modern-css

What it does

This skill equips AI agents with the ability to generate, debug, and optimize code using contemporary CSS standards. It enables the creation of responsive layouts, advanced animations, and maintainable stylesheets without relying on legacy syntax or external preprocessors.

When to use it

• Responsive Design: Building interfaces that adapt fluidly across mobile, tablet, and desktop viewports.
• Modern Syntax Adoption: Implementing features like CSS Grid, Flexbox, custom properties (variables), and logical properties.
• Performance Optimization: Reducing bundle size and improving render times by leveraging native browser capabilities instead of heavy libraries.
• Accessibility Enforcement: Ensuring styles meet WCAG guidelines through proper contrast ratios and focus management.

Key capabilities

• Generates valid CSS3 and CSS4 syntax compliant with current browser support.
• Implements complex layouts using Grid and Flexbox without JavaScript dependencies.
• Manages theming via CSS custom properties (variables) for dynamic styling.
• Applies modern selectors, pseudo-elements, and media queries for precise targeting.

Example prompts

• "Create a responsive navigation bar using only modern CSS that collapses on mobile devices."
• "Write a CSS snippet to animate a button hover effect using @keyframes and logical properties."
• "Optimize this stylesheet by converting hardcoded values into CSS custom properties."

Tips & gotchas

Ensure the target environment supports modern browsers, as some advanced features may require polyfills for older versions. Always test generated styles in real devices to verify rendering consistency across different operating systems.