Pseudo-Elements: ::before, ::after and ::marker

Pseudo-elements style a part of an element, or add decoration before or after it, such as a play icon, a quote mark, a list's numbers, a text box's placeholder or highlighted text, without changing the HTML.

Updated

Cheat sheet: Pseudo-Elements: ::before, ::after and ::marker
Category
CSS
Level
Apprentice
Tags
::after, ::before, ::marker, CSS, placeholder, Pseudo-element