If HTML is about bringing meaning to content, CSS is about defining how our content looks — the layout and positioning of elements, the colors, the typography and other visual effects.

Understanding how browsers parse CSS and render websites is an important first step towards writing more efficient code. In this first piece on efficient CSS, we look at selectors, how the browser ...

If you haven't checked out CSS, understanding the most often used core selectors is a good place to start.

The group recently published the Last Call Working Draft of "Selectors API," which are widely used in CSS, and are patterns that match against elements in a tree structure.