What does the em tag in css mean?-CSS Tutorial-php.cn

EM in CSS represents a length unit relative to the current font size, denoted as "em" (for example, font-size: 1.2em;). It differs from PX (Pixels) and REM (Root EM) in that it is relative, relative to the current font size, whereas PX is absolute, representing screen pixels, and REM is relative to the font size of the document's root element. EM is used to adjust text size and spacing to resize text based on user preferences, create responsive designs, and define space between elements.

What does the em tag in css mean?

The meaning of EM tag in CSS

EM is a unit in CSS, indicating a relative to the current The length of the font size.

How to use EM

The EM value is followed by the letter "m", for example:

font-size: 1.2em;

Copy after login

This sets the font size of the text to the current font size 1.2 times.

The difference between EM and PX and REM

PX (pixel)is an absolute unit that represents the physical pixels on the screen.
EMis a relative unit, relative to the current font size.
REM (root EM)is also a relative unit, but it is relative to the font size of the root element of the document.

When to use EM

EM is suitable for resizing and spacing text without changing its proportions. It's especially useful for:

Resizing text based on user preferences
Creating responsive designs that automatically adapt to different screen sizes
Defining the space between elements

Example

body { font-size: 16px; } h1 { font-size: 2em; /* 相对于正文文本的 2 倍 */ } p { margin-bottom: 1em; /* 相对于正文文本的 1 倍 */ }

Copy after login

The above code will:

Set the font size of the body text to 16px
will Set the font size of the h1 tag to 2 times the body text
Set the margin under the p tag to 1 times the body text

The above is the detailed content of What does the em tag in css mean?. For more information, please follow other related articles on the PHP Chinese website!