# Skip Links and Landmarks

## Objective

Let keyboard users jump past repeated navigation straight to the content.

A skip link at the top of the application shell plus a consistent set of landmark regions on every page.

## 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. Add a skip link as the first focusable element in the shell, hidden until focused and clearly visible when it is. Do not hide it with display:none — that removes it from the tab order and it will never be reachable.
2. Give it a target that exists on every route: the main content region, made focusable so activating the link actually moves focus rather than only scrolling.
3. Audit the shell's landmarks. There is exactly one main per page; header, footer, and primary navigation each appear once and wrap the right content.
4. Where navigation appears more than once — a global nav plus a sidebar plus in-page section links — give each an accessible name so a screen reader's landmark list distinguishes them.
5. Reveal the skip link with an overlay or transform rather than by inserting it into the flow, so the page does not jump when it appears.
6. Do NOT stop at one skip link if the shell has a persistent sidebar or a heavy filter panel. Add targeted links for those too, but keep the total small; a list of eight skip links is its own obstacle.

## 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

- A sticky header must not sit on top of the content the skip link just jumped to — offset the scroll position for it.
- The main target must be present before the link is used, including on routes that render content asynchronously.
- Client-side navigation must not leave the skip link pointing at a target from the previous route.
- Search and complementary regions each need names when repeated, not just navigation.
- Wrapping decorative chrome in a landmark is worse than leaving it out — every extra region makes the landmark list noisier.
- A skip link visible only on hover is useless; it must respond to keyboard focus specifically.
- The link must sit above any fixed header in stacking order or it will be revealed behind it.

## 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

- [ ] The skip link is the first thing Tab reaches on every page and is plainly visible when focused.
- [ ] Activating it moves keyboard focus into the main content, not just the scroll position.
- [ ] Every route renders exactly one main landmark with a stable focusable target.
- [ ] Repeated navigation, search, and complementary regions have distinct accessible names.
- [ ] Revealing the skip link does not shift or reflow the page.
- [ ] The skip target is not obscured by sticky headers after the jump.
- [ ] 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.