What is CSS3?

CSS3 is an extension of CSS 2.1 that adds powerful new functionality, but it’s no longer a single specification. Instead, it’s been divided up into several modules. Each module is a standalone specification for a subsection of CSS, like selectors, text, or backgrounds. Every module has its own set of authors and its own timetable. The advantage of this is that the entire CSS3 specification doesn’t have to be held up waiting for one little bit to get worked out—the module that that little bit is in can wait, while the rest moves forward.

You can see a list of all the modules, plus their current status on the path towards being finalized, at www.w3.org/Style/CSS/current-work. We’ll discuss the status of these modules later in this chapter, but for now let’s get right into what’s new and exciting in CSS3.