概述
:root 这个 CSS 伪类匹配文档树的根元素。对于 HTML 来说，:root 表示 <html> 元素，除了优先级更高之外，与 html 选择器相同。
语法
:root
示例
在声明全局 CSS 变量时 :root 会很有用：
:root {
--main-color: hotpink;
--pane-padding: 5px 42px;
}
规范
| Specification | Status | Comment |
|---|---|---|
| Selectors Level 4 :root |
Working Draft | No change |
| Selectors Level 3 :root |
Recommendation | Initial definition |
浏览器兼容性
We're converting our compatibility data into a machine-readable JSON format.
This compatibility table still uses the old format,
because we haven't yet converted the data it contains.
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| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 1 | (Yes) | 1.0 (1.7 or earlier) | 9 | 9.5 | 1.0 |
| Feature | Android | Edge | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | ? | (Yes) | ? | ? | ? | ? |