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Container queries enable us to style an element depending on the size of its parent — a crucial difference from media queries, which only query the viewport. This has long been a problem for responsive design, as often we want a component to adapt to its context.
Think of a card which might be shown in a wide content area or a narrow sidebar. We’d probably want to show something more akin to the card’s mobile layout in the sidebar, while perhaps showing style when there is sufficient horizontal space. But media queries aren’t aware of the component’s context. For this reason, container queries have been on many a developer’s wish list for some time.
Container Queries