# Feature Specification: 404 Page

**Feature**: `026-404-page`
**Created**: 2026-03-06
**Status**: Draft
**Source**: Migrated from spec/userstories.md

## User Scenarios & Testing

### User Story 1 - See a helpful error page for unknown URLs (Priority: P1)

As a user who navigates to a non-existent URL, I want to see a helpful error page so that I can find my way back instead of seeing a blank screen.

**Why this priority**: Without this, users see a blank page on invalid routes. Basic UX hygiene.

**Independent Test**: Navigate to any non-existent path (e.g. `/does-not-exist`) and verify the error page renders with a way back.

**Acceptance Scenarios**:

1. **Given** a user navigates to a URL that does not match any defined route, **When** the page loads, **Then** a "Page not found" message is displayed.
2. **Given** the 404 page is displayed, **When** the user looks for navigation, **Then** a link back to the home page is visible and functional.
3. **Given** the 404 page is displayed, **When** its appearance is evaluated, **Then** it follows the project design system (Electric Dusk + Sora).

### Edge Cases

- What happens when the URL contains special characters or very long paths? The catch-all route should still match and display the 404 page.
- What happens when JavaScript is disabled? [NEEDS EXPANSION — SPA limitation]

## Requirements

### Functional Requirements

- **FR-001**: The Vue Router MUST include a catch-all route that matches any undefined path.
- **FR-002**: The catch-all route MUST render a dedicated 404 component with a "Page not found" message.
- **FR-003**: The 404 page MUST include a link back to the home page.
- **FR-004**: The 404 page MUST follow the design system defined in `.specify/memory/design-system.md`.

## Success Criteria

### Measurable Outcomes

- **SC-001**: Navigating to any undefined route displays the 404 page instead of a blank screen.
- **SC-002**: The home page link on the 404 page navigates back to `/` successfully.
- **SC-003**: The 404 page passes WCAG AA contrast requirements.

**Dependencies:** None (requires frontend scaffold from T-1/T-4 to be practically implementable)

**Notes:** Identified during US-1 post-review. Navigating to an unknown path currently shows a blank page because the Vue Router has no catch-all route.