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HTML Guide

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Find out what web pages on your sites are affected by HTML issues.

CSS: Unrecognized at-rule “@container”

The @container CSS at-rule is a conditional group rule that applies styles to a containment context. The @container at-rule is a recent addition to CSS which isn’t officially a standard rule instead, although widely supported by major browsers.

Check the linked guides to learn more about browser compatibility for this rule.

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Related W3C validator issues