# Reduced Motion Support

## Objective

Respect people who asked their device for less animation.

An app-wide motion setting driven by the system preference, with an in-app override and legible non-animated alternatives.

## 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. Audit every animation in the app — transitions, parallax, auto-advancing carousels, looping loaders, shimmer, confetti, scroll effects, chart entry animations — and list which are decorative and which carry meaning.
2. Route all motion through one place, so the preference is applied once rather than remembered per component.
3. Default to the operating system's prefers-reduced-motion setting and let the user override it in settings, because the OS setting is often wrong for a shared or managed machine. Persist the override.
4. Replace removed motion with something that still communicates the change: an instant state swap plus a colour or position change, a short cross-fade, or a message. The point is less motion, not less feedback.
5. Apply the preference to third-party components, charts, embedded video, and animated images by disabling their animation options where the library exposes one.
6. Do NOT simply set all animation durations to zero globally. Elements will teleport, panels will appear with no indication of where they came from, and the result disorients the same users the setting was meant to help.

## 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

- Reduced motion does not mean no opacity change — small cross-fades are generally safe and preserve continuity.
- Autoplaying and looping media must not start under reduced motion, and needs a visible play control instead.
- Loading indicators that rely on spin need a static or text alternative, or the user loses all sense of progress.
- The preference can change while the app is open; listen for the change rather than reading it once at boot.
- Scroll-triggered reveals must leave content visible when motion is off, not permanently hidden at zero opacity.
- Toasts and drawers that slide in should still appear and disappear distinctly enough to be noticed without the slide.
- Test with the setting on. Most reduced-motion bugs are elements that simply never become visible.

## 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

- [ ] Every animation in the app is covered by the motion setting.
- [ ] The setting defaults to prefers-reduced-motion and can be overridden in-app, with the choice persisted.
- [ ] A change in the system preference is picked up without a reload.
- [ ] Removed animations are replaced by a legible alternative, not by an abrupt jump.
- [ ] No content is left invisible or unreachable when motion is disabled.
- [ ] Autoplaying and looping media do not start under reduced motion.
- [ ] Third-party components and charts honour the setting where they allow it.
- [ ] 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.