldSet = new Set(oldLines);
+    const newSet = new Set(newLines);
+    let added = 0;
+    let removed = 0;
+    for (const line of newLines) { if (!oldSet.has(line)) added++; }
+    for (const line of oldLines) { if (!newSet.has(line)) removed++; }
+    return { added, removed };
+  }
+
+  prune(keepCount) {
+    const snaps = this._getAll();
+    this._saveAll(snaps.slice(0, keepCount));
+  }
+}
+
+module.exports = { SnapshotManager };

src/plugins/built-in/writing-studio/sprint-engine.js

@@ -0,0 +1,51 @@
+class SprintEngine {
+  /**
+   * @param {object} opts
+   * @param {function} opts.onEvent - callback(event_name, data)
+   */
+  constructor(opts = {}) {
+    this.onEvent = opts.onEvent || (() => {});
+    this._active = false;
+    this._startTime = null;
+    this._duration = 0;
+    this._initialWords = 0;
+  }
+
+  start(durationMinutes, currentWordCount) {
+    if (this._active) throw new Error('Sprint already active');
+    this._active = true;
+    this._startTime = Date.now();
+    this._duration = durationMinutes * 60 * 1000;
+    this._initialWords = currentWordCount;
+  }
+
+  stop(currentWordCount) {
+    if (!this._active) throw new Error('No active sprint');
+    const elapsed = Date.now() - this._startTime;
+    const wordDelta = Math.max(0, currentWordCount - this._initialWords);
+    const elapsedMinutes = elapsed / 60000;
+    const wpm = elapsedMinutes > 0 ? Math.round(wordDelta / elapsedMinutes) : 0;
+    this._active = false;
+    this._startTime = null;
+    return { wordDelta, elapsed, wpm };
+  }
+
+  tick(elapsedMs) {
+    if (!this._active) return;
+    const remaining = Math.max(0, this._duration - elapsedMs);
+    this.onEvent('sprint:tick', { remaining, elapsed: elapsedMs });
+    if (remaining <= 0) {
+      this._active = false;
+      this.onEvent('sprint:complete', { expired: true });
+    }
+  }
+
+  isActive() { return this._active; }
+
+  getRemaining() {
+    if (!this._active) return 0;
+    return Math.max(0, this._duration - (Date.now() - this._startTime));
+  }
+}
+
+module.exports = { SprintEngine };

src/plugins/event-bus.js

@@ -0,0 +1,43 @@
+class EventBus {
+  constructor() {
+    this.listeners = new Map();
+  }
+
+  on(event, handler) {
+    if (!this.listeners.has(event)) {
+      this.listeners.set(event, []);
+    }
+    this.listeners.get(event).push(handler);
+  }
+
+  off(event, handler) {
+    if (!handler) {
+      this.listeners.delete(event);
+      return;
+    }
+    const handlers = this.listeners.get(event);
+    if (handlers) {
+      const idx = handlers.indexOf(handler);
+      if (idx !== -1) handlers.splice(idx, 1);
+    }
+  }
+
+  emit(event, payload) {
+    const handlers = this.listeners.get(event);
+    if (!handlers) return;
+    for (const handler of handlers) {
+      try {
+        handler(payload);
+      } catch (err) {
+        console.error(`[EventBus] Error in handler for "${event}":`, err);
+      }
+    }
+  }
+
+  hasHandler(event) {
+    const handlers = this.listeners.get(event);
+    return handlers !== undefined && handlers !== null && handlers.length > 0;
+  }
+}
+
+module.exports = { EventBus };

src/plugins/plugin-api.js

@@ -0,0 +1,23 @@
+class PluginAPI {
+  /**
+   * Called when the plugin is discovered and loaded.
+   * Receives a scoped context object with APIs.
+   * @param {object} context - Plugin context (sidebar, commands, settings, etc.)
+   */
+  init(context) {
+    this.context = context;
+  }
+
+  /** Called when the plugin is activated (e.g., sidebar panel clicked). */
+  activate() {}
+
+  /** Called when the plugin is deactivated. */
+  deactivate() {}
+
+  /** Returns the parsed manifest.json for this plugin. */
+  getManifest() {
+    return this._manifest || null;
+  }
+}
+
+module.exports = { PluginAPI };

src/plugins/plugin-context.js

@@ -0,0 +1,70 @@
+class PluginContext {
+  /**
+   * @param {object} deps - Injected dependencies
+   * @param {string} deps.pluginId - Plugin unique ID (for namespacing)
+   * @param {object} deps.sidebar - SidebarManager.registerPanel
+   * @param {object} deps.commands - CommandPalette.register
+   * @param {object} deps.statusBar - StatusBar.registerIndicator
+   * @param {object} deps.eventBus - EventBus instance
+   * @param {object} deps.settings - { get, set, onChanged }
+   * @param {object} deps.editor - { getContent, getSelection, insertAtCursor, onContentChanged }
+   * @param {object} deps.ipc - { invoke, on }
+   * @param {object} deps.exportHooks - { preHooks: [], postHooks: [] }
+   */
+  constructor(deps) {
+    const { pluginId, sidebar, commands, statusBar, eventBus, settings, editor, ipc, exportHooks } = deps;
+
+    this.sidebar = {
+      registerPanel: (id, opts) => sidebar.registerPanel(`${pluginId}:${id}`, opts)
+    };
+
+    this.commands = {
+      register: (id, label, handler, shortcut) => {
+        const safeHandler = (...args) => {
+          try {
+            handler(...args);
+          } catch (err) {
+            console.error(`[Plugin:${pluginId}] Command "${id}" error:`, err);
+          }
+        };
+        commands.register(`${pluginId}:${id}`, label, safeHandler, shortcut);
+      }
+    };
+
+    this.statusBar = {
+      registerIndicator: (id, opts) => statusBar.registerIndicator(`${pluginId}:${id}`, opts)
+    };
+
+    this.settings = {
+      get: (key) => settings.get(`plugins.${pluginId}.${key}`),
+      set: (key, value) => settings.set(`plugins.${pluginId}.${key}`, value),
+      onChanged: (key, cb) => settings.onChanged(`plugins.${pluginId}.${key}`, cb)
+    };
+
+    this.editor = {
+      getContent: () => editor.getContent(),
+      getSelection: () => editor.getSelection(),
+      insertAtCursor: (text) => editor.insertAtCursor(text),
+      onContentChanged: (cb) => editor.onContentChanged(cb)
+    };
+
+    this.events = {
+      on: (event, handler) => eventBus.on(event, handler),
+      off: (event, handler) => eventBus.off(event, handler),
+      emit: (event, payload) => eventBus.emit(event, payload),
+      hasHandler: (event) => eventBus.hasHandler(event)
+    };
+
+    this.ipc = {
+      invoke: (channel, ...args) => ipc.invoke(channel, ...args),
+      on: (channel, handler) => ipc.on(channel, handler)
+    };
+
+    this.exports = {
+      registerPreHook: (handler) => { if (exportHooks) exportHooks.preHooks.push(handler); },
+      registerPostHook: (handler) => { if (exportHooks) exportHooks.postHooks.push(handler); }
+    };
+  }
+}
+
+module.exports = { PluginContext };

src/plugins/plugin-loader.js

@@ -0,0 +1,75 @@
+const fs = require('fs');
+const path = require('path');
+
+class PluginLoader {
+  /**
+   * @param {string[]} searchDirs - Directories to scan for plugin folders
+   */
+  constructor(searchDirs = []) {
+    this.searchDirs = searchDirs;
+    this.loadedIds = new Set();
+  }
+
+  /**
+   * Discover plugins by scanning searchDirs for manifest.json files.
+   * Returns array of { id, name, version, description, manifest, PluginClass, dir }
+   */
+  discoverPlugins() {
+    const plugins = [];
+    for (const dir of this.searchDirs) {
+      if (!fs.existsSync(dir)) continue;
+      const entries = fs.readdirSync(dir, { withFileTypes: true });
+      for (const entry of entries) {
+        if (!entry.isDirectory()) continue;
+        const pluginDir = path.join(dir, entry.name);
+        const manifestPath = path.join(pluginDir, 'manifest.json');
+        if (!fs.existsSync(manifestPath)) continue;
+        try {
+          const raw = fs.readFileSync(manifestPath, 'utf-8');
+          const manifest = JSON.parse(raw);
+          this.validateManifest(manifest);
+          let PluginClass = null;
+          const indexPath = path.join(pluginDir, 'index.js');
+          if (fs.existsSync(indexPath)) {
+            try {
+              const loaded = require(indexPath);
+              PluginClass = loaded.Plugin || loaded.default || null;
+            } catch (err) {
+              console.error(`[PluginLoader] Failed to load index.js for "${manifest.id}":`, err.message);
+              continue;
+            }
+          }
+          plugins.push({
+            id: manifest.id,
+            name: manifest.name,
+            version: manifest.version,
+            description: manifest.description,
+            manifest,
+            PluginClass,
+            dir: pluginDir
+          });
+          this.loadedIds.add(manifest.id);
+        } catch (err) {
+          console.error(`[PluginLoader] Skipping plugin in ${pluginDir}:`, err.message);
+        }
+      }
+    }
+    return plugins;
+  }
+
+  /**
+   * Validate a manifest object. Throws on invalid.
+   */
+  validateManifest(manifest) {
+    if (!manifest.id) throw new Error('Manifest missing required field: id');
+    if (!manifest.name) throw new Error('Manifest missing required field: name');
+    if (!manifest.version) throw new Error('Manifest missing required field: version');
+    if (!manifest.description) throw new Error('Manifest missing required field: description');
+    if (this.loadedIds.has(manifest.id)) {
+      throw new Error(`Duplicate plugin id: "${manifest.id}"`);
+    }
+    return true;
+  }
+}
+
+module.exports = { PluginLoader };

src/plugins/plugin-registry.js

@@ -0,0 +1,80 @@
+const { PluginContext } = require('./plugin-context');
+const { PluginAPI } = require('./plugin-api');
+
+class PluginRegistry {
+  constructor(deps) {
+    this.deps = deps;
+    this.plugins = new Map();
+    this.exportHooks = { preHooks: [], postHooks: [] };
+  }
+
+  /**
+   * Register a discovered plugin. Creates instance, builds context, calls init.
+   * If init throws, plugin is NOT registered.
+   */
+  register(pluginInfo) {
+    const { id, name, version, description, manifest, PluginClass, dir } = pluginInfo;
+
+    let instance;
+    if (PluginClass) {
+      instance = new PluginClass();
+    } else {
+      instance = new PluginAPI();
+    }
+    instance._manifest = manifest;
+
+    const context = new PluginContext({
+      pluginId: id,
+      sidebar: this.deps.sidebar,
+      commands: this.deps.commands,
+      statusBar: this.deps.statusBar,
+      eventBus: this.deps.eventBus,
+      settings: this.deps.settings,
+      editor: this.deps.editor,
+      ipc: this.deps.ipc,
+      exportHooks: this.exportHooks
+    });
+
+    try {
+      instance.init(context);
+    } catch (err) {
+      console.error(`[PluginRegistry] Plugin "${id}" init failed:`, err.message);
+      return;
+    }
+
+    this.plugins.set(id, { id, name, version, description, manifest, instance, dir, context });
+    console.log(`[PluginRegistry] Registered plugin: ${name} v${version}`);
+  }
+
+  getPlugin(id) {
+    return this.plugins.get(id);
+  }
+
+  getAll() {
+    return Array.from(this.plugins.values());
+  }
+
+  activate(id) {
+    const plugin = this.plugins.get(id);
+    if (plugin?.instance) {
+      try {
+        plugin.instance.activate();
+      } catch (err) {
+        console.error(`[PluginRegistry] Plugin "${id}" activate error:`, err.message);
+      }
+    }
+  }
+
+  deactivate(id) {
+    const plugin = this.plugins.get(id);
+    if (plugin?.instance) {
+      try {
+        plugin.instance.deactivate();
+      } catch (err) {
+        console.error(`[PluginRegistry] Plugin "${id}" deactivate error:`, err.message);
+      }
+    }
+  }
+}
+
+module.exports = { PluginRegistry };

src/plugins/settings-store.js

@@ -0,0 +1,23 @@
+class SettingsStore {
+  /**
+   * @param {object} backend - { get(key), set(key, value) } backed by main process store
+   */
+  constructor(backend) {
+    this.backend = backend;
+  }
+
+  get(key) {
+    return this.backend.get(key);
+  }
+
+  set(key, value) {
+    this.backend.set(key, value);
+  }
+
+  onChanged(key, callback) {
+    // Deferred: plugins read settings on init/activate for MVP.
+    // Full change notification requires IPC watcher in main process.
+  }
+}
+
+module.exports = { SettingsStore };

src/preload.js

@@ -9,7 +9,7 @@
  * - All IPC channels are explicitly whitelisted
  * - Prevents XSS from escalating to full system access
  *
- * @version 4.0.0
+ * @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',
@@ -101,6 +102,14 @@ const ALLOWED_SEND_CHANNELS = [
 
   // File Explorer
   'list-directory',
+  'read-file',
+  'write-file',
+  'delete-file',
+  'ensure-directory',
+  'path-exists',
+  'is-directory',
+  'copy-path',
+  'move-path',
 
   // Git
   'git-status',
@@ -127,7 +136,11 @@ const ALLOWED_SEND_CHANNELS = [
   'export',
 
   // Git diff
-  'git-diff'
+  'git-diff',
+
+  // Plugin settings
+  'plugin-settings:get',
+  'plugin-settings:set'
 ];
 
 const ALLOWED_RECEIVE_CHANNELS = [
@@ -138,6 +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',
@@ -222,7 +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'
 ];
 
 /**
@@ -321,7 +341,18 @@ contextBridge.exposeInMainWorld('electronAPI', {
     setCurrent: (filePath) => ipcRenderer.send('set-current-file', filePath),
     saveRecent: (recentFiles) => ipcRenderer.send('save-recent-files', recentFiles),
     clearRecent: () => ipcRenderer.send('clear-recent-files'),
-    rendererReady: () => ipcRenderer.send('renderer-ready')
+    rendererReady: () => ipcRenderer.send('renderer-ready'),
+    read: (filePath) => ipcRenderer.invoke('read-file', filePath),
+    write: (filePath, content) => ipcRenderer.invoke('write-file', { path: filePath, content }),
+    delete: (filePath) => ipcRenderer.invoke('delete-file', filePath),
+    ensureDir: (dirPath) => ipcRenderer.invoke('ensure-directory', dirPath),
+    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 }),
+    list: (dirPath) => ipcRenderer.invoke('list-directory', dirPath),
+    pickFolder: () => ipcRenderer.invoke('pick-folder'),
+    pickFile: () => ipcRenderer.invoke('pick-file')
   },
 
   // Theme Operations
@@ -413,7 +444,9 @@ contextBridge.exposeInMainWorld('electronAPI', {
   generators: {
     openAscii: () => ipcRenderer.send('open-ascii-generator'),
     openTable: () => ipcRenderer.send('open-table-generator')
-  }
+  },
+
+  getAppVersion: () => ipcRenderer.invoke('get-app-version')
 });
 
 // Log successful preload initialization

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 +1,54 @@
+import { PanelLeft, PanelRight, Keyboard } from 'lucide-react';
+import { Button } from '@/components/ui/button';
+import { ThemeToggle } from '@/components/theme-toggle';
+import { useAppStore } from '@/stores/app-store';
+import { useCommandStore } from '@/stores/command-store';
+
+export function AppHeader() {
+  const { sidebarVisible, previewVisible } = useAppStore();
+  const dispatch = useCommandStore((s) => s.dispatch);
+
+  return (
+    <header className="flex h-14 items-center justify-between border-b border-border bg-card/40 px-4 backdrop-blur">
+      <div className="flex items-center gap-3">
+        <div
+          className="h-7 w-7 rounded-md bg-gradient-to-br from-brand to-brand-dark shadow-[var(--shadow-glow-brand)]"
+          aria-label="MarkdownConverter logo"
+        />
+        <h1 className="font-display text-lg font-bold tracking-tight">MarkdownConverter</h1>
+      </div>
+      <div className="flex items-center gap-1">
+        <Button
+          variant="ghost"
+          size="icon"
+          aria-label="Toggle sidebar"
+          aria-pressed={sidebarVisible}
+          data-testid="header-toggle-sidebar"
+          onClick={() => dispatch('view.toggleSidebar')}
+        >
+          <PanelLeft className="h-4 w-4" />
+        </Button>
+        <Button
+          variant="ghost"
+          size="icon"
+          aria-label="Toggle preview"
+          aria-pressed={previewVisible}
+          data-testid="header-toggle-preview"
+          onClick={() => dispatch('view.togglePreview')}
+        >
+          <PanelRight className="h-4 w-4" />
+        </Button>
+        <Button
+          variant="ghost"
+          size="icon"
+          aria-label="Keyboard shortcuts"
+          data-testid="header-shortcuts"
+          onClick={() => dispatch('shortcuts.show')}
+        >
+          <Keyboard className="h-4 w-4" />
+        </Button>
+        <ThemeToggle />
+      </div>
+    </header>
+  );
+}

src/renderer/components/layout/AppShell.tsx

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

src/renderer/components/layout/Breadcrumb.tsx

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

src/renderer/components/layout/StatusBar.tsx

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

src/renderer/components/layout/TabBar.tsx

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

src/renderer/components/layout/Toolbar.tsx

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

src/renderer/components/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-menu-action.ts

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

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

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

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

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

src/renderer/hooks/use-shortcut.ts

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

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

@@ -0,0 +1,74 @@
+import { useEffect } from 'react';
+import { useCommandStore } from '@/stores/command-store';
+import { useFileStore } from '@/stores/file-store';
+import { useAppStore } from '@/stores/app-store';
+import { useMenuAction } from '@/hooks/use-menu-action';
+
+/**
+ * Register all Phase 6 menu commands in the command store, and bridge
+ * the native menu IPC channels to the matching command ids.
+ *
+ * Phase 6 scope: file/view/tab commands with direct store mappings.
+ * Phase 7+ will add the dialog-driven commands (export, settings, etc.)
+ * once the corresponding modals exist.
+ */
+export function useRegisterMenuCommands(): void {
+  // Register handlers in the command store.
+  useEffect(() => {
+    const { register } = useCommandStore.getState();
+    register('file.open', () => {
+      void useFileStore.getState().openFileDialog();
+    });
+    register('file.openFolder', () => {
+      void useFileStore.getState().openFolderDialog();
+    });
+    register('file.save', () => {
+      void useFileStore.getState().saveActiveBuffer();
+    });
+    register('file.closeTab', () => {
+      const { activeTabId, closeTab } = useFileStore.getState();
+      if (activeTabId) closeTab(activeTabId);
+    });
+    register('tab.next', () => {
+      const { openTabs, activeTabId, setActiveTab } = useFileStore.getState();
+      if (openTabs.length === 0) return;
+      const idx = activeTabId ? openTabs.findIndex((t) => t.id === activeTabId) : 0;
+      const safeIdx = idx === -1 ? 0 : idx;
+      const nextIdx = safeIdx >= openTabs.length - 1 ? 0 : safeIdx + 1;
+      setActiveTab(openTabs[nextIdx].id);
+    });
+    register('tab.prev', () => {
+      const { openTabs, activeTabId, setActiveTab } = useFileStore.getState();
+      if (openTabs.length === 0) return;
+      const idx = activeTabId ? openTabs.findIndex((t) => t.id === activeTabId) : 0;
+      const safeIdx = idx === -1 ? 0 : idx;
+      const nextIdx = safeIdx <= 0 ? openTabs.length - 1 : safeIdx - 1;
+      setActiveTab(openTabs[nextIdx].id);
+    });
+    register('view.toggleSidebar', () => useAppStore.getState().toggleSidebar());
+    register('view.togglePreview', () => useAppStore.getState().togglePreview());
+  }, []);
+}
+
+/**
+ * Wire native-menu IPC channels to the command store.
+ * Channel names match what main.js dispatches via webContents.send.
+ */
+export function useBridgeNativeMenu(): void {
+  useMenuAction('file-save', 'file.save');
+  useMenuAction('toggle-preview', 'view.togglePreview');
+  useMenuAction('toggle-command-palette', 'command.palette');
+  useMenuAction('toggle-sidebar-panel', 'view.sidebarPanel', (panel) => panel as string);
+  useMenuAction('toggle-bottom-panel', 'view.bottomPanel');
+  useMenuAction('toggle-find', 'find.toggle');
+  useMenuAction('undo', 'editor.undo');
+  useMenuAction('redo', 'editor.redo');
+  useMenuAction('adjust-font-size', 'font.size', (direction) => direction as string);
+  useMenuAction('load-custom-css', 'theme.loadCustomCss');
+  useMenuAction('clear-custom-css', 'theme.clearCustomCss');
+  useMenuAction('load-template-menu', 'template.load', (name) => name as string);
+  useMenuAction('print-preview', 'print.preview');
+  useMenuAction('print-preview-styled', 'print.previewStyled');
+  useMenuAction('file-opened', 'file.opened', (payload) => payload);
+  useMenuAction('clear-recent-files', 'file.clearRecent');
+}

src/renderer/lib/ipc.ts

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

src/renderer/lib/markdown.ts

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

src/renderer/lib/motion.ts

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

src/renderer/lib/utils.ts

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

src/renderer/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/command-store.ts

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

src/renderer/stores/editor-store.ts

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

src/renderer/stores/file-store.ts

@@ -0,0 +1,235 @@
+import { create } from 'zustand';
+import { persist, createJSONStorage } from 'zustand/middleware';
+import { immer } from 'zustand/middleware/immer';
+import { enableMapSet } from 'immer';
+import { ipc } from '@/lib/ipc';
+import { useEditorStore } from '@/stores/editor-store';
+import type { FileEntry } from '@/types/ipc';
+
+enableMapSet();
+
+export interface FileNode {
+  name: string;
+  path: string;
+  isDirectory: boolean;
+  children: FileNode[] | null;
+  expanded?: boolean;
+  loaded?: boolean;
+}
+
+export interface OpenTab {
+  id: string;
+  path: string;
+  title: string;
+  dirty: boolean;
+}
+
+interface FileState {
+  tree: FileNode | null;
+  rootPath: string | null;
+  expanded: Set<string>;
+  openTabs: OpenTab[];
+  activeTabId: string | null;
+
+  openFolder: (path: string) => Promise<void>;
+  loadChildren: (dirPath: string) => Promise<void>;
+  toggleExpanded: (dirPath: string) => void;
+  openFile: (filePath: string) => Promise<void>;
+  closeTab: (id: string) => void;
+  setActiveTab: (id: string) => void;
+  markTabClean: (id: string) => void;
+  markTabDirty: (id: string) => void;
+  reorderTabs: (fromIndex: number, toIndex: number) => void;
+  openFolderDialog: () => Promise<void>;
+  openFileDialog: () => Promise<void>;
+  saveActiveBuffer: () => Promise<boolean>;
+}
+
+function entryToNode(entry: FileEntry): FileNode {
+  return {
+    name: entry.name,
+    path: entry.path,
+    isDirectory: entry.isDirectory,
+    children: null, // lazy: start unloaded; loadChildren populates this
+  };
+}
+
+// Recursively find and update a directory node by path using immer's produce
+function updateNode(tree: FileNode, dirPath: string, updater: (node: FileNode) => void): boolean {
+  if (tree.path === dirPath && tree.isDirectory) {
+    updater(tree);
+    return true;
+  }
+  if (tree.children) {
+    for (const child of tree.children) {
+      if (updateNode(child, dirPath, updater)) return true;
+    }
+  }
+  return false;
+}
+
+export const useFileStore = create<FileState>()(
+  persist(
+    immer((set) => ({
+    tree: null,
+    rootPath: null,
+    expanded: new Set<string>(),
+    openTabs: [],
+    activeTabId: null,
+
+    openFolder: async (path) => {
+      const result = await ipc.file.list(path);
+      if (!result.ok) return;
+
+      const children: FileNode[] = result.data!.map(entryToNode);
+
+      set((s) => {
+        s.tree = {
+          name: path.split('/').filter(Boolean).pop() ?? path,
+          path,
+          isDirectory: true,
+          children,
+          loaded: true,
+        };
+        s.rootPath = path;
+      });
+    },
+
+    loadChildren: async (dirPath) => {
+      // Find the node first
+      const tree = useFileStore.getState().tree;
+      if (!tree) return;
+
+      let found = false;
+      updateNode(tree, dirPath, (node) => {
+        if (node.loaded === true) return;
+        found = true;
+      });
+      if (!found) return;
+
+      const result = await ipc.file.list(dirPath);
+      if (!result.ok) return;
+
+      set((s) => {
+        updateNode(s.tree!, dirPath, (node) => {
+          node.children = result.data!.map(entryToNode);
+          node.loaded = true;
+        });
+      });
+    },
+
+    toggleExpanded: (dirPath) => {
+      set((s) => {
+        if (s.expanded.has(dirPath)) {
+          s.expanded.delete(dirPath);
+        } else {
+          s.expanded.add(dirPath);
+        }
+      });
+    },
+
+    openFile: async (filePath) => {
+      // If already open, sync dirty flag from editor buffer and activate
+      const existing = useFileStore.getState().openTabs.find((t) => t.id === filePath);
+      if (existing) {
+        const buffer = useEditorStore.getState().buffers.get(filePath);
+        set((s) => {
+          s.activeTabId = filePath;
+          if (buffer) {
+            const tab = s.openTabs.find((t) => t.id === filePath);
+            if (tab) tab.dirty = buffer.dirty;
+          }
+        });
+        return;
+      }
+
+      const result = await ipc.file.read(filePath);
+      if (!result.ok) return;
+
+      const content = result.data!;
+      const title = filePath.split('/').pop() ?? filePath;
+
+      // Open in editor store
+      useEditorStore.getState().openBuffer(filePath, filePath, content);
+
+      set((s) => {
+        s.openTabs.push({ id: filePath, path: filePath, title, dirty: false });
+        s.activeTabId = filePath;
+      });
+    },
+
+    closeTab: (id) => {
+      set((s) => {
+        const idx = s.openTabs.findIndex((t) => t.id === id);
+        if (idx === -1) return;
+        s.openTabs.splice(idx, 1);
+        if (s.activeTabId === id) {
+          s.activeTabId = idx > 0 ? s.openTabs[idx - 1]?.id ?? null : null;
+        }
+      });
+    },
+
+    setActiveTab: (id) => {
+      set((s) => {
+        s.activeTabId = id;
+      });
+    },
+
+    markTabClean: (id) => {
+      set((s) => {
+        const tab = s.openTabs.find((t) => t.id === id);
+        if (tab) tab.dirty = false;
+      });
+    },
+
+    markTabDirty: (id) => {
+      set((s) => {
+        const tab = s.openTabs.find((t) => t.id === id);
+        if (tab) tab.dirty = true;
+      });
+    },
+
+    reorderTabs: (fromIndex, toIndex) => {
+      set((s) => {
+        const tabs = s.openTabs;
+        const [moved] = tabs.splice(fromIndex, 1);
+        tabs.splice(toIndex, 0, moved);
+      });
+    },
+
+    openFolderDialog: async () => {
+      const result = await ipc.file.pickFolder();
+      if (!result.ok || result.data === null) return;
+      await useFileStore.getState().openFolder(result.data);
+    },
+
+    openFileDialog: async () => {
+      const result = await ipc.file.pickFile();
+      if (!result.ok || result.data === null) return;
+      await useFileStore.getState().openFile(result.data);
+    },
+
+    saveActiveBuffer: async () => {
+      const { activeTabId } = useFileStore.getState();
+      if (!activeTabId) return false;
+
+      const buffer = useEditorStore.getState().buffers.get(activeTabId);
+      if (!buffer) return false;
+
+      const writeResult = await ipc.file.write(activeTabId, buffer.content);
+      if (!writeResult.ok) return false;
+
+      useEditorStore.getState().markSaved(activeTabId);
+      useFileStore.getState().markTabClean(activeTabId);
+      return true;
+    },
+  })),
+    {
+      name: 'mc-file-store',
+      storage: createJSONStorage(() => localStorage),
+      // Only persist the folder path; tree, expanded Set, and openTabs are
+      // rebuilt on demand. The app re-opens the folder on startup.
+      partialize: (state) => ({ rootPath: state.rootPath }),
+    }
+  )
+);

src/renderer/stores/preview-store.ts

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

src/renderer/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/sidebar/outline-panel.js

@@ -0,0 +1,114 @@
+/**
+ * Document Outline Panel
+ * Parses markdown headings and renders a navigable tree in the sidebar.
+ */
+
+function renderOutlinePanel(container, { getEditorContent, getActiveLine, onHeadingClick }) {
+    container.innerHTML = `
+        <div class="outline-panel">
+            <div class="outline-list" id="outline-list"></div>
+        </div>
+    `;
+
+    const listEl = document.getElementById('outline-list');
+    let headings = [];
+    let activeLine = 1;
+    let debounceTimer = null;
+
+    function parseHeadings(content) {
+        const result = [];
+        if (!content) return result;
+        const lines = content.split('\n');
+        const regex = /^(#{1,6})\s+(.+)$/;
+        for (let i = 0; i < lines.length; i++) {
+            const match = regex.exec(lines[i]);
+            if (match) {
+                result.push({
+                    level: match[1].length,
+                    text: match[2].trim(),
+                    line: i + 1
+                });
+            }
+        }
+        return result;
+    }
+
+    function findActiveHeading(currentLine) {
+        let active = null;
+        for (const h of headings) {
+            if (h.line <= currentLine) {
+                active = h;
+            } else {
+                break;
+            }
+        }
+        return active;
+    }
+
+    function renderHeadings() {
+        const content = getEditorContent();
+        headings = parseHeadings(content);
+        activeLine = getActiveLine();
+
+        if (headings.length === 0) {
+            listEl.innerHTML = `
+                <div class="outline-empty">
+                    <p>No headings found</p>
+                    <p class="outline-hint"># Heading 1</p>
+                    <p class="outline-hint">## Heading 2</p>
+                    <p class="outline-hint">### Heading 3</p>
+                </div>
+            `;
+            return;
+        }
+
+        const activeHeading = findActiveHeading(activeLine);
+
+        listEl.innerHTML = headings.map((h, idx) => `
+            <div class="outline-item outline-level-${h.level}${activeHeading && h.line === activeHeading.line ? ' active' : ''}"
+                 data-line="${h.line}" data-index="${idx}">
+                <span class="outline-text">${escapeHtml(h.text)}</span>
+                <span class="outline-badge">H${h.level}</span>
+            </div>
+        `).join('') + `<div class="outline-footer">${headings.length} heading${headings.length !== 1 ? 's' : ''}</div>`;
+
+        listEl.querySelectorAll('.outline-item').forEach(item => {
+            item.addEventListener('click', () => {
+                const line = parseInt(item.dataset.line, 10);
+                onHeadingClick(line);
+            });
+        });
+    }
+
+    function escapeHtml(text) {
+        const div = document.createElement('div');
+        div.textContent = text;
+        return div.innerHTML;
+    }
+
+    function refresh() {
+        clearTimeout(debounceTimer);
+        debounceTimer = setTimeout(renderHeadings, 300);
+    }
+
+    function setActiveHeading(line) {
+        activeLine = line;
+        const activeHeading = findActiveHeading(line);
+
+        listEl.querySelectorAll('.outline-item').forEach(item => {
+            const itemLine = parseInt(item.dataset.line, 10);
+            if (activeHeading && itemLine === activeHeading.line) {
+                item.classList.add('active');
+            } else {
+                item.classList.remove('active');
+            }
+        });
+    }
+
+    container._refreshOutline = refresh;
+    container._setActiveHeading = setActiveHeading;
+
+    renderHeadings();
+}
+
+module.exports = { renderOutlinePanel };

src/styles-concreteinfo.css

@@ -1,7 +1,7 @@
 /**
  * ConcreteInfo Theme for MarkdownConverter
  * Based on logo palette: #464646, #9a9696, #e5461f, #e3e3e3, #0d0b09
- * Version: 3.0.0
+ * Version: 4.1.0
  */
 
 /* ============================================

src/styles-modern.css

@@ -2346,3 +2346,280 @@ body[class*="dark"] .breadcrumb-bar {
     font-size: 14px;
     cursor: pointer;
 }
+
+/* Writing Analytics Modal */
+.analytics-overlay { position:fixed; inset:0; background:rgba(0,0,0,0.5); backdrop-filter:blur(4px); display:flex; align-items:center; justify-content:center; z-index:10000; animation:analyticsFadeIn 0.2s ease; }
+.analytics-modal { background:var(--bg-primary,#fff); border-radius:12px; width:520px; max-height:80vh; overflow-y:auto; box-shadow:0 20px 60px rgba(0,0,0,0.3); animation:analyticsSlideUp 0.3s ease; }
+.analytics-header { display:flex; justify-content:space-between; align-items:center; padding:20px 24px; border-bottom:1px solid var(--border-color,#e5e7eb); }
+.analytics-header h2 { margin:0; font-size:18px; font-weight:600; color:var(--text-primary); }
+.analytics-close { background:none; border:none; font-size:24px; cursor:pointer; color:var(--text-muted); padding:4px 8px; border-radius:4px; }
+.analytics-close:hover { background:var(--bg-tertiary); color:var(--text-primary); }
+.analytics-body { padding:16px 24px 24px; }
+.analytics-section { margin-bottom:20px; }
+.analytics-section h3 { font-size:12px; font-weight:600; text-transform:uppercase; letter-spacing:0.05em; color:var(--text-muted,#9ca3af); margin:0 0 10px; }
+.analytics-row { display:flex; justify-content:space-between; align-items:baseline; padding:6px 0; font-size:14px; }
+.analytics-label { color:var(--text-secondary,#6b7280); }
+.analytics-value { font-weight:500; color:var(--text-primary); }
+.analytics-value small { color:var(--text-muted); font-weight:400; margin-left:6px; }
+.readability-meter { height:4px; background:var(--bg-tertiary,#f3f4f6); border-radius:2px; margin-top:8px; overflow:hidden; }
+.readability-fill { height:100%; background:linear-gradient(90deg,#ef4444,#f59e0b,#10b981); border-radius:2px; transition:width 0.5s ease; }
+.word-cloud { display:flex; flex-wrap:wrap; gap:8px; margin-top:8px; }
+.word-tag { background:var(--bg-tertiary,#f3f4f6); padding:4px 10px; border-radius:12px; font-size:13px; color:var(--text-secondary); }
+.word-tag small { opacity:0.5; font-size:10px; margin-left:2px; }
+.analytics-longest { flex-direction:column; gap:4px; }
+.analytics-sentence-preview { font-style:italic; font-size:13px; color:var(--text-secondary); font-weight:400; }
+@keyframes analyticsFadeIn { from{opacity:0} to{opacity:1} }
+@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/styles-sidebar.css

@@ -276,3 +276,29 @@ body[class*="dark"] .tree-item:hover,
 body[class*="dark"] .git-file:hover {
     background: #333;
 }
+
+/* Outline Panel */
+.outline-panel { display: flex; flex-direction: column; height: 100%; }
+.outline-list { flex: 1; overflow-y: auto; padding: 4px 0; }
+.outline-item { display: flex; align-items: center; justify-content: space-between; padding: 4px 12px; cursor: pointer; font-size: 13px; color: var(--text-secondary, #6b7280); transition: background 0.15s, color 0.15s; border-left: 2px solid transparent; }
+.outline-item:hover { background: var(--bg-tertiary, #f3f4f6); color: var(--text-primary, #1f2937); }
+.outline-item.active { color: var(--accent-blue, #3b82f6); background: rgba(59, 130, 246, 0.08); border-left-color: var(--accent-blue, #3b82f6); font-weight: 600; }
+.outline-level-1 { padding-left: 12px; }
+.outline-level-2 { padding-left: 24px; }
+.outline-level-3 { padding-left: 36px; }
+.outline-level-4 { padding-left: 48px; }
+.outline-level-5 { padding-left: 56px; }
+.outline-level-6 { padding-left: 64px; }
+.outline-text { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.outline-badge { font-size: 10px; opacity: 0.5; margin-left: 8px; flex-shrink: 0; }
+.outline-empty { display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 32px 16px; color: var(--text-muted, #9ca3af); text-align: center; }
+.outline-empty p { margin: 4px 0; }
+.outline-hint { font-family: monospace; font-size: 12px; opacity: 0.7; }
+.outline-footer { padding: 8px 12px; border-top: 1px solid var(--border-color, #e5e7eb); font-size: 11px; color: var(--text-muted, #9ca3af); }
+
+/* Outline dark mode */
+body[class*="dark"] .outline-item { color: #9ca3af; }
+body[class*="dark"] .outline-item:hover { background: #374151; color: #e5e7eb; }
+body[class*="dark"] .outline-item.active { color: #8b9aff; background: rgba(139, 154, 255, 0.1); border-left-color: #8b9aff; }
+body[class*="dark"] .outline-empty { color: #6b7280; }
+body[class*="dark"] .outline-footer { border-color: #333; color: #6b7280; }

src/styles-zen.css

@@ -0,0 +1,102 @@
+/* Zen Mode — Distraction-free writing styles */
+
+/* Hide chrome elements */
+body.zen-mode .app-header,
+body.zen-mode .tab-bar,
+body.zen-mode .toolbar,
+body.zen-mode .status-bar,
+body.zen-mode .sidebar,
+body.zen-mode .breadcrumb-bar {
+    display: none !important;
+}
+
+/* Main content fills viewport */
+body.zen-mode .main-content {
+    height: 100vh;
+    overflow: hidden;
+}
+
+/* Editor container takes full width */
+body.zen-mode .editor-container {
+    width: 100% !important;
+    height: 100% !important;
+}
+
+/* Hide preview panes */
+body.zen-mode .preview-container,
+body.zen-mode .preview-pane,
+body.zen-mode .pane-resizer {
+    display: none !important;
+}
+
+/* Center and style editor content for comfortable reading width */
+body.zen-mode .cm-content {
+    max-width: 700px;
+    margin: 0 auto;
+    font-size: 18px;
+    line-height: 1.8;
+    padding-top: 80px;
+}
+
+body.zen-mode .cm-line {
+    padding: 4px 0;
+}
+
+body.zen-mode .editor-wrapper {
+    display: flex;
+    justify-content: center;
+}
+
+/* Floating HUD pill */
+.zen-hud {
+    position: fixed;
+    bottom: 24px;
+    left: 50%;
+    transform: translateX(-50%);
+    background: rgba(0, 0, 0, 0.6);
+    backdrop-filter: blur(12px);
+    -webkit-backdrop-filter: blur(12px);
+    color: rgba(255, 255, 255, 0.8);
+    padding: 10px 24px;
+    border-radius: 24px;
+    font-size: 13px;
+    font-family: 'Plus Jakarta Sans', system-ui, sans-serif;
+    z-index: 9999;
+    pointer-events: none;
+    display: flex;
+    align-items: center;
+    gap: 16px;
+    transition: opacity 0.3s ease;
+}
+
+.zen-hud-stat {
+    opacity: 0.7;
+}
+
+.zen-hud-sep {
+    opacity: 0.3;
+    margin: 0 4px;
+}
+
+/* Word goal progress bar */
+.zen-progress-container {
+    width: 120px;
+    height: 4px;
+    background: rgba(255, 255, 255, 0.15);
+    border-radius: 2px;
+    margin-top: 8px;
+    overflow: hidden;
+    display: none;
+}
+
+.zen-progress-bar {
+    height: 100%;
+    background: rgba(255, 178, 70, 0.85);
+    border-radius: 2px;
+    transition: width 0.3s ease;
+}
+
+/* Dark mode — HUD stays dark in both themes */
+body[class*="dark"].zen-mode .zen-hud {
+    background: rgba(0, 0, 0, 0.7);
+}