---
name: building-ui-bundle-frontend
description: "MUST activate before editing ANY file under uiBundles/*/src/ for visual or UI changes to an EXISTING app — pages, components, sections, layout, styling, colors, fonts, navigation, animations, or any look-and-feel change. Use this skill when modifying pages, components, layout, styling, or navigation in an existing UI bundle app. Activate when the project contains appLayout.tsx, routes.tsx, src/pages/, src/components/, or global.css. This skill contains critical project-specific conventions (appLayout.tsx shell, shadcn/ui components, Tailwind CSS, Salesforce base-path routing, module restrictions) that override general knowledge. Without this skill, generated code will use wrong imports, break routing, or ignore project structure. Do NOT use when creating a new app from scratch (use building-ui-bundle-app instead)."
metadata:
  version: "1.0"
---

# UI Bundle UI

## Identify the Task

Determine which category the request falls into:

| Category | Examples | Implementation Guide |
|----------|----------|---------------------|
| **Page** | New routed page (contacts, dashboard, settings) | `implementation/page.md` |
| **Header / Footer** | Site-wide nav bar, footer, branding | `implementation/header-footer.md` |
| **Component** | Widget, card, table, form, dialog | `implementation/component.md` |

---

## Layout and Navigation

`appLayout.tsx` is the source of truth for navigation and layout. Every page shares this shell.

When making any change that affects navigation, header, footer, sidebar, theme, or layout:

1. Edit `src/appLayout.tsx` — the layout used by `routes.tsx`
2. Replace all default/template nav items and labels with app-specific links and names
3. Replace placeholder app name everywhere: header, nav brand, footer, `<title>` in `index.html`

Before finishing, confirm: Did I update `appLayout.tsx` with real nav items and branding?

| What | Where |
|------|-------|
| Layout, nav, branding | `src/appLayout.tsx` |
| Document title | `index.html` |
| Root page content | Component at root route in `routes.tsx` |

---

## React and TypeScript Standards

### Routing

Use a single router package. With `createBrowserRouter` / `RouterProvider`, all imports must come from `react-router` (not `react-router-dom`).

If the app uses a client-side router (React Router, Remix Router, Vue Router, etc.), always derive basename / basepath / base from the document's `<base href>` tag at runtime. Never hardcode the basename:

```js
const basename = document.querySelector('base')
  ? new URL(document.querySelector('base').href).pathname.replace(/\/$/, '')
  : '/';
const router = createBrowserRouter(routes, { basename });
```

### Component Library and Styling

- **shadcn/ui** for components: `import { Button } from '@/components/ui/button';`
- **Tailwind CSS** utility classes

### URL and Path Handling

Apps run behind dynamic base paths. Router navigation (`<Link to>`, `navigate()`) uses absolute paths (`/x`). Non-router attributes (`<img src>`) use dot-relative (`./x`). Prefer Vite `import` for static assets.

### TypeScript

- Never use `any` — use proper types, generics, or `unknown` with type guards
- Event handlers: `(event: React.FormEvent<HTMLFormElement>): void`
- State: `useState<User | null>(null)` — always provide the type parameter
- No unsafe assertions (`obj as User`) — use type guards instead

### Module Restrictions

React UI bundles must not import Salesforce platform modules like `lightning/*` or `@wire` (LWC-only). For data access, use the `using-ui-bundle-salesforce-data` skill.

---

## Design Thinking

Before coding, commit to a bold aesthetic direction:

- **Purpose:** What problem does this interface solve? Who uses it?
- **Tone:** Pick a clear direction — brutally minimal, maximalist, retro-futuristic, organic, luxury, playful, editorial, brutalist, art deco, soft/pastel, industrial. Use these as inspiration but design one true to the context.
- **Differentiation:** What makes this unforgettable? What's the one thing someone will remember?

Choose a clear conceptual direction and execute it with precision. Bold maximalism and refined minimalism both work — the key is intentionality, not intensity.

---

## Frontend Aesthetics

- **Typography:** Choose distinctive, characterful fonts. Pair a display font with a refined body font. Never default to Inter, Roboto, Arial, Space Grotesk, or system fonts.
- **Color:** Commit to a cohesive palette using CSS variables. Dominant colors with sharp accents outperform timid, evenly-distributed palettes. Avoid cliched purple gradients on white.
- **Motion:** Focus on high-impact moments — one well-orchestrated page load with staggered reveals (`animation-delay`) creates more delight than scattered micro-interactions. Use scroll-triggering and hover states that surprise. Prefer CSS-only solutions; use Motion library for React when available.
- **Spatial Composition:** Unexpected layouts — asymmetry, overlap, diagonal flow, grid-breaking elements. Generous negative space OR controlled density.
- **Backgrounds & Depth:** Create atmosphere rather than defaulting to solid colors. Gradient meshes, noise textures, geometric patterns, layered transparencies, dramatic shadows, decorative borders, grain overlays.

- **Mobile Responsiveness:** All generated UI MUST be mobile-responsive. Use Tailwind responsive prefixes (`sm:`, `md:`, `lg:`) to adapt layouts across breakpoints. Stack columns on small screens, use flexible grids, and ensure touch targets are at least 44px. Test that navigation, typography, and spacing work on mobile viewports.

Match implementation complexity to the aesthetic vision. Maximalist designs need elaborate animations and effects. Minimalist designs need restraint, precision, and careful spacing/typography. No two designs should look the same — vary themes, fonts, and aesthetics across generations.

---

## Clarifying Questions

Ask one question at a time and stop when you have enough context.

### For a Page
1. Name and purpose?
2. URL path?
3. Should it appear in navigation?
4. Access control? (public, authenticated via `PrivateRoute`, or unauthenticated via `AuthenticationRoute`)
5. Content sections? (list, form, table, detail view)
6. Data fetching needs?

### For a Header / Footer
1. Header, footer, or both?
2. Contents? (logo, nav links, user avatar, copyright, social icons)
3. Sticky header?
4. Color scheme or style direction?

### For a Component
1. What should it do?
2. Which page does it belong to?
3. Shared/reusable or specific to one feature?
4. Data or props needed?
5. Internal state? (loading, toggle, form state)
6. Specific shadcn components to use?

---

## Verification

Before completing, run lint and build from the UI bundle directory. Lint must result in 0 errors and build must succeed.
