The CSS Working Group has published a First Public Working Draft of CSS Box Model Module Level 4. This specification describes the margin and padding properties, which create spacing in and around a CSS box. It may later be extended to include borders (currently described in [css-backgrounds-3]).
CSS is a language for describing the rendering of structured documents (such as HTML and XML) on screen, on paper, etc.
Original source: https://www.w3.org/blog/news/archives/8452