8 August 2017  |  Archive The  CSS Working Group  invites implementations of  CSS Containment Module Level 1  Candidate Recommendation. This CSS module describes the  ‘contain’  property, which indicates that the element’s subtree is independent of the rest of the page. This enables heavy optimizations by user agents when used well. CSS  is a language for describing the rendering of structured documents (such as HTML and XML) on screen, on paper, in speech, etc.

The Cascading Style Sheets (CSS) Working Group has published Working Drafts of CSSOM and CSS Image Values and Replaced Content Module Level 3 . CSSOM defines APIs (including generic parsing and serialization rules) for Media Queries, Selectors, and CSS itself. The latter specification First, it defines the syntax for image values in CSS. It also defines properties used to control the interaction of replaced content and the CSS layout algorithms. These properties can affect the used image resolution for bitmaps, the replaced object's orientation, and whether and how to preserve the object's aspect ratio. Learn more about the Style Activity .