Cascading Style Sheets (CSS) Working Group Charter

The mission of the group, part of the Style Activity, is to develop and maintain CSS.

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End date 30 November 2010, extended to 31 March 2011
Confidentiality Proceedings are Public
Initial Chairs Daniel Glazman, Peter Linss
Initial Team Contacts
(FTE %:65)
Bert Bos, Chris Lilley
Usual Meeting Schedule Teleconferences: Weekly
Face-to-face: 2 per year


The CSS WG develops the following, somewhat independent technologies:

An example of a language that uses only the syntax is STTS (developed by Disruptive Innovations). An example that uses the syntax, the cascading & inheritance, but not the typography model is the set of properties for styling SVG. CSS levels 1, 2 and 3 include the syntax, cascading & inheritance and rendering model.

CSS is a rather large and complex language. CSS beyond Level 2 is being developed as a set of modules each of which may advance on the W3C Recommendation Track independently. Among them are modules for syntax, cascading and inheritance, and, of course, many aspects of typography, page layout and presentation.

As individual CSS modules advance to REC, the Group periodically publishes a new snapshot of CSS. Each defines the set of CSS modules that are stable at that point.

Profiles are subsets of the features of CSS, usually for a specific kind of device. The CSS WG has published profiles for TV, mobile phones and low-end printers. The number of such profiles should stay as small as possible, but when needed, the working group tries to cooperate with the organizations that need the profiles.

The CSS WG not only develops CSS, but also checks that properties needed by other working groups and which could occur in a style sheet together with CSS properties, are compatible with CSS in general and consistent in their naming schemes. This affects properties such as those of SVG and Device Independence (such as media features), but not properties such as those in STTS nor the presentation attributes of XSL, SVG or DFXP.

Part of the work of the working group is also to develop test suites for the various specifications it publishes.

Another part is to maintain errata and, when needed, publish revised versions of the various specifications

Module List

The following existing modules are considered in scope for this charter period. The group focuses its efforts on the modules in the High Priority section, but may work on other modules listed here as time and resources allow.

More information about these modules, can be found on the group's wiki page

Success Criteria

The CSS Working Group's work is considered a success if there are multiple independent complete and interoperable implementations of its deliverables that are widely used.



The modules listed as High Priority are expected to become Recommendations within the timeframe of this Charter and to have errata actively maintained as needed.

As mentioned in the Modules list section, the Group may work on other modules as time and resources allow.

Other Deliverables

The Group creates a comprehensive test suite for each CSS module before it becomes Recommendation.

The Group monitors, tracks, and encourages implementation of CSS, both during Candidate Recommendation and afterwards.


The following is a list of known liaisons with other W3C groups at the time this charter was written. The group also coordinates with groups not listed here through the Hypertext Coordination Group.

Internationalization Activity
The Group liaises closely with the Internationalization Activity to ensure effective support for internationalization.
Scalable Vector Graphics (SVG) Working Group
The Group coordinates closely with the SVG WG on common features (such as the CSS Animations, CSS Fonts, CSS Object Model Level 3, CSS Transformations, and CSS Transitions Modules) to meet the needs of HTML/CSS, SVG, and mixed HTML/CSS/SVG content, and to ensure compatibility at the functionality level for ease of implementation and authoring.
Ubiquitous Web Applications (UWA) Working Group
The Group coordinates with the UWA WG for CSS modules affected by the UWA WG, in particular the Template Layout module.
Compound Document Formats (CDF) Working Group and the OMA
The CSS Mobile Profile is of interest to these groups.
XSL Working Group
The Group tries to harmonize names and behavior of features with the XSL WG.
WebApps Working Group
The Group reviews the Selectors API specification being developed by the WebApps WG.


To be successful, the group is expected to have 10 or more active participants for its duration. Effective participation is expected to consume one work day per week for each participant; two days per week for editors. The group allocates also the necessary resources for building Test Suites.

Participants are reminded of the Good Standing requirements of the W3C Process.


The Group holds weekly teleconferences and communicates on the member-only mailing list w3c-css-wg@w3.org (archive) for member-only communications and on the public mailing list www-style@w3.org (archive) for technical discussions.

The list of current members in the CSS WG is public.

Information about the group (deliverables, participants, face-to-face meetings, teleconferences, etc.) is available from the Cascading Style Sheets (CSS) Working Group page.

Decision Policy

As explained in the Process Document (section 3.3), this group seeks to make decisions when there is consensus. When the Chair puts a question and observes dissent, after due consideration of different opinions, the Chair should record a decision (possibly after a formal vote) and any objections, and move on.

When the Chair conducts a formal vote to reach a decision on a substantive technical issue, eligible voters may vote on a proposal one of three ways: for a proposal, against a proposal, or abstain. For the proposal to pass there must be more votes for the proposal than against. In case of a tie, the Chair decides the outcome of the proposal. The Chair must only conduct a formal vote during a group meeting, and at least two-thirds of participants in Good Standing must be in attendance.

Patent Policy

This Working Group operates under the W3C Patent Policy (5 February 2004 Version). To promote the widest adoption of Web standards, W3C seeks to issue Recommendations that can be implemented, according to this policy, on a Royalty-Free basis.

For more information about disclosure obligations for this group, please see the W3C Patent Policy Implementation.

About this Charter

This charter has been created according to section 6.2 of the Process Document. In the event of a conflict between this document or the provisions of any charter and the W3C Process, the W3C Process shall take precedence.

This charter replaces the previous charter.

Daniel Glazman, Peter Linss, Bert Bos

Created: 5 April 2008
Last modified: $Date: 2010/11/22 13:54:54 $