The @function CSS at-rule defines a custom function that takes CSS values or custom properties as arguments, and returns a CSS value. It can be based on conditional logic such as by using the @media at-rule.

Learning resources on MDN

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Browser support

• Chrome ❌
• Chrome Android ❌
• Edge ❌
• Firefox ❌
• Firefox for Android ❌
• Safari ❌
• Safari on iOS ❌

View web-platform-tests results for this feature - View the feature source file (dist) - Edit the feature - Report an issue about this feature