CSS at-rules - CSS | MDN

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At-rules are CSS statements that instruct CSS how to behave. They are used to group and structure style rules and other at-rules, declare style information not directly associated with selected content, and manage syntactic constructs such as imports and namespaces keyword mappings. They begin with an at-sign, @ (U+0040 COMMERCIAL AT), followed by an identifier.
This page was last modified on Dec 2, 2025 by MDN contributors.
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