This course will become read-only in the near future. Tell us at if that is a problem.



Surely if you have not yet read the W3 specs concerning CSS then they might be a little bit confusing at first. Let us break down the specs so that we can decipher their meanings in plain ol' english. Feel free to print the specs as they are print friendy of course.

In the W3C Process, a Recommendation-track document passes through five levels of stability, summarized below:

Working Draft (WD)
Published during the process of drafting the specification, the purpose of a public Working Draft is to create a snapshot of the specification's current state and to solicit input from the W3C and the public. The document is known to be unstable, and is often incomplete.

Last Call Working Draft (LC or LCWD)
By publishing a Last Call Working Draft, a working group is expressing that they consider the spec to be complete and all issues to be resolved. Publishing a Last Call Working Draft announces that this specification will move toward Candidate Recommendation unless significant issues are brought up. The Last Call period is a last chance for others to submit issues before the transition to CR.

Candidate Recommendation (CR)
By publishing a Candidate Recommendation, a working group is expressing that have resolved all known issues and they believe the spec is ready for implementation.

Proposed Recommendation (PR)
To exit CR and enter this stage, the spec needs a comprehensive test suite and implementation reports proving that every feature in the spec is interoperably implemented in at least two shipping implementations. Entering the Proposed Recommendation stage signals to the W3C that these requirements have been met. Once the W3C officially approves the specification, it becomes a Recommendation.

Recommendation (REC)
This is the final stage. At this point there should need to be no more changes.

CSS Explanation

CSS 2.1 Specs
W3 Status: Recommendation [ June 7, 2011 ]

CSS3 Specs :
CSS Level 3 builds on CSS Level 2 module by module, using the CSS2.1 specification as its core

what is the difference between an implementor and an author?

Web Designers who use CSS for presentation of HTML etc.

Browser Manufacturers(i.e. people who make the browsers)


How To Read W3 Specs
A List Apart :

Specification Document Language Guide:

  • CSS property and psuedo-class names are delimited by single quotes
  • CSS values are delimited by single quotes
  • HTML attributes are always delimited by double quotes

Task Discussion