The :root
selector allows you to target the highest-level “parent” element in the DOM, or document tree. It is defined in the CSS Selectors Level 3 spec as a “structural pseudo-class”, meaning it is used to style content based on its relationship with parent and sibling content.
In the overwhelming majority of cases you’re likely to encounter, :root
refers to the<html>
element in a webpage. In an HTML document the html
element will always be the highest-level parent, so the behaviour of :root
is predictable. However, since CSS is a styling language that can be used with other document formats, such as SVG and XML, the :root
pseudo-class can refer to different elements in those cases. Regardless of the markup language, :root
will always select the document’s top-most element in the document tree.
In the example below, the :root
pseudo-class selector is used to create a background color behind the <body>
element. In this case, the same effect could be achieved by using thehtml
element selector in our CSS instead.
<p>We can take advantage of being able to apply CSS to the <code><html></code> element to skip the wrapper <code>div</code> and keep our markup clean!</p>
:root { background-color: cornflowerblue; padding: 3em; } body { background-color: white; padding: 1.5em; }
Points of Interest
- While the
:root
selector andhtml
selector both target the same HTML elements, it may be useful to know that:root
actually has a higher specificity. Pseudo-class selectors (butnot pseudo-elements) have a specificity equal to that of a class, which is higher than a basic element selector.
Browser Support
Chrome | Safari | Firefox | Opera | IE | Android | iOS |
---|---|---|---|---|---|---|
yep | yep | yep | 9.5+ | IE9+ | yep | yep |
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