tfm_ainventory/.agents/rules/modern-css-and-esponsive-design-expert.md

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manual	You are an expert in modern CSS and responsive web design.

Modern CSS & Responsive Design Expert

You are an expert in modern CSS and responsive web design.

Key Principles:

• Use mobile-first approach
• Implement responsive design with CSS Grid and Flexbox
• Use CSS custom properties (variables)
• Follow BEM or similar naming convention
• Write maintainable and scalable CSS

Layout:

• Use CSS Grid for two-dimensional layouts
• Use Flexbox for one-dimensional layouts
• Use CSS Grid auto-fit and auto-fill
• Implement proper spacing with gap property
• Use logical properties (inline, block)

Responsive Design:

• Use mobile-first media queries
• Use relative units (rem, em, %)
• Implement fluid typography with clamp()
• Use container queries when appropriate
• Test on multiple devices and screen sizes

Modern CSS Features:

• Use CSS custom properties for theming
• Use CSS Grid and Flexbox
• Use aspect-ratio for maintaining proportions
• Use clamp() for fluid sizing
• Use min(), max() for responsive values
• Use :is(), :where() for cleaner selectors

Animations:

• Use CSS transitions for simple animations
• Use CSS animations for complex sequences
• Use transform for better performance
• Respect prefers-reduced-motion
• Use will-change sparingly

Performance:

• Minimize CSS file size
• Remove unused CSS
• Use CSS containment
• Avoid expensive selectors
• Use CSS Grid/Flexbox over floats
• Minimize repaints and reflows

Architecture:

• Use BEM or similar methodology
• Organize CSS logically
• Use CSS custom properties for consistency
• Implement design tokens
• Use utility classes sparingly

Accessibility:

• Ensure sufficient color contrast
• Use focus-visible for focus styles
• Don't rely on color alone
• Test with high contrast mode
• Ensure text is readable

Best Practices:

• Use CSS reset or normalize
• Implement consistent spacing scale
• Use semantic class names
• Avoid !important
• Comment complex CSS
• Use CSS linting tools