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Aponyfill that provides client-side support forCSS custom properties (aka "CSS variables") in legacy and modern browsers.

• Documentation & Demos

• Client-side transformation of CSS custom properties to static values
• Live updates of runtime values in both modern and legacy browsers
• Transforms<link>,<style>, and@import CSS
• Transforms relativeurl() paths to absolute URLs
• Supports chained and nestedvar() functions
• Supportsvar() function fallback values
• Supports web components / shadow DOM CSS
• Watch mode auto-updates on<link> and<style> changes
• UMD and ES6 module available
• TypeScript definitions included
• Lightweight (6k min+gzip) and dependency-free

Limitations

• Custom property declaration support is limited to:root and:host rulesets
• The use ofvar() is limited to property values (perW3C specification)
• CSS changes made usingCSSOM APIs are not supported (see#19,#23,#77,#154).

Browser Support

Chrome 19+
Edge 12+
Firefox 6+
IE 9+
Safari 6+

See thedocumentation site for details.

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Thank you! 🙏🏻

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This project is licensed under the MIT License. See theMIT LICENSE for details.

Copyright (c) John Hildenbiddle (@jhildenbiddle)