selectors with colons

Question

what does :after or before mean

Answer 1

Before colon is used when you are referencing selectors in css like
.body:hover{
}
And after colon is used while referencing property like this
.body{
color:red;
}

Answer 2

before mean

Answer 3

there are pseudoclass than append some content after or before the target selector ej:
at css
p:before {
content : ">>";
}

at html
<p> Some text</p>

at browser

>>Some text