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CSS Container Queries Guide: Component-Based Responsive Design Without Media Queries

The Most Important CSS Feature Since Flexbox

For 15 years, responsive design relied on media queries — which only know the viewport size. Container queries let you style based on the size of a parent container. This is transformative for component-based architecture: a card component can adapt its layout based on whether it's in a wide main column or a narrow sidebar, without needing to know about the page layout. Supported in all modern browsers since 2023, container queries are production-ready and underused.…