There are plenty of ways to make websites run faster. In this section, you can discover performance best practices that real web professionals employ in their everyday work. These practices have improved the user experience for millions of users and we hope they are going to be useful for other web developers.

CSS: Using every declaration just once
Using every CSS declaration only once is an effective way to reduce file size of style sheets. It’s not a trivial optimization technique though: Watch over the cascade and adjust your editing workflow.
How gzip …