What are CSS pseudo-classes
A keyword added to selectors that specifies a special state of the element to be selected
What does a CSS pseudo-class consist of
A selector followed by colon and a keyword
CSS Pseudo-Class: hover
The hover pseudo-class targets elements that have a mouser pointer hover over them
CSS Pseudo-Class: valid
The valid pseudo-class targets input controls that have valid input
CSS Pseudo-Class: invalid
The invalid pseudo-class targets input controls that invalid input
CSS Pseudo-class: required
The required pseudo-class targets input controls that require user input
CSS Pseudo-class: optional
The optional pseudo-class targets input controls that are optional