diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
new file mode 100644
index 0000000..98df68a
--- /dev/null
+++ b/.github/workflows/deploy.yml
@@ -0,0 +1,44 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: false
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - run: npm ci
+
+      - run: npm test
+
+      - run: npm run build
+
+      - uses: actions/configure-pages@v5
+
+      - uses: actions/upload-pages-artifact@v3
+        with:
+          path: dist
+
+      - id: deployment
+        uses: actions/deploy-pages@v4
diff --git a/CLAUDE.md b/CLAUDE.md
index 583e3ad..7919dd4 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -12,7 +12,7 @@ npm run test:watch   # Run tests in watch mode
 npx vitest run src/fruits.test.js   # Run a single test file
 ```
 
-No vite.config or vitest.config files — both use defaults.
+`vite.config.js` sets `base` for GitHub Pages deployment. No vitest.config — uses defaults.
 
 ## Architecture
 
diff --git a/specs/feat-github-pages-deploy.md b/specs/feat-github-pages-deploy.md
new file mode 100644
index 0000000..8b7a292
--- /dev/null
+++ b/specs/feat-github-pages-deploy.md
@@ -0,0 +1,160 @@
+# GitHub Actions: Deploy to GitHub Pages
+
+## Status
+Draft
+
+## Authors
+Claude Code — 2026-04-12
+
+## Overview
+Add a GitHub Actions workflow to automatically build and deploy the Suika game to GitHub Pages on every push to `main`. This gives the game a publicly accessible URL with zero hosting cost.
+
+## Background / Problem Statement
+The game currently has no deployment pipeline. To share or play it, someone must clone the repo and run `npm run dev` locally. GitHub Pages is the natural fit: the repo is already hosted on GitHub (`tiennm99/try-claudekit`), the game is a static Vite build, and Pages is free for public repos.
+
+## Goals
+- Automated deploy on every push to `main`
+- Game accessible at `https://tiennm99.github.io/try-claudekit/`
+- Build failures block deployment (no broken deploys)
+- Run existing tests before deploying
+
+## Non-Goals
+- Custom domain setup
+- Preview deployments for pull requests
+- CDN or caching configuration beyond GitHub Pages defaults
+- Server-side rendering or API routes
+
+## Technical Dependencies
+- **GitHub Actions** — built-in CI/CD, no external service needed
+- **actions/configure-pages** / **actions/upload-pages-artifact** / **actions/deploy-pages** — official GitHub Pages deployment actions
+- **Vite** (already in devDeps) — needs `base` config for subdirectory hosting
+
+## Detailed Design
+
+### 1. Vite Base Path Configuration
+
+GitHub Pages serves this repo at `/try-claudekit/`, so asset paths must be prefixed. Create a minimal `vite.config.js`:
+
+```js
+import { defineConfig } from "vite";
+
+export default defineConfig({
+  base: "/try-claudekit/",
+});
+```
+
+This affects only production builds (`npm run build`). Dev server (`npm run dev`) ignores `base` for local paths.
+
+### 2. GitHub Actions Workflow
+
+Create `.github/workflows/deploy.yml`:
+
+```yaml
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch: # allow manual trigger
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: pages
+  cancel-in-progress: false
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - run: npm ci
+
+      - run: npm test
+
+      - run: npm run build
+
+      - uses: actions/configure-pages@v5
+
+      - uses: actions/upload-pages-artifact@v3
+        with:
+          path: dist
+
+      - id: deployment
+        uses: actions/deploy-pages@v4
+```
+
+### 3. File Changes Summary
+
+| File | Change |
+|------|--------|
+| `vite.config.js` (new) | Set `base: "/try-claudekit/"` |
+| `.github/workflows/deploy.yml` (new) | Build + test + deploy workflow |
+
+### 4. GitHub Repository Setting
+
+GitHub Pages source must be set to **"GitHub Actions"** (not branch-based). This is a one-time manual step in repo Settings > Pages > Source.
+
+## User Experience
+- **Developers**: Push to `main` triggers automatic deployment. Build/test failures show in the Actions tab and block deploy.
+- **Players**: Visit `https://tiennm99.github.io/try-claudekit/` to play. No install required.
+- **Manual trigger**: The `workflow_dispatch` event allows re-deploying from the Actions tab without a new commit.
+
+## Testing Strategy
+
+### Pre-deploy gate
+The workflow runs `npm test` before building. If any test fails, the job stops and nothing is deployed.
+
+### Verification after implementation
+- Push a commit to `main` and confirm the Actions run completes successfully
+- Visit the Pages URL and verify the game loads and is playable
+- Verify asset paths resolve correctly (no 404s for JS/CSS bundles)
+- Test that a failing test prevents deployment by temporarily breaking a test
+
+### Local validation
+- Run `npm run build` locally and serve `dist/` with `npx vite preview` to verify the base path works
+
+## Performance Considerations
+- Build is fast (~5s for a small Vite project). No caching beyond `npm ci` + Node module cache needed.
+- GitHub Pages serves with its own CDN. No additional optimization required for this scale.
+
+## Security Considerations
+- Workflow uses minimal permissions (`contents: read`, `pages: write`, `id-token: write`)
+- No secrets or tokens needed — Pages deployment uses OIDC via `id-token: write`
+- `concurrency` group prevents race conditions between overlapping deploys
+
+## Documentation
+- Update README or docs to include the live URL once deployed
+
+## Implementation Phases
+
+### Phase 1: Core (MVP)
+1. Create `vite.config.js` with `base` setting
+2. Create `.github/workflows/deploy.yml`
+3. Set GitHub Pages source to "GitHub Actions" in repo settings
+4. Push to `main` and verify deployment
+
+### Phase 2: Optional Enhancements (if desired later)
+- Add PR preview deployments
+- Add build status badge to README
+- Custom domain configuration
+
+## Open Questions
+- Should the repo name change in the future, the `base` path in `vite.config.js` must be updated to match. Consider using an environment variable if this is likely.
+
+## References
+- [Vite — Deploying to GitHub Pages](https://vite.dev/guide/static-deploy#github-pages)
+- [GitHub Actions — deploy-pages](https://github.com/actions/deploy-pages)
+- [GitHub Pages documentation](https://docs.github.com/en/pages)
diff --git a/vite.config.js b/vite.config.js
new file mode 100644
index 0000000..a0f61fc
--- /dev/null
+++ b/vite.config.js
@@ -0,0 +1,5 @@
+import { defineConfig } from "vite";
+
+export default defineConfig({
+  base: "/try-claudekit/",
+});