diff --git a/docs/superpowers/specs/2026-06-06-phase-10-polish-design.md b/docs/superpowers/specs/2026-06-06-phase-10-polish-design.md
new file mode 100644
index 0000000..f709c30
--- /dev/null
+++ b/docs/superpowers/specs/2026-06-06-phase-10-polish-design.md
@@ -0,0 +1,340 @@
+# Phase 10 — Polish + Delete Legacy Design
+
+> Companion to the parent plan: `docs/superpowers/plans/2026-06-05-react-ui-redesign.md` (Phase 10 is sketched at high level; this spec locks architecture, file map, deletion targets, and version strategy.)
+
+**Date:** 2026-06-06
+**Phase:** 10 of 10 (React + shadcn/ui UI redesign) — **FINAL**
+**Tag (on completion):** `v5.0.0` (the first release tag, all prior phases were `phase-N-*` working tags)
+
+---
+
+## 1. Goal & Non-Goals
+
+**Goal:** Finalize the React UI redesign. Decompose the legacy 146KB `src/main.js` into a feature-first modular structure under `src/main/`, remove the legacy vanilla-JS renderer and all dead IPC bridges, then ship **v5.0.0** with a CHANGELOG.
+
+**Non-goals (Phase 10):**
+- Adding new features (Phases 1-9 shipped all of them)
+- A full main-process test suite (the existing main process is largely untested; adding tests is Phase 11+)
+- Backwards compat shims for the legacy renderer
+- Renderer-side refactor (already done)
+- Migrating the renderer build pipeline further (vite configs are in place)
+
+**Success criteria:**
+- `src/main.js` is gone; `src/main/index.js` is the new entrypoint
+- `package.json#main` points to `src/main/index.js`
+- All 12 legacy renderer files are deleted
+- All 9 dead IPC channels are removed from `preload.js` and `main.js`
+- `src/index.html` is reduced to ~50 lines (just the Vite bootstrap)
+- `package.json#version` is `5.0.0`
+- `CHANGELOG.md` exists in Keep a Changelog 1.1.0 format
+- `git grep -E "renderer\.js|command-palette|print-preview|welcome\.js|zen-mode|wordTemplate|ascii-generator|table-generator|styles\.css"` returns zero results
+- All 305 tests still pass
+- `npx vite build --config vite.renderer.config.ts` succeeds
+- `npx electron .` launches and main window renders
+- Tag `v5.0.0` pushed to origin
+
+---
+
+## 2. Target Architecture
+
+### 2.1 `src/main/` (feature-first decomposition)
+
+```
+src/main/
+├── index.js              # entrypoint: bootstraps store, app, window, ipc
+├── store.js              # electron-store wrapper (preferences + wordTemplatePath)
+├── ipc.js                # ipcMain.handle registration (composes from modules)
+├── files/
+│   ├── index.js          # file ops facade (read/write/list/pickFolder/pickFile)
+│   ├── search.js         # recursive regex search (used by find-in-files)
+│   ├── git.js            # git status porcelain parser
+│   └── binary.js         # writeBuffer helper (Uint8Array → file)
+├── menu/
+│   ├── index.js          # buildMenu() — composes the app menu
+│   └── items.js          # individual menu items (File, Edit, View, etc.)
+├── window/
+│   ├── index.js          # createMainWindow ONLY (createAsciiWindow/createTableWindow are DEAD)
+│   └── state.js          # window state persistence
+├── word-template/
+│   ├── index.js          # WordTemplateExporter facade
+│   ├── parser.js         # .dotx parsing
+│   ├── converter.js      # markdown → docx
+│   └── apply.js          # apply template styles to converted docx
+└── utils/
+    ├── paths.js          # path helpers
+    ├── logger.js         # structured logging
+    └── download.js       # tool downloader
+```
+
+**Module rules:**
+- Each file has one clear responsibility (no god files; CLAUDE.md says >300 lines is the cap)
+- `index.js` is the public face of a folder; deeper files are private
+- `src/main/index.js` (top-level) wires everything together
+- Cross-folder imports go through `index.js`, not directly to internals
+
+### 2.2 Entry point change
+
+**Before:**
+```json
+// package.json
+"main": "src/main.js"
+```
+
+**After:**
+```json
+// package.json
+"main": "src/main/index.js"
+```
+
+The new `src/main/index.js` runs the same `app.whenReady().then(...)` flow that the current `src/main.js` does, but composes the decomposed modules.
+
+### 2.3 What becomes dead code (removed during decomposition)
+
+When the legacy renderer files are deleted, these main-process functions become orphaned and are removed too:
+
+| Function | File | Why dead |
+|---|---|---|
+| `createAsciiWindow()` | `src/main/window/index.js` | Loads deleted `src/ascii-generator.html` |
+| `createTableWindow()` | `src/main/window/index.js` | Loads deleted `src/table-generator.html` |
+| `ipcMain.on('open-ascii-generator', ...)` | `src/main/index.js` (after decomposition) | Replaced by React `<AsciiGeneratorDialog>` |
+| `ipcMain.on('open-table-generator', ...)` | `src/main/index.js` (after decomposition) | Replaced by React `<TableGeneratorDialog>` |
+| `webContents.send('print-preview')` | `src/main/menu/items.js` | Replaced by React `<PrintPreview>` |
+| `webContents.send('print-preview-styled')` | `src/main/menu/items.js` | Replaced by React `<PrintPreview>` |
+| `webContents.send('toggle-command-palette')` | `src/main/menu/items.js` | Replaced by `useCommandStore` |
+| `require('./wordTemplateExporter')` | `src/main/index.js` (after decomposition) | Replaced by `src/main/word-template/` + renderer-side `lib/docx-export.ts` |
+
+---
+
+## 3. Legacy Deletion Map
+
+### 3.1 Files to delete from `src/` (12 files, ~14,426 lines)
+
+| File | Size | Lines | Replaced by |
+|---|---|---|---|
+| `src/renderer.js` | 213KB | 5319 | `src/renderer/` (Phases 1-9) |
+| `src/styles.css` | 74KB | 3723 | `src/renderer/index.css` + Tailwind |
+| `src/styles-modern.css` | 71KB | 2625 | Tailwind + shadcn/ui |
+| `src/styles-concreteinfo.css` | 21KB | 969 | Tailwind theme tokens |
+| `src/styles-sidebar.css` | 9.7KB | 304 | `<Sidebar>` component |
+| `src/styles-zen.css` | 2.1KB | 102 | Zen mode in AppShell |
+| `src/styles-welcome.css` | 2.2KB | 24 | Welcome dialog |
+| `src/fonts.css` | 1.8KB | (imported elsewhere) | Tailwind font config |
+| `src/command-palette.js` | (small) | 109 | `useCommandStore` |
+| `src/print-preview.js` | (small) | 138 | `<PrintPreview>` |
+| `src/welcome.js` | (small) | 78 | `<Welcome>` modal |
+| `src/zen-mode.js` | (small) | 292 | `use-zen-mode` hook + AppShell |
+| `src/wordTemplateExporter.js` | (small) | 743 | `src/main/word-template/` + renderer `lib/docx-export.ts` |
+| `src/ascii-generator.html` | 34KB | (HTML) | `<AsciiGeneratorDialog>` |
+| `src/table-generator.html` | 18KB | (HTML) | `<TableGeneratorDialog>` |
+
+**Total: 12 JS/CSS/HTML files = 14,426 lines / ~445KB**
+
+Note: `src/index.html` is **NOT** deleted — it's rewritten to a minimal Vite bootstrap (~50 lines). See §4.
+
+### 3.2 Dead IPC channels to remove from `src/preload.js`
+
+- `toggle-command-palette` (line 238)
+- `open-ascii-generator` (line 89)
+- `open-table-generator` (line 92)
+- `print-preview` (line 173)
+- `print-preview-styled` (line 174)
+- `show-table-generator` (line 180)
+- `show-ascii-generator-window` (line 217)
+- `show-ascii-generator` (line 218)
+- `show-table-generator-window` (line 221)
+
+And from the exposed API surface:
+- `openAscii: () => ipcRenderer.send('open-ascii-generator')` (line 445)
+- `openTable: () => ipcRenderer.send('open-table-generator')` (line 446)
+
+**9 channel names + 2 API entries to remove.**
+
+### 3.3 Legacy references in `src/index.html` (16 places)
+
+- `<link rel="stylesheet" href="styles.css">` (line ~6)
+- `<link rel="stylesheet" href="styles-welcome.css">` (line ~7)
+- `<div id="print-preview-overlay" class="modal hidden" ...>` block (~10 lines)
+- `<div class="command-palette-overlay hidden" id="command-palette-overlay">` block (~5 lines)
+- `<script src="renderer.js"></script>` (final script tag)
+
+**All of these are removed. The rewritten `src/index.html` is just:**
+```html
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Markdown Converter</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/renderer/main.tsx"></script>
+  </body>
+</html>
+```
+
+(Confirm exact entrypoint path with `src/renderer/` structure; this is the standard Vite + React 19 shape.)
+
+### 3.4 Main process rewiring
+
+- Remove `require('./wordTemplateExporter')` from main entrypoint
+- Remove `webContents.send('print-preview*')` and `webContents.send('toggle-command-palette')` from menu items
+- Remove `ipcMain.on('open-ascii-generator', ...)` and `ipcMain.on('open-table-generator', ...)` handlers
+- Remove `asciiGeneratorWindow` and `tableGeneratorWindow` global state (and any references to `loadFile(...ascii-generator.html)` / `loadFile(...table-generator.html)`)
+
+---
+
+## 4. `src/index.html` Rewrite
+
+The current `src/index.html` is 1667 lines of legacy markup. The new version is minimal:
+
+```html
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Markdown Converter</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/renderer/main.tsx"></script>
+  </body>
+</html>
+```
+
+Vite handles the rest. The renderer's `<App />` is mounted in `main.tsx` which is the Vite entrypoint.
+
+---
+
+## 5. Version Bump + CHANGELOG
+
+### 5.1 `package.json`
+
+```diff
+-  "version": "4.4.2",
++  "version": "5.0.0",
+```
+
+Major version bump because the legacy renderer removal is a breaking change for anyone who had plugins/integrations pointing at `src/renderer.js`.
+
+### 5.2 `CHANGELOG.md` (new file, Keep a Changelog 1.1.0 format)
+
+```markdown
+# Changelog
+
+All notable changes to markdown-converter will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [5.0.0] - 2026-06-06
+
+### Added
+- **Complete React 19 + Vite + TypeScript renderer** replacing the legacy vanilla-JS UI
+- Native macOS/Windows/Linux menus with command palette and keyboard shortcuts
+- Settings sheet (5 tabs: editor, theme, keybindings, advanced, about)
+- Modal layer with 13 modal kinds (export PDF/DOCX/HTML/Word, batch, settings, about, welcome, confirm, ASCII gen, table gen, find in files)
+- 10 advanced tools: ASCII generator, table generator, Word export, find-in-files, REPL, print preview, zen mode, minimap, breadcrumbs-with-symbols, git status
+- Sonner toast notifications at 4 wire points
+- 3 mount strategies: ModalLayer dialogs, App.tsx overlays, editor/sidebar integrations
+- `ipc.file.writeBuffer` for renderer-side binary output
+- `ipc.file.search` (recursive regex), `ipc.file.gitStatus`, `ipc.print.show`, `ipc.app.showSaveDialog`
+- 305 unit + integration tests (vitest + React Testing Library)
+- Per-package @radix-ui primitives
+- shadcn/ui (new-york style) primitives
+
+### Changed
+- **BREAKING**: Renderer is now React-only.
+- Main process decomposed from 146KB `src/main.js` into feature-first modules under `src/main/`
+- `src/index.html` reduced from 1667 to ~50 lines
+- IPC contract: handlers throw, `safeCall` catches → `{ ok, error }`
+- Settings store: `useSettingsStore` (zustand persist with zod)
+- Modal state: `useAppStore.modal: ModalState` discriminated union
+
+### Removed
+- `src/renderer.js` (legacy vanilla-JS renderer, 5319 lines)
+- 7 legacy stylesheets (styles.css, styles-modern.css, styles-concreteinfo.css, styles-sidebar.css, styles-zen.css, styles-welcome.css, fonts.css)
+- 5 legacy scripts (command-palette.js, print-preview.js, welcome.js, zen-mode.js, wordTemplateExporter.js)
+- 2 legacy HTMLs (ascii-generator.html, table-generator.html)
+- 9 dead IPC channels (toggle-command-palette, open-*/show-* ascii/table, print-preview*)
+```
+
+---
+
+## 6. Task Decomposition
+
+**10 tasks** (each independently verifiable, one feature per commit, no bundling):
+
+1. **Decompose main.js — `src/main/files/`** (file ops facade, search, git, binary)
+2. **Decompose main.js — `src/main/menu/`** (buildMenu + items, with dead sends removed)
+3. **Decompose main.js — `src/main/window/`** (createMainWindow ONLY — ascii/table windows removed)
+4. **Decompose main.js — `src/main/word-template/`** (WordTemplateExporter split into parser/converter/apply)
+5. **Decompose main.js — `src/main/utils/` + `store.js` + `ipc.js` + `index.js`** (glue + new entrypoint)
+6. **Trim preload.js** — remove 9 dead IPC channels + 2 exposed API entries
+7. **Delete legacy renderer files** (12 files: renderer.js, 7 styles, fonts.css, 4 scripts, 2 htmls)
+8. **Rewrite src/index.html** — minimal Vite bootstrap (~50 lines)
+9. **Bump package.json version to 5.0.0 + write CHANGELOG.md**
+10. **Final verification + tag v5.0.0** (build, tests, grep, electron smoke)
+
+Tasks 1-5 are subagent-driven (decomposition is mechanical given a clear target structure). Tasks 6-9 are direct edits. Task 10 is a verification gate.
+
+---
+
+## 7. Verification Strategy
+
+**Per task:**
+- After each decomposition step: `npx vitest run` (305 still green)
+- After main.js decomposition: `npx electron .` smoke — app starts, opens a file
+- After deletions: `git grep -E "renderer\.js|command-palette|print-preview|welcome\.js|zen-mode|wordTemplate|ascii-generator|table-generator|styles\.css"` returns ZERO results
+
+**Final (Task 10):**
+- `npx vitest run` — 305 passing
+- `npx vite build --config vite.renderer.config.ts` — succeeds
+- `npx vite build --config vite.preload.config.ts` — succeeds
+- `npx electron .` — app launches, main window renders
+- Manual smoke: open a `.md` file, edit it, export to PDF/DOCX, use the command palette
+- `git tag -a v5.0.0 -m "..."` and `git push origin v5.0.0`
+
+---
+
+## 8. Risks & Open Questions
+
+**Risks:**
+- **Decomposition regressions.** Splitting a 146KB main.js into 7+ files has surface area for missed imports / circular deps. Mitigation: tests stay green; electron smoke after each step.
+- **Hidden legacy references.** `git grep` won't catch references inside minified bundles or in node_modules. Mitigation: vite build will fail if there's a dangling import.
+- **`src/main/index.js` entrypoint change.** Anything in the build pipeline (electron-builder, scripts) that hardcodes `src/main.js` needs to be updated. Mitigation: grep all of `package.json`, `scripts/`, `vite.*.config.ts` for `main.js`.
+
+**Open questions (resolved during brainstorming):**
+- ~~Main process scope~~ → Full rewrite
+- ~~Folder shape~~ → Feature-first
+- ~~IPC migration~~ → Delete dead channels
+- ~~Version strategy~~ → v5.0.0 with Keep a Changelog format
+- ~~Order of work~~ → Decompose first, delete last
+
+---
+
+## 9. Out of Scope (deferred to Phase 11+)
+
+- Main process test suite
+- Renderer-side further refactor
+- New features
+- Migration to tauri (separate plan in `docs/plans/2026-03-15-react-tauri-pwa.md`)
+
+---
+
+## 10. Success Criteria
+
+Phase 10 is complete when:
+- All 10 tasks are committed, one per commit, no bundling
+- `src/main/index.js` is the new entrypoint
+- All 12 legacy files are deleted
+- All 9 dead IPC channels are removed
+- `package.json#version` is `5.0.0`, `package.json#main` is `src/main/index.js`
+- `CHANGELOG.md` exists with a complete v5.0.0 entry
+- 305 tests still pass
+- `npx vite build` succeeds for both renderer and preload configs
+- `npx electron .` launches and the app works end-to-end
+- `git grep` for legacy references returns zero results
+- Tag `v5.0.0` is created and pushed to origin
+- Phase 10 is the LAST phase of the React UI redesign