Pseudo-elements in CSS

 Pseudo-elements in CSS

Pseudo-elements are similar to pseudo-classes, but they allow you to add content to an element that is not in the HTML markup. For example, you can use the ::before and ::after pseudo-elements to add content before or after an element. Here's an example:

.box::before {

  content: "";

  display: block;

  width: 50px;

  height: 50px;

  background-color: blue;

}

This will add a blue square before the .box element.