Web Design Builder

This skill creates professional HTML5/JavaScript web designs from specifications, with automatic accessibility and functionality verification using Playwright MCP.

When to Use This Skill

Activate this skill when the user requests:

Create a web design from a specification or description
Build a landing page, website, or web application
Create a design mockup or prototype
Refactor or improve existing HTML/CSS/JavaScript code
Build responsive web interfaces
Create component libraries or design systems
Generate accessible web designs with WCAG compliance

Core Workflow

Phase 1: Requirements Gathering

When a user requests a web design, start by understanding their needs:

Clarify the Design Scope
- What type of design? (landing page, dashboard, form, etc.)
- Target audience and use case
- Required features and functionality
- Content and copy (provided or placeholder?)
- Brand colors, fonts, or design system
- Responsive requirements (mobile-first?)
Technical Preferences
- Framework preference:
  - Vanilla HTML/CSS/JS (simple, no dependencies)
  - Tailwind CSS (utility-first, recommended for rapid development)
  - React (component-based, for complex interactions)
  - Vue (progressive framework)
  - Alpine.js (lightweight reactivity)
- Browser support requirements
- Accessibility requirements (WCAG level)
- Performance constraints
Check Playwright MCP Availability

IMPORTANT: Before starting the design process, check if Playwright MCP is available:
```
// Check if mcp__playwright tools are available
// Look for tools like: mcp__playwright__navigate, mcp__playwright__screenshot, etc.
```
If Playwright MCP is NOT available:
- Inform the user: "Playwright MCP is not installed. Design verification will be skipped."
- Provide installation instructions (see MCP Setup section below)
- Continue with design generation but skip verification phase
- Mark this clearly in the output
If Playwright MCP IS available:
- Inform the user: "Playwright MCP detected. Design will be automatically verified."
- Include verification in the workflow

Phase 2: Design Generation

Step 1: Create Design Mockup

Generate a complete HTML/CSS/JS mockup including:

HTML Structure:

Semantic HTML5 elements
Proper heading hierarchy (h1 → h6)
ARIA landmarks (header, nav, main, aside, footer)
Accessible form labels and inputs
Alt text for images
Unique page title

CSS Styling:

Responsive design (mobile-first)
CSS Grid or Flexbox for layouts
Custom properties (CSS variables) for theming
Smooth transitions and animations
Print styles (if applicable)
Dark mode support (optional)

JavaScript Functionality:

Progressive enhancement
Accessible interactions (keyboard support)
Form validation
Dynamic content loading
Event handling
Error handling

Accessibility Features:

WCAG 2.1 Level AA compliance minimum
Keyboard navigation support
Focus indicators
Screen reader friendly
Color contrast compliance (4.5:1 minimum)
Skip links
ARIA attributes where needed

Example Output Structure:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Page Title</title>
  <style>
    /* Modern CSS with custom properties */
    :root {
      --primary-color: #0066cc;
      --text-color: #1a1a1a;
      --bg-color: #ffffff;
      --spacing: 1rem;
    }

    /* Reset and base styles */
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
      line-height: 1.6;
      color: var(--text-color);
      background: var(--bg-color);
    }

    /* Responsive layout */
    @media (max-width: 768px) {
      /* Mobile styles */
    }
  </style>
</head>
<body>
  <!-- Accessible skip link -->
  <a href="#main-content" class="skip-link">Skip to main content</a>

  <!-- Semantic structure -->
  <header role="banner">
    <nav aria-label="Main navigation">
      <!-- Navigation -->
    </nav>
  </header>

  <main id="main-content" role="main">
    <!-- Main content -->
  </main>

  <footer role="contentinfo">
    <!-- Footer -->
  </footer>

  <script>
    // Progressive enhancement JavaScript
    (function() {
      'use strict';

      // Feature detection
      if (!('querySelector' in document)) return;

      // Your JavaScript here
    })();
  </script>
</body>
</html>

Step 2: Save Design to File

Save the generated design to a file:

// Recommended file structure
project-name/
  index.html         // Main HTML file
  styles.css         // Separate CSS (if needed)
  script.js          // Separate JS (if needed)
  assets/
    images/          // Image assets
    fonts/           // Custom fonts

Use the Write tool to create the file:

Save to user's current directory or ask for preferred location
Use descriptive filename (e.g., landing-page.html, dashboard.html)
Create single-file HTML for mockups (CSS/JS inline)
Create separate files for production builds

Phase 3: Design Verification (ONLY if Playwright MCP is available)

IMPORTANT: Only execute this phase if Playwright MCP was detected in Phase 1.

Step 1: Launch Browser and Load Design

Use Playwright MCP to open the design:

// Navigate to the local HTML file
await mcp__playwright__navigate({
  url: 'file:///path/to/design.html'
});

Step 2: Accessibility Testing

Run comprehensive accessibility checks:

Automated Accessibility Scan
- Check for WCAG violations
- Verify color contrast ratios
- Check heading hierarchy
- Verify ARIA attributes
- Check form labels
- Verify alt text on images
Keyboard Navigation Test
- Tab through all interactive elements
- Verify focus indicators are visible
- Check tab order is logical
- Test Escape key behavior (modals, dropdowns)
- Verify no keyboard traps
Screen Reader Compatibility
- Check ARIA landmarks
- Verify semantic HTML usage
- Check dynamic content announcements
- Verify form error messages

Step 3: Visual Testing

Capture screenshots and verify layout:

// Take full-page screenshot
await mcp__playwright__screenshot({
  fullPage: true,
  path: 'design-screenshot.png'
});

// Test responsive breakpoints
const breakpoints = [
  { width: 375, height: 667, name: 'mobile' },
  { width: 768, height: 1024, name: 'tablet' },
  { width: 1440, height: 900, name: 'desktop' }
];

for (const bp of breakpoints) {
  await mcp__playwright__setViewportSize({
    width: bp.width,
    height: bp.height
  });

  await mcp__playwright__screenshot({
    path: `design-${bp.name}.png`
  });
}

Step 4: Functionality Testing

Test interactive elements:

Form Validation
- Test required fields
- Test input validation
- Test error messages
- Test success states
Interactive Components
- Test buttons and links
- Test modals and dialogs
- Test dropdowns and menus
- Test tabs and accordions
- Test carousels and sliders
JavaScript Functionality
- Verify event handlers work
- Test dynamic content loading
- Check console for errors
- Verify progressive enhancement

Step 5: Performance Check

Evaluate performance metrics:

Load Time
- Measure page load time
- Check resource loading
- Identify bottlenecks
Resource Optimization
- Check CSS file size
- Check JavaScript file size
- Verify image optimization
- Check for unused CSS/JS

Phase 4: Verification Report

Generate a comprehensive report:

# Design Verification Report

## Overview
- **Design Type**: [Landing Page / Dashboard / etc.]
- **Framework**: [Vanilla / Tailwind / React / etc.]
- **Verification Date**: [Date]
- **Playwright MCP**: [Available / Not Available]

## Accessibility Compliance

### WCAG 2.1 Level AA
✅ **PASSED**: Color contrast (4.5:1 minimum)
✅ **PASSED**: Keyboard navigation
✅ **PASSED**: Semantic HTML structure
⚠️  **WARNING**: Missing alt text on 2 images
❌ **FAILED**: Form missing associated labels

### Issues Found
1. **HIGH**: Form input #email missing label
   - Location: Line 45
   - Fix: Add `<label for="email">Email</label>`

2. **MEDIUM**: Image missing alt text
   - Location: Line 78
   - Fix: Add `alt="Description of image"`

## Visual Testing

### Responsive Breakpoints
✅ **Mobile (375px)**: Layout renders correctly
✅ **Tablet (768px)**: Layout renders correctly
✅ **Desktop (1440px)**: Layout renders correctly

### Screenshots
- [x] Full page screenshot saved
- [x] Mobile screenshot saved
- [x] Tablet screenshot saved
- [x] Desktop screenshot saved

## Functionality Testing

### Interactive Elements
✅ Navigation menu works
✅ Form submission works
✅ Modal opens and closes
⚠️  Focus not returned to trigger after modal close

### JavaScript
✅ No console errors
✅ Event handlers working
✅ Progressive enhancement implemented

## Performance

### Metrics
- **Page Load Time**: 1.2s
- **Total File Size**: 45KB
- **CSS Size**: 12KB
- **JavaScript Size**: 8KB

### Optimization Opportunities
- Consider minifying CSS (potential 30% reduction)
- Lazy load images below the fold
- Consider code splitting for JavaScript

## Recommendations

### High Priority
1. Fix form label associations
2. Add missing alt text to images
3. Implement focus management for modal

### Medium Priority
1. Minify CSS and JavaScript for production
2. Add loading states for dynamic content
3. Implement error boundaries for JavaScript

### Low Priority
1. Add dark mode support
2. Enhance animations with reduced motion support
3. Add print styles

## Next Steps

1. Review and fix high-priority issues
2. Re-run verification after fixes
3. Test with actual screen readers
4. Conduct user testing
5. Deploy to staging environment

Phase 5: Iteration and Refinement

Based on verification results:

Fix Critical Issues
- Address all accessibility violations
- Fix broken functionality
- Resolve layout issues
Apply Improvements
- Implement recommended optimizations
- Enhance visual design based on feedback
- Refine interactions and animations
Re-verify
- Run verification again after fixes
- Ensure all issues are resolved
- Generate updated report
Deliver Final Design
- Provide clean, production-ready code
- Include documentation
- Provide deployment instructions
- Share verification report

Design Patterns & Best Practices

Responsive Design

Mobile-First Approach:

/* Base styles for mobile */
.container {
  padding: 1rem;
}

/* Tablet and up */
@media (min-width: 768px) {
  .container {
    padding: 2rem;
    max-width: 960px;
    margin: 0 auto;
  }
}

/* Desktop and up */
@media (min-width: 1024px) {
  .container {
    padding: 3rem;
    max-width: 1200px;
  }
}

Accessible Forms

<form class="contact-form">
  <div class="form-field">
    <label for="name">
      Name <span aria-label="required">*</span>
    </label>
    <input
      type="text"
      id="name"
      name="name"
      required
      aria-required="true"
      aria-describedby="name-error"
    />
    <span id="name-error" class="error" role="alert" hidden>
      Please enter your name
    </span>
  </div>
</form>

Interactive Components

Accessible Modal:

function openModal(modalId) {
  const modal = document.getElementById(modalId);
  const lastFocused = document.activeElement;

  modal.hidden = false;
  modal.setAttribute('aria-modal', 'true');

  // Focus first focusable element
  const firstFocusable = modal.querySelector('button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])');
  firstFocusable?.focus();

  // Store last focused for return
  modal.dataset.lastFocused = lastFocused;

  // Trap focus
  trapFocus(modal);
}

function closeModal(modalId) {
  const modal = document.getElementById(modalId);
  modal.hidden = true;

  // Return focus
  const lastFocused = document.querySelector(`[data-last-focused="${modal.id}"]`);
  lastFocused?.focus();
}

Framework-Specific Guidelines

Tailwind CSS

Pros:

Rapid development
Consistent design system
Built-in responsive utilities
Excellent for prototyping

Setup:

<script src="https://cdn.tailwindcss.com"></script>
<script>
  tailwind.config = {
    theme: {
      extend: {
        colors: {
          primary: '#0066cc',
        }
      }
    }
  }
</script>

Example:

<div class="container mx-auto px-4">
  <h1 class="text-4xl font-bold text-gray-900 mb-4">
    Welcome
  </h1>
  <button class="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-4 rounded">
    Click Me
  </button>
</div>

React

Pros:

Component reusability
Virtual DOM performance
Large ecosystem
Great for SPAs

Example:

function DesignComponent() {
  const [isOpen, setIsOpen] = React.useState(false);

  return (
    <div className="container">
      <button
        onClick={() => setIsOpen(!isOpen)}
        aria-expanded={isOpen}
      >
        Toggle
      </button>
      {isOpen && (
        <div className="content">
          Content here
        </div>
      )}
    </div>
  );
}

Alpine.js

Pros:

Lightweight (15KB)
Declarative syntax
No build step needed
Good for progressive enhancement

Example:

<div x-data="{ open: false }">
  <button @click="open = !open" :aria-expanded="open">
    Toggle
  </button>
  <div x-show="open" x-transition>
    Content here
  </div>
</div>

MCP Setup Instructions

If Playwright MCP is not available, provide these instructions to the user:

Installing Playwright MCP

Option 1: Via NPM (Recommended)

# Install Playwright MCP server
npm install -g @playwright/mcp-server

# Configure in Claude Code
claude code mcp add playwright

Option 2: Manual Setup

Create MCP configuration file:

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": ["@playwright/mcp-server"],
      "env": {}
    }
  }
}

Restart Claude Code

Verification: After installation, verify Playwright MCP is working:

# Check MCP servers
claude code mcp list

You should see playwright in the list of available MCP servers.

Communication Style

When working with users:

Clarify Requirements First
- Ask about design goals and constraints
- Understand technical requirements
- Confirm framework preferences
Provide Context
- Explain design decisions
- Justify framework choices
- Describe accessibility considerations
Show Progress
- Inform when generating design
- Update during verification (if MCP available)
- Share findings incrementally
Be Actionable
- Provide specific fixes for issues
- Include code examples
- Offer alternatives when appropriate
Handle MCP Unavailability Gracefully
- Clearly state when verification is skipped
- Provide manual testing guidance
- Offer installation instructions

Deliverables

At the end of the design process, provide:

Complete Design Files
- HTML, CSS, JavaScript files
- Assets (if any)
- README with setup instructions
Verification Report (if MCP available)
- Accessibility compliance results
- Visual testing screenshots
- Functionality test results
- Performance metrics
- Prioritized recommendations
Documentation
- Component usage guide
- Customization instructions
- Browser support information
- Deployment guidelines
Next Steps
- Suggested improvements
- Testing recommendations
- Production checklist

Example Workflow

User Request:

"Create a landing page for a SaaS product with a hero section, features, pricing, and contact form."

Your Response:

Clarify Requirements:
- "I'll create a modern SaaS landing page. A few questions:
  - Do you have brand colors or should I use a professional default palette?
  - Framework preference? I recommend Tailwind CSS for rapid development.
  - Any specific features to highlight?
  - Contact form fields needed?"
Check Playwright MCP:
- "Checking for Playwright MCP... Not detected. Design verification will be skipped. Would you like installation instructions?"
Generate Design:
- Create complete HTML/CSS/JS file
- Include hero, features, pricing, contact form
- Make it responsive and accessible
- Save to saas-landing-page.html
Manual Verification Guide (since MCP not available):
- Provide checklist for manual testing
- Share accessibility testing tools
- Suggest browser testing approach
Deliver:
- Share complete design file
- Provide customization guide
- Offer iteration if needed

Remember: The goal is to create beautiful, accessible, functional web designs that work for all users, with automatic verification when possible!