The standard selector has one type of text defined as a style.

The multiple selector has more

than one type of text as a style usage, such as different header sizes.

The contextual selector uses a special extra selector to define something inside another text type.

The contextual - child selector only works when it is a child of another such as this em inside of p.

A class selector is used when there is more than one instance of usage.

An id selector is used when there is only one instance of usage like this overline.

This is the second instance of the class usage such as this underline.

The universal selector applied the centering of all of the text.

The adjacent sibling selector applies to a text type adjacent to its parent like this small-caps h1 after the p.

A type of pseudo class in the first child, where only the first class element gets the style like these quotes.

A type of pseudo element is the first-letter, which only selects the first letter in a parent.

The Validator Links below have a Hover color change pseudo class.

The CSS Validator has its border width and padding defined by an Attribute Selector = "Valid CSS!"