diff --git a/.gitignore b/.gitignore
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--- a/.gitignore
+++ b/.gitignore
@@ -13,6 +13,9 @@ node_modules
 logs
 *.log
 
+# Brainstorming mockups
+.superpowers
+
 # Misc
 .DS_Store
 .fleet
diff --git a/docs/superpowers/specs/2026-05-15-registration-page-design.md b/docs/superpowers/specs/2026-05-15-registration-page-design.md
new file mode 100644
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@@ -0,0 +1,88 @@
+# Registration Page Design
+
+## Overview
+
+Add a registration page at `/register` with username, password, confirm password, and SVG captcha. On success, redirect to `/login` with a query param. Login page is out of scope.
+
+## Stack
+
+- Nuxt 4.4 + Nuxt UI 4.6 + Tailwind v4
+- Drizzle ORM + SQLite (users table already exists)
+- bcryptjs (already installed), svg-captcha, zod (already installed)
+
+## Files
+
+### New
+
+| File | Purpose |
+|---|---|
+| `app/pages/register.vue` | Registration page component |
+| `server/api/auth/captcha.get.ts` | Generate SVG captcha, return token + svg |
+| `server/api/auth/register.post.ts` | Validate input, create user |
+| `server/utils/auth/captcha.ts` | Server-side captcha generation/validation |
+| `server/utils/auth/validation.ts` | Zod schemas for registration input |
+
+### Modified
+
+| File | Change |
+|---|---|
+| `app/layouts/default.vue` | Wire header button to `/register` |
+
+## API Endpoints
+
+### GET /api/auth/captcha
+
+Generates a captcha, stores token→text in a server-side Map (5-min expiry), returns the SVG and token.
+
+```
+Response: { code: 0, data: { token: "uuid", svg: "<svg>...</svg>" } }
+```
+
+### POST /api/auth/register
+
+```
+Request:  { username, password, confirmPassword, captchaToken, captchaText }
+Response: { code: 0, data: { id: 1, username: "foo" } }
+```
+
+Steps:
+1. Zod validation (username 3-30, password 8+, passwords match)
+2. Verify captcha: lookup token in Map, compare text case-insensitive, delete on match
+3. Check username uniqueness in DB
+4. bcryptjs hash password (salt rounds 10)
+5. Insert into users table with role="user", status="active"
+6. Return success — no auto-login
+
+## Data Flow
+
+1. Page mounts → GET /api/auth/captcha → render SVG
+2. User submits → client Zod validation → POST /api/auth/register
+3. On success → `navigateTo('/login?registered=1')`
+4. On error → show toast, keep form state; if captcha fail, auto-refresh captcha
+
+## Error Handling
+
+Client-side: UForm + Zod validation for empty fields, length, password match.
+
+Server-side:
+
+| Case | Message |
+|---|---|
+| Zod validation fail | "密码至少需要8个字符" |
+| Captcha wrong | "验证码错误" |
+| Captcha expired | "验证码已过期" |
+| Username taken | "用户名已存在" |
+| Server error | "注册失败，请稍后重试" |
+
+Captcha is consumed (deleted from Map) on match to prevent replay. If registration fails after captcha check, a new captcha is fetched.
+
+## Form Fields
+
+- **Username** — required, 3-30 characters, unique in DB
+- **Password** — required, min 8 characters, masked input with toggle
+- **Confirm Password** — required, must match password
+- **Captcha** — SVG image + text input, refresh button
+
+## Layout
+
+Card-centered form (380px max-width), single column. Header already has the "登录/注册" button. Form shows a "Already have an account? Log in" link at the bottom.