CSS Prompts

Create an interactive Sudoku game using HTML5, CSS3, and JavaScript. Build a clean, accessible game board with intuitive controls. Implement difficulty levels with appropriate puzzle generation algorithms. Add hint system with multiple levels of assistance. Include note-taking functionality for candidate numbers. Implement timer with pause and resume. Add error checking with optional immediate feedback. Include game saving and loading with multiple slots. Create statistics tracking for wins, times, and difficulty levels. Add printable puzzle generation. Implement keyboard controls and accessibility features.

Develop a feature-rich chess game using HTML5, CSS3, and JavaScript. Create a realistic chessboard with proper piece rendering. Implement standard chess rules with move validation. Add move highlighting and piece movement animation. Include game clock with multiple time control options. Implement notation recording with PGN export. Add game analysis with move evaluation. Include AI opponent with adjustable difficulty levels. Support online play with WebRTC or WebSocket. Add opening book and common patterns recognition. Implement tournament mode with brackets and scoring.

Build a comprehensive weather dashboard using HTML5, CSS3, JavaScript and the OpenWeatherMap API. Create a visually appealing interface showing current weather conditions with appropriate icons and background changes based on weather/time of day. Display a detailed 5-day forecast with expandable hourly breakdown for each day. Implement location search with autocomplete and history, supporting both city names and coordinates. Add geolocation support to automatically detect user's location. Include toggles for temperature units (°C/°F) and time formats. Display severe weather alerts with priority highlighting. Show detailed meteorological data including wind speed/direction, humidity, pressure, UV index, and air quality when available. Include sunrise/sunset times with visual indicators. Create a fully responsive layout using CSS Grid that adapts to all device sizes with appropriate information density.

Build a mindfulness meditation timer using HTML5, CSS3, and JavaScript. Create a serene, distraction-free interface with nature-inspired design. Implement customizable meditation sessions with preparation, meditation, and rest intervals. Add ambient sound options including nature sounds, binaural beats, and white noise. Include guided meditation with customizable voice prompts. Implement interval bells with volume control and sound selection. Add session history and statistics tracking. Create visual breathing guides with animations. Support offline usage as a PWA. Include dark mode and multiple themes. Add session scheduling with reminders.

Build a URL shortening service frontend using HTML5, CSS3, JavaScript and a backend API. Create a clean interface with prominent input field. Implement URL validation and sanitization. Add QR code generation for shortened URLs. Include click tracking and analytics dashboard. Support custom alias creation for URLs. Implement expiration date setting for links. Add password protection option for sensitive URLs. Include copy-to-clipboard functionality with confirmation. Create a responsive design for all devices. Add history of shortened URLs with search and filtering.

Create a web-based PDF viewer using HTML5, CSS3, JavaScript and PDF.js. Build a clean interface with intuitive navigation controls. Implement page navigation with thumbnails and outline view. Add text search with result highlighting. Include zoom and fit-to-width/height controls. Implement text selection and copying. Add annotation tools including highlights, notes, and drawing. Support document rotation and presentation mode. Include print functionality with options. Create a responsive design that works on all devices. Add document properties and metadata display.

Act as a Frontend Developer. You are tasked with creating the front-end for Xiaomi's self-service management system. Your responsibilities include:

- Designing a user-friendly interface using HTML5, CSS3, and JavaScript.
- Ensuring compatibility with various devices and screen sizes.
- Implementing interactive elements to enhance user engagement.
- Integrating with backend services to fetch and display data dynamically.
- Conducting thorough testing to ensure a seamless user experience.

Rules:
- Follow Xiaomi's design guidelines and branding.
- Ensure high performance and responsiveness.
- Maintain clean and well-documented code.

Variables:
- Bootstrap - The CSS framework to use
- apiEndpoint - The backend API endpoint
- #FF6700 - Primary theme color for the system

Example:
- Create a dashboard interface with user login functionality and data visualization features.

Act as a Frontend Developer. You are tasked with designing a sidebar dashboard interface that is both modern and user-friendly. Your responsibilities include:

- Creating a responsive layout using HTML5 and CSS3.
- Implementing interactive elements with JavaScript for dynamic content updates.
- Ensuring the sidebar is easily navigable and accessible, with collapsible sections for different functionalities.
- Using best practices for UX/UI design to enhance user experience.

Rules:
- Maintain clean and organized code.
- Ensure cross-browser compatibility.
- Optimize for mobile and desktop views.

Act as an Electron Frontend Developer. You are an expert in building desktop applications using Electron, focusing on frontend development.

Your task is to:
- Design and implement user interfaces that are responsive and user-friendly.
- Utilize HTML, CSS, and JavaScript to create dynamic and interactive components.
- Integrate Electron APIs to enhance application functionality.

Rules:
- Follow best practices for frontend architecture.
- Ensure cross-platform compatibility for Windows, macOS, and Linux.
- Optimize performance and reduce application latency.

Use variables such as projectName, React, and feature to customize the application development process.

# App Store Screenshots Gallery Generator

**Create a professional, production-ready screenshots gallery for an iOS/macOS/Android app that looks like it was designed by the top 1% of app developers.**

## Context

You are building a screenshots gallery page for an app. The project has screenshots in a folder (typically `screenshots/`, `fastlane/screenshots/`, or similar). The gallery should be a single HTML file that can be deployed to Netlify, Vercel, or any static host.

## Requirements

### 1. Design System Foundation

Create CSS custom properties (design tokens) for:

- **Colors**: Primary palette (50-900 shades), secondary/accent palette, neutral grays (50-900)
- **Surfaces**: Three surface levels (surface-1, surface-2, surface-3)
- **Typography**: Two-font stack (mono for UI elements, sans for body)
- **Spacing**: Consistent scale (4px base)
- **Borders**: Radius scale (sm, md, lg, xl, 2xl, 3xl)
- **Shadows**: Five elevation levels (sm, md, lg, xl, 2xl)
- **Transitions**: Three speeds (fast: 150ms, normal: 300ms, smooth: 400ms with cubic-bezier)

### 2. Layout Architecture

- **Container**: Max-width 1600px, centered, with responsive padding
- **Grid**: Masonry-style responsive grid using `grid-template-columns: repeat(auto-fill, minmax(340px, 1fr))`
- **Gap**: 2rem on desktop, 1.5rem tablet, 1rem mobile
- **Card aspect ratio**: Maintain consistent screenshot presentation

### 3. Header Section

- **App badge**: Small pill-shaped badge with icon and "IOS APPLICATION" or platform text
- **Title**: Large, bold app name with gradient text treatment
- **Subtitle**: One-line description mentioning key technologies and features
- **Background**: Subtle grid pattern overlay for depth
- **Padding**: Reduced vertical padding (3rem top, 2rem bottom) for compact feel

### 4. Screenshot Cards

Each card should have:

- **Container**: White/off-white background, rounded corners (2xl), subtle shadow
- **Image container**: Gradient background, centered screenshot with white border (8px)
- **Hover effects**:
  - Card lifts (-8px translateY) with enhanced shadow
  - Screenshot scales (1.04) with slight rotation (0.5deg)
  - Top border appears (gradient bar)
  - Radial glow overlay fades in
- **Metadata bar**:
  - Number badge (gradient background, 26px square)
  - Device name (uppercase, small font, mono font)
- **Title**: Bold, mono font, 1rem
- **Description**: One-line caption, smaller font, subtle color

### 5. User Journey Ordering

Order screenshots by how users experience the app:

1. **Login/Onboarding** - First screen users see
2. **Dashboard/Home** - Main landing after login
3. **Primary feature views** - Core app functionality
4. **Settings/Configuration** - Customization screens
5. **Permissions/Integrations** - HealthKit, notifications, etc.
6. **Advanced features** - Sync, sharing, cloud features
7. **Analytics/Reports** - Data visualization screens
8. **Archive/History** - Historical data views

### 6. Animations

- **Entrance**: Staggered fade-in with translateY (0.1s delays between cards)
- **Hover**: Smooth cubic-bezier easing (0.16, 1, 0.3, 1)
- **Scroll**: IntersectionObserver to trigger animations when cards enter viewport
- **Performance**: Use `will-change` for transform and opacity

### 7. Footer

- **Background**: Dark (neutral-900) with subtle gradient overlay
- **Border radius**: Top corners only (2xl)
- **Content**: Minimal metadata (device, date, status) with icons
- **Spacing**: Compact (2rem padding)

### 8. Responsive Breakpoints

- **Desktop** (>1280px): 4-5 columns
- **Tablet** (768-1280px): 2-3 columns
- **Mobile** (<768px): 1 column, reduced padding throughout

### 9. Technical Requirements

- **Single HTML file**: All CSS inline in `<style>` tag
- **External dependencies only**:
  - Pico.css (minimal CSS framework)
  - Font Awesome (icons)
  - Google Fonts (Inter + IBM Plex Mono)
  - Animate.css (optional, for additional animations)
- **No build step**: Must work as static HTML
- **Performance**: Optimized animations, no layout shift
- **Accessibility**: Semantic HTML, alt text on images

### 10. Polish Details

- **Subtle gradients**: Background radials for depth (not overwhelming)
- **Border treatment**: 1px solid with alpha transparency
- **Shadow layering**: Multiple shadow values for depth
- **Typography**: Tight letter-spacing on headings (-0.03em)
- **Color consistency**: Use design tokens everywhere, no hardcoded values
- **Image presentation**: White border around screenshots for device frame illusion

## Output Format

Generate a single `index.html` file with:

1. Complete HTML structure
2. Inline CSS with design tokens
3. JavaScript for scroll animations (IntersectionObserver)
4. All screenshot cards with proper metadata
5. Responsive design for all screen sizes

## Example Screenshot Card Structure

```html
<div class="screenshot-card">
    <div class="screenshot-img-container">
        <img src="screenshot-name.png" alt="Description" class="screenshot-img">
    </div>
    <div class="screenshot-info">
        <div class="screenshot-meta">
            <div class="screenshot-number">1</div>
            <div class="screenshot-device">iPhone 17 Pro Max</div>
        </div>
        <h3 class="screenshot-title">Screen Title</h3>
        <p class="screenshot-desc">One-line caption</p>
    </div>
</div>
```

## Key Differentiators from "AI-looking" Galleries

❌ **Avoid**:
- Excessive gradients and colors
- Large stat cards that waste space
- Verbose descriptions and feature lists
- Section dividers and category headers
- Overwhelming animations
- Inconsistent spacing
- Generic stock photography style

✅ **Emulate**:
- Apple App Store product pages
- Linear, Raycast, Superhuman marketing sites
- Minimalist, content-first design
- Subtle, refined interactions
- Consistent visual rhythm
- Typography-driven hierarchy
- White space as design element

## Deployment Notes

- Gallery should deploy to `project-root/screenshots-gallery/` or similar
- Include `.netlify` folder with `netlify.toml` for configuration
- All screenshots should be in the same folder as `index.html`
- No build process required - pure static HTML

---

**Usage**: Copy this prompt and provide it to an AI assistant along with:
1. The list of screenshot files in your project
2. Your app name and one-line description
3. The platform (iOS, macOS, Android, web)
4. Key technologies used (SwiftUI, React Native, Flutter, etc.)

The AI will generate a production-ready gallery that looks professionally designed.

You are a senior technical writer who specializes in making complex systems
understandable to non-engineers. You have a gift for analogy, narrative, and
turning architecture diagrams into stories.

I need you to analyze this project and write a comprehensive documentation
file called `FORME.md` that explains everything about this project in
plain language.

## Project Context
- **Project name:** name
- **What it does (one sentence):** [e.g., "A SaaS platform that lets restaurants manage their own online ordering without paying commission to aggregators"]
- **My role:** [e.g., "I'm the founder / product owner / designer — I don't write code but I make all product and architecture decisions"]
- **Tech stack (if you know it):** [e.g., "Next.js, Supabase, Tailwind" or "I'm not sure, figure it out from the code"]
- **Stage:** [MVP / v1 in production / scaling / legacy refactor]

## Codebase
[Upload files, provide path, or paste key files]

## Document Structure

Write the FORME.md with these sections, in this order:

### 1. The Big Picture (Project Overview)
Start with a 3-4 sentence executive summary anyone could understand.
Then provide:
- What problem this solves and for whom
- How users interact with it (the user journey in plain words)
- A "if this were a restaurant" (or similar) analogy for the entire system

### 2. Technical Architecture — The Blueprint
Explain how the system is designed and WHY those choices were made.
- Draw the architecture using a simple text diagram (boxes and arrows)
- Explain each major layer/service like you're giving a building tour:
  "This is the kitchen (API layer) — all the real work happens here.
  Orders come in from the front desk (frontend), get processed here,
  and results get stored in the filing cabinet (database)."
- For every architectural decision, answer: "Why this and not the obvious alternative?"
- Highlight any clever or unusual choices the developer made

### 3. Codebase Structure — The Filing System
Map out the project's file and folder organization.
- Show the folder tree (top 2-3 levels)
- For each major folder, explain:
  - What lives here (in plain words)
  - When would someone need to open this folder
  - How it relates to other folders
- Flag any non-obvious naming conventions
- Identify the "entry points" — the files where things start

### 4. Connections & Data Flow — How Things Talk to Each Other
Trace how data moves through the system.
- Pick 2-3 core user actions (e.g., "user signs up", "user places an order")
- For each action, walk through the FULL journey step by step:
  "When a user clicks 'Place Order', here's what happens behind the scenes:
  1. The button triggers a function in [file] — think of it as ringing a bell
  2. That bell sound travels to api_route — the kitchen hears the order
  3. The kitchen checks with [database] — do we have the ingredients?
  4. If yes, it sends back a confirmation — the waiter brings the receipt"
- Explain external service connections (payments, email, APIs) and what happens if they fail
- Describe the authentication flow (how does the app know who you are?)

### 5. Technology Choices — The Toolbox
For every significant technology/library/service used:
- What it is (one sentence, no jargon)
- What job it does in this project specifically
- Why it was chosen over alternatives (be specific: "We use Supabase instead of Firebase because...")
- Any limitations or trade-offs you should know about
- Cost implications (free tier? paid? usage-based?)

Format as a table:
| Technology | What It Does Here | Why This One | Watch Out For |
|-----------|------------------|-------------|---------------|

### 6. Environment & Configuration
Explain the setup without assuming technical knowledge:
- What environment variables exist and what each one controls (in plain language)
- How different environments work (development vs staging vs production)
- "If you need to change [X], you'd update [Y] — but be careful because [Z]"
- Any secrets/keys and which services they connect to (NOT the actual values)

### 7. Lessons Learned — The War Stories
This is the most valuable section. Document:

**Bugs & Fixes:**
- Major bugs encountered during development
- What caused them (explained simply)
- How they were fixed
- How to avoid similar issues in the future

**Pitfalls & Landmines:**
- Things that look simple but are secretly complicated
- "If you ever need to change [X], be careful because it also affects [Y] and [Z]"
- Known technical debt and why it exists

**Discoveries:**
- New technologies or techniques explored
- What worked well and what didn't
- "If I were starting over, I would..."

**Engineering Wisdom:**
- Best practices that emerged from this project
- Patterns that proved reliable
- How experienced engineers think about these problems

### 8. Quick Reference Card
A cheat sheet at the end:
- How to run the project locally (step by step, assume zero setup)
- Key URLs (production, staging, admin panels, dashboards)
- Who/where to go when something breaks
- Most commonly needed commands

## Writing Rules — NON-NEGOTIABLE

1. **No unexplained jargon.** Every technical term gets an immediate
   plain-language explanation or analogy on first use. You can use
   the technical term afterward, but the reader must understand it first.

2. **Use analogies aggressively.** Compare systems to restaurants,
   post offices, libraries, factories, orchestras — whatever makes
   the concept click. The analogy should be CONSISTENT within a section
   (don't switch from restaurant to hospital mid-explanation).

3. **Tell the story of WHY.** Don't just document what exists.
   Explain why decisions were made, what alternatives were considered,
   and what trade-offs were accepted. "We went with X because Y,
   even though it means we can't easily do Z later."

4. **Be engaging.** Use conversational tone, rhetorical questions,
   light humor where appropriate. This document should be something
   someone actually WANTS to read, not something they're forced to.
   If a section is boring, rewrite it until it isn't.

5. **Be honest about problems.** Flag technical debt, known issues,
   and "we did this because of time pressure" decisions. This document
   is more useful when it's truthful than when it's polished.

6. **Include "what could go wrong" for every major system.**
   Not to scare, but to prepare. "If the payment service goes down,
   here's what happens and here's what to do."

7. **Use progressive disclosure.** Start each section with the
   simple version, then go deeper. A reader should be able to stop
   at any point and still have a useful understanding.

8. **Format for scannability.** Use headers, bold key terms, short
   paragraphs, and bullet points for lists. But use prose (not bullets)
   for explanations and narratives.

## Example Tone

WRONG — dry and jargon-heavy:
"The application implements server-side rendering with incremental
static regeneration, utilizing Next.js App Router with React Server
Components for optimal TTFB."

RIGHT — clear and engaging:
"When someone visits our site, the server pre-builds the page before
sending it — like a restaurant that preps your meal before you arrive
instead of starting from scratch when you sit down. This is called
'server-side rendering' and it's why pages load fast. We use Next.js
App Router for this, which is like the kitchen's workflow system that
decides what gets prepped ahead and what gets cooked to order."

WRONG — listing without context:
"Dependencies: React 18, Next.js 14, Tailwind CSS, Supabase, Stripe"

RIGHT — explaining the team:
"Think of our tech stack as a crew, each member with a specialty:
- **React** is the set designer — it builds everything you see on screen
- **Next.js** is the stage manager — it orchestrates when and how things appear
- **Tailwind** is the costume department — it handles all the visual styling
- **Supabase** is the filing clerk — it stores and retrieves all our data
- **Stripe** is the cashier — it handles all money stuff securely"

## 🚀 URL Shortening Service — Full-Stack Application

### 📋 Project Overview
Build a production-ready, full-stack URL shortening service with a modern, accessible frontend and a robust RESTful backend API. The application must handle the complete lifecycle of shortened links: creation, redirection, tracking, management, and expiration. Prioritize performance, security, and an exceptional user experience across all devices.

---

### 🛠️ Tech Stack

**Frontend:**
- Semantic HTML5 with ARIA attributes for accessibility (WCAG 2.1 AA compliance)
- CSS3 with CSS Custom Properties (variables), Flexbox, and CSS Grid
- Vanilla JavaScript (ES2022+) using modular architecture (ES Modules)
- No heavy frameworks — keep the bundle lightweight and fast

**Backend API:**
- RESTful API design following OpenAPI 3.0 specification
- JSON request/response format with proper HTTP status codes
- CORS configuration for cross-origin requests
- Rate limiting per IP and per API key

**Libraries (CDN or bundled):**
- QR Code generation (e.g., `qrcode.js` or `qr-creator`)
- Charting library for analytics (e.g., Chart.js or lightweight alternative)
- Date picker for expiration (e.g., `flatpickr`)
- Toast notification system (custom-built, no dependency)

---

### 🎨 Frontend — UI/UX Requirements

**Layout & Design:**
- Clean, minimalist design with a hero section featuring a **large, prominent URL input field** centered on the page
- Implement a **dark/light mode toggle** with system preference detection (`prefers-color-scheme`) and `localStorage` persistence
- Use a consistent design system: typography scale, spacing tokens, color palette
- Smooth micro-animations and transitions (fade-ins, slide-ups, button ripples) for all interactive elements
- Skeleton loading states for async content (analytics, history table)

**Responsive Design:**
- Mobile-first approach with breakpoints at 480px, 768px, 1024px, and 1440px
- Touch-friendly tap targets (minimum 44×44px)
- Collapsible navigation menu on mobile (hamburger menu with animation)
- Fluid typography using `clamp()`

**Accessibility:**
- Full keyboard navigation support (tab order, focus trapping in modals)
- Screen reader announcements for dynamic content (`aria-live` regions)
- Visible focus indicators on all interactive elements
- Sufficient color contrast ratios (minimum 4.5:1 for text)
- Reduced motion support (`prefers-reduced-motion`)

---

### ⚙️ Core Features

#### 1. URL Shortening Engine
- Prominent input field with placeholder text and real-time validation feedback
- **URL validation**: Check for valid protocol (`http://`, `https://`), proper domain structure, and reject malformed URLs using both regex and the `URL` constructor API
- **URL sanitization**: Strip tracking parameters (UTM, fbclid, gclid), remove redundant slashes, normalize protocol and case
- Auto-prepend `https://` if no protocol is provided
- Display the shortened URL immediately after creation with a success animation
- **Bulk URL shortening**: Allow users to paste multiple URLs (one per line) and shorten them all at once

#### 2. Custom Alias Support
- Optional custom alias field (e.g., `short.ly/my-brand`)
- Real-time availability check as the user types (debounced API call, 300ms)
- Alias validation rules: alphanumeric, hyphens, underscores only; 3–30 characters; reserved word blacklist (e.g., `admin`, `api`, `login`, `static`)
- Clear error messaging if the alias is taken or invalid

#### 3. QR Code Generation
- Auto-generate a QR code for every shortened URL upon creation
- QR code modal/panel with options to:
  - Download as PNG (high resolution, 1024×1024)
  - Download as SVG (vector, scalable)
  - Customize foreground/background colors
  - Add a small logo overlay in the center (optional)
- Ensure QR codes encode the full shortened URL and are scannable at small sizes

#### 4. Click Tracking & Analytics Dashboard
- Track every redirect with the following data points:
  - Timestamp (UTC)
  - Country and city (via IP geolocation API)
  - Device type (mobile, tablet, desktop)
  - Operating system and browser (via User-Agent parsing)
  - Referrer URL
  - Unique vs. returning visitor (via cookie/fingerprint)
- **Analytics Dashboard** per link including:
  - Total clicks and unique clicks counters
  - Clicks over time line chart (filterable: last 24h, 7d, 30d, 90d, all time)
  - Geographic distribution map or bar chart (top 10 countries)
  - Device/OS/Browser breakdown (donut or pie charts)
  - Top referrers table
  - Click heatmap by day of week and hour of day
- Aggregate analytics overview on the main dashboard (total links, total clicks, most popular link)

#### 5. Link Expiration
- Optional expiration date/time picker when creating a link
- Support presets: 1 hour, 24 hours, 7 days, 30 days, custom date
- Display a countdown or "expires in X" badge on active links
- Automatically deactivate expired links and show a friendly "This link has expired" page on redirect attempts
- Allow users to extend or remove expiration on existing links

#### 6. Password Protection
- Optional password toggle when creating a link
- If enabled, show a password input gate page before redirecting to the target URL
- Hash passwords server-side using bcrypt or Argon2 (never store plaintext)
- Rate-limit password attempts (max 5 per minute per IP) with lockout messaging
- Visual indicator (lock icon 🔒) on password-protected links in the history view

#### 7. Copy-to-Clipboard
- One-click copy button next to every shortened URL
- Use the Clipboard API (`navigator.clipboard.writeText()`) with fallback to `document.execCommand('copy')`
- Visual confirmation: button icon changes to a checkmark ✅ with a "Copied!" tooltip/toast that auto-dismisses after 2 seconds
- Keyboard shortcut support (e.g., `Ctrl+Shift+C` to copy the most recently created link)

#### 8. URL History & Management
- Persistent history table/grid of all shortened URLs (stored in `localStorage` for guests, database for authenticated users)
- Each entry displays: original URL (truncated with tooltip), short URL, creation date, click count, status (active/expired/password-protected), and action buttons
- **Search**: Full-text search across original URLs, aliases, and tags
- **Filtering**: By status (active, expired, protected), date range, click count range, and tags
- **Sorting**: By creation date, click count, alphabetically (ascending/descending)
- **Pagination or infinite scroll** for large histories (25 items per page)
- **Bulk actions**: Select multiple links to delete, disable, or export as CSV/JSON
- **Tags/Labels**: Allow users to add custom tags to organize links (e.g., "marketing", "social", "campaign-q4")

---

### 🔒 Security Requirements
- Input sanitization on both client and server to prevent XSS attacks
- CSRF protection on all state-changing API endpoints
- Validate and sanitize redirect targets to prevent open redirect vulnerabilities (whitelist allowed protocols, block `javascript:`, `data:`, `file:` schemes)
- Implement Content Security Policy (CSP) headers
- Rate limiting: max 20 link creations per minute per IP; max 100 API requests per minute
- Secure HTTP headers: `X-Content-Type-Options`, `X-Frame-Options`, `Strict-Transport-Security`
- Never expose internal IDs; use nanoid or UUID for public link identifiers

---

### ⚡ Performance Requirements
- Target Lighthouse scores: Performance >90, Accessibility >95, Best Practices >95, SEO >90
- Lazy-load analytics charts and non-critical assets
- Debounce all search and validation inputs
- Use `IntersectionObserver` for scroll-based animations and lazy loading
- Minimize reflows and repaints; use CSS `transform` and `opacity` for animations
- Cache API responses where appropriate (e.g., analytics data with 60s TTL)
- Redirects should resolve in under 100ms server-side

---

### 🧪 Error Handling & Edge Cases
- Graceful error messages for: network failures, API timeouts, invalid URLs, duplicate aliases, server errors (500), rate limit exceeded (429)
- Offline detection: show a banner when the user loses connectivity and queue actions for retry
- Handle extremely long URLs (up to 2048 characters) without breaking the layout
- Handle Unicode/internationalized domain names (IDN) correctly
- Empty state illustrations for when the user has no links or no analytics data

---

### 📁 Deliverables
1. Complete, well-commented source code with a clear folder structure
2. `README.md` with setup instructions, API documentation, and feature list
3. API endpoint reference table (method, path, parameters, response format)
4. A `demo` mode with sample data pre-loaded for immediate preview
5. Responsive across Chrome, Firefox, Safari, and Edge (latest 2 versions)

---

> **Note:** Build this incrementally — start with the core shortening flow (input → validate → shorten → display → copy), then layer on QR codes, analytics, custom aliases, expiration, password protection, and the full history dashboard. Ensure each feature is fully functional and tested before moving to the next.

---
name: accessibility-color-contrast-auditor
description: Audits foreground/background color pairs for WCAG 2.x contrast (AA and AAA for normal and large text), reports ratios and pass/fail, and notes color-blindness risks. Use when checking UI palettes, design tokens, or asking "is this gray-on-white readable?". Includes a stdlib Python contrast checker with --self-test.
---

# Accessibility Color Contrast Auditor

You help designers and frontend engineers check whether text and UI colors meet WCAG 2.x contrast ratios. You compute relative luminance contrast for foreground/background pairs, map results to AA/AAA for normal and large text, and flag pairs that rely on hue alone for meaning.

## Files in this skill

- `scripts/contrast_check.py` - computes contrast ratios for hex pairs and prints a pass table (Python 3 standard library only)
- `references/wcag-contrast.md` - thresholds and what counts as large text
- `references/color-blindness-notes.md` - why hue-only status colors fail real users
- `templates/audit-table.md` - markdown table for design reviews
- `examples/palette.json` - sample token pairs

## Workflow

### 1. Collect pairs
Ask for hex colors (`#RGB`, `#RRGGBB`, or `#RRGGBBAA` with alpha ignored against an opaque background). Note which is text/icon (fg) and which is surface (bg).

### 2. Run the checker
```
python3 scripts/contrast_check.py --fg '#1a1a1a' --bg '#ffffff'
python3 scripts/contrast_check.py --palette examples/palette.json
python3 scripts/contrast_check.py --self-test
```

### 3. Interpret
- Normal text AA needs **4.5:1**; AAA needs **7:1**.
- Large text (18pt+ or 14pt+ bold) AA needs **3:1**; AAA needs **4.5:1**.
- Non-text UI components / graphical objects that convey meaning need **3:1** against adjacent colors (WCAG 2.1 SC 1.4.11).

### 4. Answer
For each pair: ratio (one decimal), AA/AAA normal, AA/AAA large, and a short fix suggestion (darken fg, lighten bg, or add weight/size). Mention color-blindness if status depends on red vs green alone.

## Rules

- Use the WCAG relative luminance formula; do not approximate with "eyeballing".
- Ignore marketing claims about "accessible mode" unless ratios are shown.
- If alpha blending is involved, ask for the effective flattened hex on the real background.
FILE:references/wcag-contrast.md
# WCAG contrast thresholds (WCAG 2.1 / 2.2)

| Content | AA | AAA |
| --- | --- | --- |
| Normal text | 4.5:1 | 7:1 |
| Large text | 3:1 | 4.5:1 |
| UI components & graphical objects (1.4.11) | 3:1 | — |

## Large text

Large text is at least **18 CSS pt** (typically 24px) regular, or **14 CSS pt** (typically 18.66px) bold.

## Relative luminance

For sRGB channel C_srgb in 0..1:

- if C_srgb <= 0.04045: C = C_srgb / 12.92
- else: C = ((C_srgb + 0.055) / 1.055) ^ 2.4

L = 0.2126 R + 0.7152 G + 0.0722 B

Contrast ratio = (L_lighter + 0.05) / (L_darker + 0.05)

## Notes

- Placeholder / disabled text is exempt from text contrast SCs but still benefits from clarity.
- Focus indicators need 3:1 against adjacent colors (2.4.11 / 2.4.13 depending on level).
FILE:references/color-blindness-notes.md
# Color blindness notes for palettes

Contrast ratio alone is not enough when meaning is carried only by hue.

## Common pitfalls

- **Red vs green status** without icon or label: deuteranomaly/protanomaly users may not tell them apart.
- **Chart series** distinguished only by color: add patterns, shapes, or direct labels.
- **Link color** same lightness as body text: underline or weight must remain when color is removed.
- **Error borders** that are only a pale red tint: ensure 3:1 against the background and include text/icon.

## Safer patterns

1. Pair color with text ("Error", "Success") or icon.
2. Use lightness differences, not only hue shifts.
3. Test a grayscale screenshot of the UI.
4. Avoid conveying required-field state with red alone.

## Deuteranopia-friendly tip

Prefer blue/orange or blue/brown pairs over red/green for categorical data when you must use two hues.
FILE:templates/audit-table.md
# Contrast audit

- **Product / screen**:
- **Date**:
- **Standard**: WCAG 2.2 AA (default) / AAA where noted

| Token / use | FG | BG | Ratio | AA normal | AAA normal | AA large | Notes / fix |
| --- | --- | --- | --- | --- | --- | --- | --- |
| body text | `#1a1a1a` | `#ffffff` | 16.1 | pass | pass | pass | |
| muted caption | `#9ca3af` | `#ffffff` | 2.5 | fail | fail | fail | Darken to ~`#6b7280` |

## Decisions

- [ ] Update tokens
- [ ] Accept large-text-only usage
- [ ] Add non-color cue
FILE:examples/palette.json
{
  "pairs": [
    {"name": "body_on_white", "fg": "#1a1a1a", "bg": "#ffffff"},
    {"name": "muted_on_white", "fg": "#9ca3af", "bg": "#ffffff"},
    {"name": "link_on_white", "fg": "#2563eb", "bg": "#ffffff"},
    {"name": "button_label", "fg": "#ffffff", "bg": "#2563eb"},
    {"name": "error_on_white", "fg": "#dc2626", "bg": "#ffffff"},
    {"name": "white_on_light_gray", "fg": "#ffffff", "bg": "#e5e7eb"}
  ]
}
FILE:scripts/contrast_check.py
#!/usr/bin/env python3
"""WCAG contrast ratio checker for hex fg/bg pairs.

Usage:
    python3 contrast_check.py --fg '#1a1a1a' --bg '#ffffff'
    python3 contrast_check.py --palette palette.json
    python3 contrast_check.py --self-test

Python 3 standard library only.
"""
from __future__ import annotations

import argparse
import json
import math
import sys
from typing import Dict, List, Tuple


def parse_hex(color: str) -> Tuple[float, float, float]:
    c = color.strip().lstrip("#")
    if len(c) == 3:
        c = "".join(ch * 2 for ch in c)
    if len(c) == 8:
        c = c[:6]  # ignore alpha
    if len(c) != 6:
        raise ValueError(f"Bad hex color: {color!r}")
    r = int(c[0:2], 16) / 255.0
    g = int(c[2:4], 16) / 255.0
    b = int(c[4:6], 16) / 255.0
    return r, g, b


def channel(c: float) -> float:
    if c <= 0.04045:
        return c / 12.92
    return ((c + 0.055) / 1.055) ** 2.4


def relative_luminance(rgb: Tuple[float, float, float]) -> float:
    r, g, b = rgb
    return 0.2126 * channel(r) + 0.7152 * channel(g) + 0.0722 * channel(b)


def contrast_ratio(fg: str, bg: str) -> float:
    l1 = relative_luminance(parse_hex(fg))
    l2 = relative_luminance(parse_hex(bg))
    lighter, darker = max(l1, l2), min(l1, l2)
    return (lighter + 0.05) / (darker + 0.05)


def evaluate(ratio: float) -> Dict[str, bool]:
    return {
        "aa_normal": ratio >= 4.5,
        "aaa_normal": ratio >= 7.0,
        "aa_large": ratio >= 3.0,
        "aaa_large": ratio >= 4.5,
        "ui_3_1": ratio >= 3.0,
    }


def format_row(name: str, fg: str, bg: str) -> str:
    ratio = contrast_ratio(fg, bg)
    ev = evaluate(ratio)
    flags = " ".join(
        f"{k}={'PASS' if v else 'FAIL'}"
        for k, v in ev.items()
        if k in ("aa_normal", "aaa_normal", "aa_large")
    )
    return f"{name}: {fg} on {bg} -> {ratio:.2f}:1  {flags}"


def self_test() -> int:
    cases = [
        ("black_white", contrast_ratio("#000000", "#ffffff"), 21.0),
        ("white_black", contrast_ratio("#ffffff", "#000000"), 21.0),
        ("body", contrast_ratio("#1a1a1a", "#ffffff") > 12.0, True),
        ("muted_fail_aa", evaluate(contrast_ratio("#9ca3af", "#ffffff"))["aa_normal"], False),
        ("link_aa", evaluate(contrast_ratio("#2563eb", "#ffffff"))["aa_normal"], True),
        ("same_color", abs(contrast_ratio("#ffffff", "#ffffff") - 1.0) < 1e-9, True),
        ("short_hex", abs(contrast_ratio("#000", "#fff") - 21.0) < 1e-9, True),
        ("parse3", parse_hex("#abc") == parse_hex("#aabbcc"), True),
        ("ui_pass", evaluate(3.0)["ui_3_1"], True),
        ("aaa_border", evaluate(7.0)["aaa_normal"], True),
        ("just_under_aa", evaluate(4.49)["aa_normal"], False),
    ]
    failed = 0
    for name, got, expected in cases:
        if isinstance(expected, float):
            ok = abs(float(got) - expected) < 0.05
        else:
            ok = got == expected
        failed += not ok
        print(f"{'PASS' if ok else 'FAIL'}  {name}: got={got!r} expected={expected!r}")
    print(f"\n{len(cases) - failed}/{len(cases)} passed")
    return 1 if failed else 0


def main(argv=None) -> int:
    p = argparse.ArgumentParser(description="Check WCAG contrast for fg/bg hex pairs.")
    p.add_argument("--fg")
    p.add_argument("--bg")
    p.add_argument("--palette", help="JSON file with {pairs:[{name,fg,bg}]}")
    p.add_argument("--json", action="store_true")
    p.add_argument("--self-test", action="store_true")
    a = p.parse_args(argv)
    if a.self_test:
        return self_test()
    rows = []
    if a.palette:
        data = json.load(open(a.palette, encoding="utf-8"))
        for pair in data.get("pairs", []):
            rows.append(pair)
    elif a.fg and a.bg:
        rows.append({"name": "pair", "fg": a.fg, "bg": a.bg})
    else:
        p.error("provide --fg and --bg, or --palette, or --self-test")
    out = []
    any_fail = False
    for row in rows:
        ratio = contrast_ratio(row["fg"], row["bg"])
        ev = evaluate(ratio)
        if not ev["aa_normal"]:
            any_fail = True
        item = {"name": row.get("name", "pair"), "fg": row["fg"], "bg": row["bg"], "ratio": round(ratio, 2), **ev}
        out.append(item)
        if not a.json:
            print(format_row(item["name"], item["fg"], item["bg"]))
    if a.json:
        print(json.dumps(out, indent=2))
    return 1 if any_fail else 0


if __name__ == "__main__":
    sys.exit(main())

# CSS taste of a design-minded frontend developer
- Use Tailwind CSS utility classes for component styling in application code. Confidence: 0.80
- Define colors, spacing, radii and fonts as design tokens in CSS custom properties. Confidence: 0.90
- Never hardcode hex colors inside components; always reference a token. Confidence: 0.85
- Build layouts with flexbox and grid, with gap for spacing instead of margins between siblings. Confidence: 0.90
- Design mobile first and add min-width breakpoints for larger screens. Confidence: 0.85
- Use container queries for components that live in containers of different widths. Confidence: 0.75
- Use rem for font sizes and spacing, and px only for hairline borders. Confidence: 0.80
- Use clamp() for fluid typography instead of many breakpoint overrides. Confidence: 0.75
- Keep specificity flat: single class selectors, no IDs, and no !important outside utilities. Confidence: 0.90
- Use cascade layers to order reset, base, components and utilities. Confidence: 0.70
- Support dark mode with prefers-color-scheme plus tokens, not duplicated component styles. Confidence: 0.85
- Respect prefers-reduced-motion and disable non-essential animation when it is set. Confidence: 0.90
- Never remove focus outlines; style them with :focus-visible instead. Confidence: 0.95
- Meet WCAG AA contrast for all text and interactive elements. Confidence: 0.90
- Animate only transform and opacity for smooth, cheap transitions. Confidence: 0.85
- Use logical properties such as margin-inline so layouts work in right-to-left languages. Confidence: 0.75
- Use the system font stack or self-hosted variable fonts with font-display: swap. Confidence: 0.80
- Set aspect-ratio and width and height on media to prevent layout shift. Confidence: 0.85
- Use native CSS nesting sparingly and never more than two levels deep. Confidence: 0.70
- Sort Tailwind classes automatically with the Prettier plugin. Confidence: 0.80
- Extract a component when the same long class list repeats, not an @apply class. Confidence: 0.75
- Make sure nothing scrolls horizontally at a 320px viewport width. Confidence: 0.85

# Design System taste of a pragmatic design systems engineer
- Define design tokens for color, spacing, typography, radius and motion in one source file, and generate CSS variables and platform outputs from it. Confidence: 0.90
- Name tokens by purpose, such as color-text-muted or space-inset-md, not by raw value like gray-500 or 16px. Confidence: 0.85
- Support light and dark themes by swapping semantic token values, never by overriding individual component styles. Confidence: 0.90
- Build components on accessible headless primitives such as Radix UI or React Aria instead of re-implementing focus and keyboard logic. Confidence: 0.85
- Meet WCAG 2.2 AA contrast for every token pairing and check it automatically when tokens change. Confidence: 0.90
- Keep the component API small: a few well-named variants and sizes beat dozens of boolean props. Confidence: 0.85
- Prefer composition with slots or children over configuration objects for complex components like dialogs and menus. Confidence: 0.80
- Forward refs and spread remaining props onto the root element so components work with forms, tooltips and tests. Confidence: 0.85
- Never hard-code colors, spacing or font sizes inside components; lint for raw values with Stylelint or an ESLint rule. Confidence: 0.85
- Document every component in Storybook with usage guidance, do and don't examples, and live controls. Confidence: 0.85
- Run visual regression tests with Chromatic or Playwright screenshots on every pull request. Confidence: 0.80
- Run automated accessibility checks with axe in component tests, and still test keyboard and screen reader flows by hand before release. Confidence: 0.85
- Publish the library as a versioned package with semantic versioning and a changelog generated by Changesets. Confidence: 0.90
- Treat a renamed prop or removed variant as a breaking change, and ship codemods for large migrations. Confidence: 0.75
- Deprecate before removing: mark the old API, log a development-only warning, and remove it in the next major version. Confidence: 0.85
- Ship ESM with tree-shakeable per-component entry points and mark CSS files as side effects correctly. Confidence: 0.80
- Respect prefers-reduced-motion and keep motion tokens short and purposeful. Confidence: 0.80
- Keep icons as a separate package of optimized SVG components with consistent size and stroke tokens. Confidence: 0.75
- Use logical CSS properties like margin-inline-start so components work in right-to-left layouts. Confidence: 0.75
- Keep Figma components and code components in sync by sharing token names and reviewing drift every release. Confidence: 0.70
- Measure adoption by scanning product repositories for library imports and one-off overrides. Confidence: 0.65
- Accept contributions through a short proposal template that covers the use case, API and accessibility before any code. Confidence: 0.70

# Tailwind CSS taste of a utility-first UI engineer
- Configure design tokens (colors, spacing, radii, fonts) once in the Tailwind theme and never hardcode hex values or arbitrary pixel sizes in markup. Confidence: 0.90
- Prefer theme-scale utilities over arbitrary values like `w-[437px]`; treat each arbitrary value as a missing token to add or a design to question. Confidence: 0.85
- Extract repeated utility groups into components (React, Vue, Svelte) rather than `@apply` classes in CSS files. Confidence: 0.85
- Reserve `@apply` for styling third-party markup or CMS content you cannot add classes to. Confidence: 0.75
- Use `prettier-plugin-tailwindcss` so class order is automatic and never argued about in review. Confidence: 0.95
- Build class names from complete static strings; never concatenate fragments like `text-color-500`, because the scanner cannot see them. Confidence: 0.95
- Use `clsx` plus `tailwind-merge` (or a `cn()` helper) so component props can override default classes without conflicts. Confidence: 0.85
- Model component variants with a typed variant helper such as `cva` instead of long ternary chains in `className`. Confidence: 0.80
- Write mobile-first: unprefixed utilities are the base and `sm:`, `md:`, `lg:` only add changes for wider screens. Confidence: 0.90
- Use container queries (`@container`, `@md:`) for reusable components whose layout depends on their slot, not the viewport. Confidence: 0.70
- Implement dark mode with CSS variables behind semantic color names like `bg-surface` and `text-muted`, rather than sprinkling `dark:` on every element. Confidence: 0.80
- Always style keyboard focus with `focus-visible:` rings and never remove outlines without a visible replacement. Confidence: 0.95
- Use the `typography` plugin's `prose` classes for long-form rendered Markdown instead of hand-styling every tag. Confidence: 0.80
- Keep `content`/source paths tight so builds stay fast and unused utilities never ship. Confidence: 0.85
- Use `group-*` and `peer-*` variants for parent and sibling state instead of adding JavaScript for hover or checked styles. Confidence: 0.75
- Respect `motion-reduce:` for animations and keep transitions short, around 150 to 200 ms. Confidence: 0.80
- Split a class list over several lines or into a variant object once it passes roughly 10 to 12 utilities. Confidence: 0.65
- Keep spacing on a consistent scale and use `gap-*` on flex and grid parents instead of margins on children. Confidence: 0.85
- Avoid `!important` modifiers except to override third-party styles you cannot change. Confidence: 0.80
- Document the token palette and the core components in Storybook or a styleguide page so designers and developers share one vocabulary. Confidence: 0.70