HTML: the Root Element

What is Root Element

• root element of HTML is the element represented by the html tag.
• Root element of XML may be other, depending on the XML. For example, root element of SVG is represented by the svg tag. [see Practical SVG Tutorial]
• Root element of Atom Webfeed is feed.

Why is Root Element Important

It's important because many CSS unit's meaning refers to it.

[see CSS: Length Units]

CSS Syntax for Root Element

In CSS, the root can be specified by: :root

For example, make all text red:

:root { color: red; }

This is often used when using CSS variables.

[see CSS Variable]