Detailed explanation of CSS font size setting method

In CSS, you can use px, em, rem and other units to set the font size. The following will introduce the use of these units one by one.

1. Pixel unit - px

The pixel unit is the most commonly used unit. Because it has a fixed size and stable display effect, it is often used when setting the font size. The syntax is:

font-size: number px;

For example, the code to set the font size to 12px is:

font-size: 12px;

2. Relative unit - em

em is a relative unit, generally used to set the font size relative to the parent element. When using relative units throughout the page, if the HTML font size is first set to 16px, then 1em=16px. Of course, you can achieve different font sizes of parent elements by setting the font size of child elements. The syntax is:

font-size: number em;

For example, the code to set the font size to 1.5em For:

font-size: 1.5em;

3. Relative unit - rem

rem is a new relative unit in CSS3. Different from em, it is based on The root element (HTML element). Its syntax and usage are similar to em, except that the font size is relative to the root element. For example, the code to set the font size to 1.2rem is:

font-size: 1.2rem;

4. Percent unit - %

The percentage unit is also a relative unit, but Relative to the font size of the parent element or the entire page. Its syntax is:

font-size: number%;

For example, the code to set the font size to 80% is:

font-size: 80%;

Summary

When setting the font size, commonly used units are px, em, rem, and %. Among them, the pixel unit is the most commonly used because it can achieve fixed font size and stable display effect. Relative units can be flexibly applied according to specific situations. For example, em and rem can be used to control the font size relative to the parent element and root element, and % can be used to achieve the effect of scaling according to the parent element or the entire page font size.

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