Custom properties
Widely Available (since 2019-10-05)
Custom properties are CSS properties prefixed with -- that set values you can reuse with the var() function. For example, you can set a --key-color property to reuse as border-color: var(--key-color). Also known as CSS variables.
Browser support (view on caniuse.com)
- Chrome 49 Released on 2016-03-02
- Chrome Android 49 Released on 2016-03-09
- Edge 15 Released on 2017-04-05
- Firefox 31 Released on 2014-07-22
- Firefox for Android 31 Released on 2014-07-22
- Safari 9.1 Released on 2016-03-21
- Safari on iOS 9.3 Released on 2016-03-21
MDN documentation
Specifications
Web Platform Tests (WPT)
View the latest WPT test results for this featureSurveys
- State of CSS 2026 > usage > favorite new features
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- State of CSS 2026 > colors > colors pain points
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