:root
A selector that matches the very top-level element of the document (usually the <html> tag in a website). It's the standard place to define global CSS variables.
Quick example
:root {
/* The best place to define your design system variables */
--brand-color: #3498db;
--base-spacing: 1rem;
}:root Browser Support
Widely available Since 2015 96% global usage
This feature is well established and works across many devices and browser versions. It has been available across browsers since 2015.
Safe to use without fallbacks.
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