# Login Attempt Alerts

## Objective

Tell the account owner when a sign-in looks like it needs their attention.

Notifications to the account owner about new-device sign-ins and bursts of failed attempts, with a direct path to lock the account down.

## 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. Alert on the events that actually matter: a successful sign-in from an unrecognised device, and a burst of failed attempts against the account.
2. Include the time, approximate location, browser, and platform, and state plainly what to do if it was not them.
3. Link to session revocation and password change, and require the user to authenticate before either — the alert link must never be a credential itself.
4. Deduplicate: one risk event produces one alert, and repeat alerts for the same device or the same failure burst are collapsed within a window.
5. Do NOT alert on every IP change. Mobile networks, VPNs, and corporate proxies rotate addresses constantly, and an alert users learn to ignore protects nobody.

## 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

- IP geolocation is frequently wrong by hundreds of miles. Say the country or region, never a street-level claim.
- A user with a rotating VPN will trip a naive new-device rule on every sign-in — key recognition to a stored device token, not to IP.
- Alerts about failed attempts must not confirm whether the password was close, or whether the account exists.
- Send the alert to a verified address; delivering a security alert to an unverified or recently changed email hands it to the attacker.
- If the attacker changed the email first, notify the previous address too.
- Let the user turn down new-device alerts, but never turn off the alert for a password or email change.

## 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

- [ ] New-device sign-ins and failed-attempt bursts generate alerts.
- [ ] Alerts include time, device, and approximate region without over-precise location.
- [ ] Repeat alerts for the same risk event are deduplicated within a window.
- [ ] Alert links require authentication before any account change.
- [ ] Alerts go only to verified addresses, and email changes notify the old address.
- [ ] Routine IP rotation does not trigger alerts.
- [ ] 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.