::before and ::after are CSS pseudo elements. They can add content before or after that element. This is the syntax

.class::after {
  content: "some content"
}

This can be used with pseudo classes to add content when an event occurs. In the example below text is added when there is a hover event.

The ::before and ::after pseudo elements can also be added with no content content:"" and can be used to add styles to the document. The below example shows how you can add a border when hovering with ::after and the transition property.

What else can you do with ::before and ::after? Leave a comment below