`tasks/prd-new-feature-for-angels-flowers.md`

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# Product Requirements Document: Dark Mode & Testing Infrastructure

## 1. Introduction/Overview

This PRD outlines the implementation of dark mode support and unit testing framework for Angel's Flowers, a premium Ecuadorian flower retailer serving East Los Angeles. The website will be enhanced to provide a better user experience across different lighting conditions while ensuring code quality through comprehensive testing.

**Project**: angels-flowers  
**Feature**: Dark Mode Support & Unit Testing Framework  
**Priority**: High  
**Target Users**: All website visitors and internal development team  
**Tech Stack**: Next.js 16 + React 19  

## 2. Goals

• Implement system-aware dark mode with manual toggle override
• Reduce eye strain for users browsing in low-light environments
• Optimize flower product images for dark mode viewing
• Establish comprehensive unit testing framework with 80%+ coverage
• Improve code reliability and maintainability
• Enable confident feature development and deployment
• Increase user engagement through improved user experience

## 3. User Stories

### US-001: Dark Mode Theme Detection
**Description**: As a user, I want the website to automatically detect my system's dark mode preference so that the site matches my device settings.
**Acceptance Criteria**:
- [ ] System automatically detects `prefers-color-scheme: dark` media query
- [ ] Website applies dark theme when system preference is dark
- [ ] Website applies light theme when system preference is light or not set
- [ ] Theme detection works on page load without flash of incorrect theme
- [ ] Typecheck passes
- [ ] Verify in browser using dev-browser skill

### US-002: Manual Dark Mode Toggle
**Description**: As a user, I want to manually toggle between light and dark mode so that I can override my system preference.
**Acceptance Criteria**:
- [ ] Toggle button is visible in website header/navigation
- [ ] Clicking toggle switches between light and dark themes
- [ ] Toggle state persists across page navigation
- [ ] Toggle state persists across browser sessions using localStorage
- [ ] Toggle shows current theme state (sun/moon icon or similar)
- [ ] Typecheck passes
- [ ] Verify in browser using dev-browser skill

### US-003: Homepage Dark Mode Styling
**Description**: As a user, I want the homepage to display properly in dark mode so that I can browse comfortably in low-light conditions.
**Acceptance Criteria**:
- [ ] Background color changes to dark theme (#1a1a1a or similar)
- [ ] Text color changes to light color (#ffffff or #f0f0f0)
- [ ] All buttons maintain proper contrast ratio (minimum 4.5:1)
- [ ] Hero section adapts to dark theme
- [ ] Navigation elements use appropriate dark theme colors
- [ ] Typecheck passes
- [ ] Verify in browser using dev-browser skill

### US-004: Product Catalog Dark Mode Styling
**Description**: As a user, I want the product catalog page to display properly in dark mode so that I can browse flower products without eye strain.
**Acceptance Criteria**:
- [ ] Product grid maintains proper spacing and contrast in dark mode
- [ ] Product cards have dark background with light text
- [ ] Price text remains clearly visible with proper contrast
- [ ] Filter/search controls adapt to dark theme
- [ ] Pagination controls use dark theme styling
- [ ] Typecheck passes
- [ ] Verify in browser using dev-browser skill

### US-005: Product Details Dark Mode Styling
**Description**: As a user, I want product detail pages to display properly in dark mode so that I can view flower details comfortably.
**Acceptance Criteria**:
- [ ] Product title and description text use light colors on dark background
- [ ] Add to cart button maintains brand colors with proper contrast
- [ ] Product specifications/details are clearly readable
- [ ] Related products section adapts to dark theme
- [ ] Breadcrumb navigation uses dark theme colors
- [ ] Typecheck passes
- [ ] Verify in browser using dev-browser skill

### US-006: Image Optimization for Dark Mode
**Description**: As a user, I want flower product images to be optimized for dark mode so that they don't appear too bright or harsh.
**Acceptance Criteria**:
- [ ] Product images have subtle brightness reduction (10-15%) in dark mode
- [ ] Image containers have appropriate dark backgrounds
- [ ] Image loading states use dark theme colors
- [ ] Hero images apply subtle overlay or filter in dark mode
- [ ] Image zoom functionality works properly in both themes
- [ ] Typecheck passes
- [ ] Verify in browser using dev-browser skill

### US-007: Jest Testing Framework Setup
**Description**: As a developer, I want Jest configured for the project so that I can write and run unit tests.
**Acceptance Criteria**:
- [ ] Jest is installed and configured in package.json
- [ ] Jest config file supports TypeScript files (.ts, .tsx)
- [ ] Jest config includes path mapping for Next.js aliases
- [ ] Test script added to package.json (`npm test`)
- [ ] Jest can run without errors on empty test suite
- [ ] Coverage reporting is configured and functional
- [ ] Typecheck passes

### US-008: React Testing Library Setup
**Description**: As a developer, I want React Testing Library configured so that I can test React components effectively.
**Acceptance Criteria**:
- [ ] @testing-library/react is installed and configured
- [ ] @testing-library/jest-dom is set up for custom matchers
- [ ] Test utilities are configured for Next.js environment
- [ ] Sample component test runs successfully
- [ ] Setup file is configured for global test setup
- [ ] Cleanup happens automatically after each test
- [ ] Typecheck passes

### US-009: Component Testing Suite
**Description**: As a developer, I want comprehensive tests for React components so that I can ensure UI reliability.
**Acceptance Criteria**:
- [ ] All customer-facing components have test files (*.test.tsx)
- [ ] Component rendering tests pass without errors
- [ ] Props handling is tested for each component
- [ ] User interaction tests cover click/form events
- [ ] Error boundary behavior is tested where applicable
- [ ] Test coverage for components is above 80%
- [ ] Typecheck passes

### US-010: Utility Functions Testing
**Description**: As a developer, I want tests for utility functions so that business logic is verified.
**Acceptance Criteria**:
- [ ] All utility functions have corresponding test files
- [ ] Edge cases are covered in utility tests
- [ ] Input validation is tested for each function
- [ ] Error handling scenarios are tested
- [ ] Pure function behavior is verified
- [ ] Test coverage for utilities is above 90%
- [ ] Typecheck passes

## 4. Functional Requirements

**FR-1**: Theme Management System
- Implement theme context provider using React Context API
- Support system preference detection via CSS media queries
- Provide manual override functionality with localStorage persistence
- Ensure theme state is accessible throughout component tree

**FR-2**: CSS Variables Architecture
- Define comprehensive CSS custom properties for colors
- Implement light and dark theme variable sets
- Ensure consistent color usage across all components
- Maintain proper contrast ratios for accessibility compliance

**FR-3**: Image Enhancement System
- Apply subtle filters to product images in dark mode
- Implement automatic brightness adjustment for hero images
- Ensure image quality is maintained across both themes
- Optimize loading performance for dual-theme images

**FR-4**: Testing Infrastructure
- Configure Jest with TypeScript support for Next.js 16
- Set up React Testing Library with custom render utilities
- Implement code coverage reporting with 80%+ target
- Create testing utilities for common scenarios

**FR-5**: Component Test Coverage
- Test all customer-facing page components
- Verify theme switching functionality
- Test user interactions and form submissions
- Validate error handling and edge cases

## 5. Non-Goals

• Admin/dashboard pages dark mode support (customer-facing only)
• Mobile app dark mode implementation
• Email template dark mode support
• Third-party widget/plugin dark mode integration
• Backend API testing (unit tests for frontend only)
• End-to-end testing implementation
• Performance testing framework
• Integration testing setup

## 6. Design Considerations

**Color Palette**:
- Dark theme primary background: #1a1a1a
- Dark theme secondary background: #2d2d2d
- Dark theme text: #ffffff / #f0f0f0
- Maintain brand colors for accents with adjusted opacity
- Ensure WCAG AA compliance (4.5:1 contrast ratio minimum)

**User Experience**:
- Smooth transitions between themes (0.3s ease-in-out)
- Persistent theme preference across sessions
- Clear visual indication of current theme state
- No flash of unstyled content during theme switching

**Image Handling**:
- Apply CSS filter: brightness(0.9) for dark mode images
- Use background overlays for hero sections
- Maintain image aspect ratios and quality
- Consider loading separate optimized images for dark mode

## 7. Technical Considerations

**Theme Implementation**:
- Use CSS-in-JS solution or CSS custom properties
- Implement theme provider at app root level
- Use Next.js theme detection to prevent hydration mismatch
- Consider using next-themes library for robust implementation

**Testing Architecture**:
- Jest 29+ with TypeScript support
- React Testing Library for component testing
- Mock Next.js router and image components
- Set up custom render function with theme providers

**Performance**:
- Minimize bundle size impact of theme switching
- Optimize CSS custom property updates
- Lazy load theme-specific assets
- Ensure smooth transitions without layout shift

**Browser Support**:
- Modern browsers with CSS custom properties support
- Graceful degradation for older browsers
- Test across Chrome, Firefox, Safari, Edge
- Ensure mobile browser compatibility

## 8. Success Metrics

**User Engagement**:
- Track dark mode adoption rate (target: 30% of users)
- Monitor session duration increase (target: 15% improvement)
- Measure page views per session (target: 10% increase)
- Track bounce rate reduction (target: 5% decrease)

**Code Quality**:
- Achieve 80%+ test coverage for components and utilities
- Zero failing tests in CI/CD pipeline
- Reduce bug reports related to UI inconsistencies
- Improve developer confidence scores in team surveys

**Performance**:
- Maintain current page load speeds (<3s on 3G)
- Theme switching completes within 300ms
- No increase in cumulative layout shift (CLS)
- Lighthouse accessibility score maintains 90+

**Business Impact**:
- Track conversion rate changes post-implementation
- Monitor customer support tickets for usability issues
- Measure development velocity improvement
- Track deployment confidence and rollback frequency

## 9. Open Questions

1. **Image Strategy**: Should we pre-generate dark mode optimized images or apply filters dynamically? Consider CDN bandwidth and processing costs.

2. **Testing Scope**: Should we include visual regression testing for dark mode, or is unit/integration testing sufficient for initial release?

3. **Theme Customization**: Do we need to support additional themes beyond light/dark, or should we focus on these two options initially?

4. **Legacy Browser Support**: What is our minimum browser support requirement for CSS custom properties and prefers-color-scheme?

5. **Marketing Integration**: How should we communicate the new dark mode feature to existing customers? Newsletter, banner, social media?

6. **Analytics Tracking**: What specific events should we track for dark mode usage to measure success beyond the defined metrics?

7. **Maintenance Strategy**: How often should we review and update test coverage? Who is responsible for maintaining test quality standards?