CSS and Network Performance

This post by Harry does a great job of talking about the performance implications of CSS, and he shares a load of tips for avoiding big performance hits due to CSS.

CSS is critical to rendering a page—a browser will not begin rendering until all CSS has been found, downloaded, and parsed—so it is imperative that we get it onto a user’s device as fast as we possibly can. Any delays on the Critical Path affect our Start Render and leave users looking at a blank screen.