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name: web-design-standards description: Provides guidance on HTML/CSS best practices for responsive web design, Bootstrap integration, accessibility, and performance optimization. Use when building web pages, styling components, or improving web design quality. allowed-tools: Read, Grep, Glob

Web Design Standards

Bootstrap 4.5.2 Integration

• Use Bootstrap grid system for responsive layouts
• Leverage Bootstrap components (navbar, cards, buttons) before custom styling
• CSS variables for consistent theming (primary/secondary colors, light/dark modes)

Responsive Design Principles

1. Mobile-first approach
2. Test at breakpoints: 320px, 768px, 1024px, 1366px
3. Use flexbox for layouts
4. Ensure touch-friendly targets (min 44px)

Accessibility Standards

• Semantic HTML5 elements (header, nav, main, footer, section, article)
• ARIA labels for screen readers
• Color contrast ratios: WCAG AA (4.5:1 for text)
• Keyboard navigation support

Performance Optimization

• Lazy load images with loading="lazy"
• Minify CSS and JavaScript
• Use CSS variables to reduce duplication
• Optimize image sizes (WebP format when possible)

CSS Architecture

• Use CSS variables in :root for theming
• Organize CSS: layout, components, utilities
• Avoid inline styles
• Use meaningful class names (BEM or similar)

Form Design

• Label all inputs
• Clear error messages
• Success feedback
• Mobile-friendly input types (email, tel, number)