# Character Limits

## Objective

Show how much room is left before text gets rejected or cut off.

Live remaining-character feedback on limited fields, counting the same way the server does.

## 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. Find every field with a length limit — database column, API constraint, or downstream service — and surface that limit in the UI.
2. Count the same units the server counts. If the server counts Unicode characters, do not count UTF-16 code units in the browser; the two disagree on emoji and the user gets rejected for text that looked fine.
3. Show remaining count rather than used count once the field is near the limit, and change its emphasis at a threshold rather than colouring it from the start.
4. Decide whether to hard-block typing past the limit or allow overflow with a clear error. Hard blocking silently eats pasted text, so prefer allowing overflow and blocking submission.
5. Do NOT announce every keystroke to screen readers. Announce only when crossing the warning threshold and when going over.

## 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

- Pasting text over the limit must keep the text and show the overage, not truncate it without telling anyone.
- Line breaks must count consistently between client and server, including CRLF versus LF.
- Composed emoji and combining characters must count as the user perceives them, or the rule must be stated.
- Trailing whitespace trimmed by the server must be trimmed by the counter too.
- A field starting over the limit — imported or legacy data — must show the state clearly and still be editable.
- Colour alone must not carry the warning.

## 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 length-limited field shows its limit and remaining count.
- [ ] The client counts identically to the server, including emoji and line breaks.
- [ ] Pasted overflow is preserved and reported rather than silently truncated.
- [ ] Threshold and over-limit states are announced once, not on every keystroke.
- [ ] The over-limit state is conveyed by more than colour.
- [ ] Submission is blocked with a clear message when over the limit.
- [ ] 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.