Selector Type Efficiency There are four main types of selectors in CSS–ID, class, tag and universal. IDs are unique elements denoted by the hash, like our old friend #current.

Listing 1. Using the :has pseudo-class (example 1) div:has (span) That’s pretty useful already, as a way to select elements up the selector chain, but there is more.

I recommend learning id, class name and HTML tag selectors first. The id selector matches HTML elements with the same id. It's often used when you want to locate a specific element in the Document ...