[CSS] use pseudo elements to implement some special images from baidu

[CSS] use pseudo elements to implement some special images from baidu
In css, there are four pseudo elements: first-line, first-letter, before, and after. The first two selected are the first text and the first letter in the target element. You can add extra styles to the element. Before and after are the most common pseudo elements, which are used differently from the first two, and are more useful.: Before,: after is used to add the specified content before and after the current element respectively. The example usage is as follows: copy the Code <! Doctype html>