Skeleton

# Aster Component Implementation Prompt — Skeleton

## 1. Component Purpose & Canonical Role
- **Component:** Skeleton (`skeleton`)
- **Category:** Data Display
- **Native Element:** `<div aria-hidden="true">`
- **Summary:** Placeholder shapes shown while content loads.
- **When to Use:** Initial card, list, or table loading states.
- **When Not to Use:** Fast interactions under 200ms.

## 2. Authoritative Repository Files
- **Component CSS:** `components/skeleton/skeleton.css`
- **Component Spec:** `docs/components/skeleton.md`
- **Agent Contract:** `skills/using-aster-components/SKILL.md`
- **Compiled Bundle:** `dist/css/aster.css` and `dist/js/aster.js`

## 3. Canonical HTML Structure & Classes
```html
<div aria-busy="true">
  <div class="as-skeleton as-skeleton--avatar" aria-hidden="true" style="width: 40px; height: 40px;"></div>
  <div class="as-skeleton as-skeleton--text" aria-hidden="true" style="width: 80%;"></div>
  <div class="as-skeleton as-skeleton--text" aria-hidden="true" style="width: 50%;"></div>
</div>
```

## 4. Measured Geometry
Measured from the rendered component when this page loads.

## 5. Non-Negotiable Aster Constraints
1. **Zero Primitive Color Leaks:** Bind colors strictly to `--as-semantic-color-*` custom properties. Never use `--as-color-primitive-*` or hardcoded hex values in component usage.
2. **Minimum 4px Radius Policy:** Never use `2px` border-radius. Use `--as-radius-sm` (`4px`), `--as-radius-md` (`8px`), `--as-radius-lg` (`12px`), or `--as-radius-full` (`9999px`).
3. **Single Standard Density Mode:** Compact mode (`data-density="compact"` / `.as-*--compact`) is permanently retired. Do not emit compact classes or attributes.
4. **WCAG 2.2 AA Accessibility:** Maintain >= 4.5:1 text contrast, >= 3:1 UI/border contrast, >= 24x24px interactive hit targets, and full keyboard operability (`Tab`, `Enter`, `Space`, `Escape`, Arrow keys).

## 6. Verification Commands
```bash
npm run test:components
npm run test:contrast
npm run test:browser
```