In HTML5, rem is the abbreviation of "root em" and is a relative length unit; when the rem unit acts on non-root elements, it is relative to the font size of the root element. When the rem unit acts on the font size of the root element, , relative to its initial font size.
The operating environment of this tutorial: Windows 10 system, HTML5 version, Dell G3 computer.
What is rem in html5
In html5, rem is the abbreviation of "root em" and is a relative length unit.
Relative length units specify the properties of one length relative to another length. It is more suitable for different device relative lengths.
rem is the abbreviation of root em (root em). When rem acts on non-root elements, it is relative to the font size of the root element; when rem acts on the font size of the root element, it is relative to its initial font size.
Relative to the root element (i.e. html element) font-size multiple of the calculated value
The example is as follows:
<html>
<head>
<meta charset="utf-8">
<title>123</title>
<style>
/* 作用于根元素，相对于原始大小（16px），所以html的font-size为32px*/
html {font-size: 2rem}
/* 作用于非根元素，相对于根元素字体大小，所以为64px */
p {font-size: 2rem}
</style>
</head>
<body>
作用于根元素，相对于原始大小（16px），所以html的font-size为32px
<p>作用于非根元素，相对于根元素字体大小，所以为64px。</p>
</body>
</html>Output result:
Recommended tutorial: "html video tutorial"
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