Pseudo-class 伪类
Structural Pseudo-Class 介绍结构伪类
Pseudo-class Selector 伪类选择符
Structural pseudo-classes and class selectors 结构伪类与类选择器
Style rule contains colon without pseudo class.
样式规则包含冒号而不包含伪类。
youdao
Using pseudo class selectors to change content?
使用伪类选择器来改变内容？
You can add a pressed button state with CSS by styling the active pseudo-class of the link in question.
你可以通过配置CSS中链接的active伪类来添加一个按下的按钮状态。
应用推荐
模块上移
模块下移
不移动