Responsive Design Mobile

Responsive Design is the practice of building web interfaces that automatically adapt to different screen sizes, from tiny phones to large monitors. It uses CSS media queries, flexible grids (Flexbox/CSS Grid), and fluid typography to adjust layouts based on viewport width. The same HTML serves all devices; CSS determines how it displays. Modern responsive design combines mobile-first thinking (start small, add features), semantic HTML, and progressive enhancement (core functionality works without JavaScript, enhancements layer on top).