The Cascading Style Sheets (CSS) Standard

A specification is not a manual. There is no excuse for badly written prose and please complain if you find some. But specs do target a specific audience. If you need some guidance, read Understanding the CSS Specifications.

Stable Specifications

The following documents constitute the official, formal specifications for the Cascading Style Sheets (CSS) standard. We recommend starting with the current CSS Snapshot.

CSS Snapshot 2010: Defines (by referencing the appropriate specifications) CSS Level 1, CSS Level 2, and beyond, as of 2010.
CSS Level 2 Revision 1 (CSS2.1) and errata: Defines CSS Level 2 and forms the foundation for CSS Level 3.
CSS Color Module Level 3: Specifies the color-related aspects of CSS.
CSS Namespace Module: Defines syntax for declaring and using namespace prefixes.
Selectors Level 3: Defines selectors, which are used to select elements in an HTML or XML document.
Media Queries Level 3: Media queries detect properties of the medium to which the document is rendered, and can be used to target style rules to particular types of media.

Upcoming Specifications

Many specifications are still in the process of development. You can learn more about this work on the current work page and participate by contributing to the discussion and development of the CSS specs and test suites.

CSS Profiles

Profiles define a subset of CSS appropriate for a particular type of user agent.

CSS Mobile Profile 2.0: Defines a subset of CSS tailored to the needs and constraints of mobile devices.
CSS Print Profile 1.0: Defines a subset of CSS tailored to the needs and constraints of TV devices.
CSS TV Profile 1.0: Defines a subset of CSS tailored to the needs and constraints of print devices.

CSS-related APIs

Simple API for CSS (Parsing): SAC 1.0 is a standard interface for CSS parsers that is designed to work with CSS (all levels) and CSS-derived languages.
Document Object Model (DOM) Level 2 Style: DOM Level 2 Style is a platform- and language-neutral interface that allows programs and scripts to dynamically access and update the linking and content of style sheets.

Obsolete Specifications

CSS Level 2 (1998): This CSS2 specification is obsoleted by the CSS2.1 specification, which incorporates all the CSS2 errata and many other fixes and clarifications.
CSS Level 1 (1996/1999): This CSS1 specification is obsoleted by the CSS Level 1 definition in the CSS Snapshot, which states that CSS Level 1 is defined as all the features listed in this CSS Level 1 specification using the definitions in CSS2.1.

CSS Specification Status Codes

W3C indicates the stability of specifications by a status code. The CSS working group uses the following abbreviations, from least to most stable:

Abbreviation	Full name
WD	Working Draft
LC	Last Call
CR	Candidate Recommendation
PR	Proposed Recommendation
REC	Recommendation