CSS3 is split into "modules". The old specification has been split into smaller pieces and new ones have been added.
Some of the most important CSS3 modules are as follows:
- Box model
- Background and border
- Text effects
- 2D /3D conversion
- Multi-column layout
- User interface
The W3C's CSS3 specification is still under development.
However, many new CSS3 attributes are already used in modern browsers.