# Component Playground

## Objective

Render every component in isolation, in every state, with its props adjustable.

A development surface that renders each component on its own with controls for its props, themes, and states.

## Before You Begin

This feature is being added to an application that already exists and already
works. Do not scaffold a new project, and do not assume a blank slate.

Inspect the codebase first and establish:

- The existing application structure and where code of this kind already lives.
- The framework and version in use.
- The existing design system — colours, spacing, typography, and component conventions.
- Existing UI components you can reuse instead of writing new ones.
- The existing database structure, if this feature needs to persist anything.
- The existing authentication and authorization system, if this feature is user-scoped.
- Dependencies already installed, so you don't add a library that duplicates one.
- The existing test setup and conventions.

Only start writing code once you understand the above. If the application
already implements part of this feature, extend it rather than replacing it.

## Implementation Instructions

1. Render playground examples inside the same providers, theme, reset, and global styles the real application uses. A component that only looks right in the playground is a component whose playground is lying.
2. Give each component controls for its documented props, and derive the control list from the component's own definition so a new variant appears without anyone remembering to add it.
3. Cover the states that are hard to reach in the product: loading, empty, error, disabled, no-permission, and content far longer than the design assumed. Those are the states the playground exists for; the happy path is already visible in the app.
4. Include the theme and viewport switches in the playground itself, so light, dark, and narrow layouts can be checked without a build change.
5. Do not add branches to component code for the playground's benefit. A condition that changes behaviour when rendered outside the app means the thing being reviewed is not the thing that ships.

## UI and UX Requirements

Match the application's existing design system exactly. Reuse its components,
spacing, and typography. This feature should look like it was always there.

## Responsive Requirements

Works on mobile, tablet, and desktop. Touch targets are large enough to hit on a
phone, and nothing overflows horizontally at 320px.

## Accessibility Requirements

- Fully keyboard navigable.
- Correct semantic elements and ARIA roles.
- Visible focus states.
- Meets WCAG AA contrast.
- Dynamic changes are announced to screen readers.
- Respects prefers-reduced-motion.

## Edge Cases

- Examples must render through the application's real providers and styles. A playground with its own stripped-down wrapper hides exactly the theme, layout, and context problems it was built to catch.
- Loading, error, empty, and overlong-content states must each have an example. Those states reach users through paths that are awkward to reproduce in the running app, so they go unreviewed unless the playground forces them.
- No component may contain a code path that exists only for the playground. Test hooks, mocked data injected inside the component, and conditions keyed on the environment all mean the reviewed rendering is not the shipped one.
- Examples must stay aligned with the component's current props, and a renamed or removed prop must break the example loudly rather than silently rendering a default.
- Every component in the inventory should have at least one example, and the gap between the two lists should be visible, since the components without examples are usually the ones that need them.
- The playground must not become a route in the production build, and it must not require the production data sources to load.
- Fixture content should include text in a language with long compound words and a right-to-left script, because layouts break there first and never in the sample copy.

## Testing

Exercise the feature end to end in the running application. Cover every edge case
above, then run the existing test suite and confirm nothing regressed.

## Acceptance Criteria

- [ ] Examples render inside the application's real providers, theme, and global styles.
- [ ] Prop controls are derived from each component's definition rather than maintained by hand.
- [ ] Loading, error, empty, disabled, no-permission, and overlong-content states each have an example.
- [ ] No component contains a branch that exists only for the playground.
- [ ] Theme and viewport can be switched from within the playground.
- [ ] Components lacking an example are reported against the component inventory.
- [ ] The playground is absent from the production build and needs no production data source.
- [ ] The feature matches the existing design system.
- [ ] No existing functionality is broken.

## Adaptation Rules

- Match the existing design system. Do not introduce a new colour palette,
  spacing scale, or component library.
- Reuse existing components and utilities wherever they fit.
- Follow the naming, file layout, and code style already present.
- Do not upgrade, replace, or remove existing dependencies to make this
  feature fit. Adapt the feature to the app, not the app to the feature.
- Do not break existing functionality. If a change is genuinely required in
  existing code, make the smallest one that works and say so.
- If something in these instructions conflicts with how the application is
  built, follow the application and explain the deviation.

## Final Verification

Before you report the work as done:

1. Re-read the acceptance criteria above and check each one against what you
   actually built.
2. Run the application and exercise the feature end to end.
3. Run the existing test suite and confirm you have broken nothing.
4. Check the feature on mobile, tablet, and desktop widths.
5. Check keyboard navigation and focus handling.
6. Summarize what changed: files added, files modified, and anything you
   deliberately did differently because of how this application is built.

If any acceptance criterion is unmet, fix it before reporting completion.