CSS3 Introduction

is fully backwards compatible with CSS3, so you don’t have to change your existing design. Browsers will always support CSS2.

CSS3 Modules

CSS3 is split into "modules". Old specifications have been broken into small pieces and new ones have been added.

Some of the most important CSS3 modules are as follows:

Selector

Box model

Background and border

Text effects

2D/3D conversion

Animation

Multi-column layout

User interface

CSS3 Recommendation

The W3C CSS3 specification is still there development.

However, many new CSS3 properties are available in modern browsers.