The World Wide Web Consortium Issues CSS2 as a W3C Recommendation
http://www.w3.org/ -- 12 May, 1998 -- Leading the Web to its full potential, the World Wide Web Consortium (W3C) has today released the CSS2 (Cascading Style Sheets, level 2) specification as a W3C Recommendation. The CSS2 specification represents a cross-industry agreement on a wide range of features for richer and more accessible Web pages. CSS2 builds upon W3C's earlier Recommendation for CSS1, adding many new features while remaining fully backwards compatible. A W3C Recommendation indicates that a specification is stable, contributes to Web interoperability, and has been reviewed by the W3C Membership, who are in favor of its adoption by the industry.
The CSS2 specification was written and developed by the W3C Cascading Style Sheets and Formatting Properties (CSS&FP) Working Group, which includes key industry players such as Adobe Systems, Bitstream, Electricité de France, Hewlett Packard, IBM, Lotus, Macromedia, Microsoft, Netscape, NIST, Novell, Silicon Graphics, and SoftQuad; content specialists and invited experts in the fields of typography, accessibility, and internationalization; and document publishing input from Apple, Hotwired, the Productivity Works, and Studio Verso. CSS2 has also benefited from detailed review by the style sheet-using and content-creation communities, through public mailing lists.
"Today's release of the CSS2 specification demonstrates the effectiveness of the W3C process and is the culmination of more than a year's work," said Chris Lilley, chair of the CSS&FP Working Group. "CSS2 lets Web designers create compelling documents, dynamic and design-rich, that also enhance accessibility and contribute to internationalization."
CSS2 has powerful design capability
In the past, designers have achieved amazing results with HTML alone, for instance, by using tables to simulate margins and transparent images to gain some control over whitespace. Often, this had the unfortunate effect of locking the content into fixed assumptions of window width and font size. CSS1 allows designers to produce the same effects more easily and simply, with finer control and flexibility in areas such as line spacing and justification.
CSS2 includes all the capabilities of CSS1 and adds improved typographic control, including dynamically downloadable fonts. There are new positioning properties to control layout; for example, to produce sidebars and navigation areas. Images and text can be layered and overlapped and can be dynamically moved around the screen with scripts. CSS2 also adds control over table layout, particularly useful for XML documents, and allows the automatic numbering of headings and lists.
"CSS2 will take Web design to new places," said Håkon Lie, W3C Style Sheets Activity Leader who, in 1994, first proposed the concept of Cascading Style Sheets. "CSS1 did a fine job of replicating HTML extensions through style sheets. CSS2 does more than just capture existing practice: it greatly expands the Web designer's palette."
CSS2 makes the Web faster
On the Web today, it's common to create images of text in order to control fonts and colors. Images are much bigger than text, and the perceived slowness of the Web can, in part, be attributed to this practice. Web pages also commonly contain large numbers of repeated presentational markup, which makes the pages unnecessarily large. CSS2 allows authors to express the same rich styles, but is compact and text-based. Pages that use CSS2 have been shown to be significantly smaller and to load much faster than comparable image-based pages.
CSS2 enables cross-media publishing
The W3C Recommendation for CSS2 comes at a time when the same Web content needs to be accessible and compelling on an increasingly broad range of devices, from smart televisions to cellular phones, and from in-car systems to distributed print bureaus. Content creators can no longer afford to have their work limited by fixed assumptions about the display. CSS2 provides solutions for cross-media publishing and graceful repurposing of information.
CSS2 provides built-in accessibility
A side effect of reliance on tables for layout and images of text for typography has been a reduction in accessibility of Web pages for people surfing with image downloads turned off and for visually impaired users browsing with screen readers. Moving toward CSS removes presentational clutter from documents, automatically increasing accessibility without compromising visual design, and removes the necessity for hard-to-maintain separate "text-only" pages.
"The advanced presentation capabilities offered by CSS2 provide page designers full creative control without sacrificing accessibility for Web users who have disabilities," said Judy Brewer, Director of W3C's Web Accessibility Initiative International Program Office. "In particular, CSS2 introduces improved user control for layout, cascade priorities, support for varied media types, and aural cascading style sheets to control voice inflection."
CSS2 aids internationalization
There is an increasing need for the effective presentation of Web pages in languages other than English, and for presentation of documents in multiple languages. Matters such as writing direction, font styles, and quoting conventions differ from one written language to another. CSS2 makes significant steps toward being able to display multilingual documents well.
CSS2 works well with XML
To date, CSS1 primarily has been applied to HTML documents, although it has also been used with content written in XML. CSS2 adds features specifically targeted at displaying XML documents since these have no built-in semantics or presentational features; style sheets are thus essential for the deployment of XML content.
Further information on CSS can be found at http://www.w3.org/Style/css.
About the World Wide Web Consortium [W3C]
The W3C was created to lead the Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability. It is an international industry consortium jointly run by the MIT Laboratory for Computer Science (LCS) in the USA, the National Institute for Research in Computer Science and Control (INRIA) in France and Keio University in Japan. Services provided by the Consortium include: a repository of information about the World Wide Web for developers and users; reference code implementations to embody and promote standards; and various prototype and sample applications to demonstrate use of new technology. To date, more than 255 organizations are Members of the Consortium.
For more information about the World Wide Web Consortium, see http://www.w3.org/
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"Inclusion of aural cascading style sheets (ACSS) in CSS2 brings one step closer the vision of ubiquitous information access in a manner best suited to the user's needs. Motivated initially by the need to present Webformation efficiently to users with visual impairments (see Emacspeak for the first ACSS enabled user environment) -- ACSS will have a significant impact on the use of the WWW by functionally blind users such as automobile drivers wishing to browse information when on the road. Like the invention of the telephone (which was a direct consequence of work on hearing aids) ACSS once again proves the benefits of work on alternative interfaces to all users."-- T. V. Raman, Advanced Technology Group, Adobe Systems Incorporated
"Together with W3C and NIST, Case Western Reserve University has established a CSS1 test suite. This suite is provided freely and openly to browser developers and Web designers alike, so that they may test current and upcoming implementations of CSS support. Testing will soon expand to cover CSS2 as well, and will be improved over time by community feedback and input. CWRU is proud of its role in creating this suite, and we hope it will be useful to the Web community as a whole."-- Eric A. Meyer, Hypermedia Systems Manager, Case Western Reserve University
"Electricité de France, the largest electricity producer in the world, believes that CSS 2 is a major spec that will help us building, managing and distributing our internal documents, and will make the distribution of our on-line corporate information easier. We are now waiting for vendors' support and expect from their tools a full conformance to the specification. We'd like to congratulate W3C for this spec and especially for the Aural Style Sheets section."-- Jean-Marie Bernard, Chief of Data Processing and Applied Mathematics Department, Electricité de France
"CSS2 is a major step forward in bringing precise control of visual design to the web. As members of the W3C and as an active participant in the CSS working group, Macromedia is committed to increasing the web's expressiveness and helping to develop leading-edge tools that support the W3C standards for web designers."-- Sho Kuwamoto, Senior Software Engineer, Macromedia Dreamweaver
" W3C has successfully moved a critical standard forward with CSS2. Microsoft is committed to standards and provides leading support for CSS today in Internet Explorer 4.0."-- David Cole, Vice President of Web Client and Consumer Experience Division, Microsoft
"Today's announcement regarding the Cascading Style Sheets 2 specification (CSS2) is great news for Internet users and the Internet developer community at large. CSS provides a style sheet language which gives developers and users rich control over the display of HTML and XML documents. As the first commercial product to demonstrate the use of Cascading Style Sheets with both HTML and XML in the source code for Netscape Communicator 5.0, Netscape continues to recognize the importance of open standard technology and the role the W3C plays in its development. Netscape looks forward to supporting CSS2 in a future version of Communicator."--Jim Hamerly, Vice President, Client Products, Netscape
"CSS2 will vastly improve the ability of an HTML authors and users to obtain the formatting results they desire without recourse to awkward HTML constructs never intended for the purpose. In addition, CSS2's inclusion of support for aural style sheets will be important for both the visually impaired as well as those who need to get information without reading a computer screen or printout."-- Douglas Rand, Technical Staff, Web Publishing, Silicon Graphics, Inc.
"SoftQuad has always been committed to providing standards-based solutions to our customers. The new CSS2 specification represents an important milestone in defining interoperable style formats for use on the web. The style sheet language includes many important features and functions web authors have been asking for. We are committed to providing more CSS support in our authoring tools."-- Lauren Wood, Technical Product Manager, SoftQuad, Inc.
"With CSS2 and the Core Styles, CSS moves beyond the 'good idea' phase and becomes a critical element of a new, more attractive, and manageable Web, where substance and style complement one another as peers."-- Todd Fahrner, Studio Verso
"Electricité de France, premier producteur électrique au monde, est convaincue de l'intérêt majeur de la spécification CSS 2 qui nous aidera à construire, gérer et publier nos ensembles documentaires internes et facilitera notre communication externe en ligne. Nous attendons désormais l'intégration de ce standard par les éditeurs de logiciels et espérons une conformité totale à la spécification. Nous adressons au W3C nos félicitations pour cette spécification, et plus particulièrement pour la section Aural Style Sheets."-- Jean-Marie Bernard, Chef du Service Informatique et Mathématiques Appliquées, Electricité de France
"Les functionalités de présentation avancées offertes par CSS2 donnent aux créateurs de pages Web un contrôle très étendu sans sacrifier pour autant l'accés au Web pour les utilisateurs handicapés. En particulier, CSS2 améliore le contrôle de l'utilisateur final sur la mise en page, l'ordre de chargement des feuilles de styles, un meilleur support pour plusieurs types de media, et un nouvel ensemble de propriétés pour les présentations audio."--Judy Brewer, Directeur du Programme International du WAI (Web Accessibility Initiative du W3C)
CSS gives content creators, designers and readers the power tools they need to realize the full potential of the their HTML and XML documents. CSS2 includes all the power of CSS1, and adds enhancements in several areas to make the Web more appealing for both content providers and users.
The CSS2 Recommendation is based upon CSS1, a W3C Recommendation issued in December 1996, and is a prerequisite for the Document Object Model (DOM), W3C's platform- and language-neutral interface, which allows programs and scripts to dynamically access and update the content, structure, and style of documents.
Improved design capabilities
CSS2 offers precise control over the presentation of Web pages. The ability to position elements explicitly greatly enhances control of document layout, both on screen and in print. Relatively positioned elements are shifted, by an amount specified by the designer, from the position they would have occupied in normal flow. Absolutely positioned elements are taken out of the normal flow of text entirely, and can be placed elsewhere to create navigation bars, indexes, and similar features. Floated elements can be used to place text or graphics in the margins, with text flowing around the floated element.
CSS2 has a rich WebFonts capability, offering dynamic download of fonts from a Web site (just as images are downloaded today). The fonts can be locked to a particular Web site and are not installed on the client machines. WebFonts also includes the information needed to synthesize fonts or to select similar looking fonts on the client, if the fonts specified by the designer are not available.
CSS selectors, which determine what style rules are applied to which parts of the document, have been made more powerful in CSS2. This gives designers greater flexibility and expressive power, particularly when styling XML documents.
Fast and maintainable sites
Prior to style sheets, the markup needed to simulate common typographic effects such as exdented headings, wide margins, and drop capitals caused documents to bloat and tied them to a single style of presentation. For example, without style sheets, to make all headings appear in a particular font, extra markup must be placed around every single heading in the document. It is easy to miss one heading, giving an inconsistent look. Redesigning such a document implies changing all of the tags.
"Consolidating all the presentation information into one part of the document, and not having to repeat it, makes the document shorter and simpler to edit," explained Chris Lilley, chair of the CSS&FP working group that produced CSS2. "Moving it into a separate style sheet is even better, allowing re-use and easing maintenance."
The separation of style and content allows a single style sheet to define the style for a group of related Web pages, or even an entire Web site. The result is shorter documents, which in turn, load faster. Once the first document has loaded, the rest are even faster because the browser need only fetch the style sheet once. A recent W3C study showed that using CSS with W3C's Portable Network Graphics (PNG) and HTTP/1.1 can dramatically reduce page download times and ease the load on the global Internet.
Write once, read anywhere
CSS2 introduces the concept of named media. Portions of a style sheet can be marked as only applying to certain media. For example, one part of a style sheet can set colors just for the screen, one part can set margins for when the page is printed, and the rest can specify what is common to both screen and print media.
Audio presentation of Web content -- using speech synthesis -- is an attractive alternative for accessing information, particularly suitable for home entertainment, industrial and medical information systems, and in-car browsers. CSS2 allows designers to control how HTML and XML documents are spoken, including the volume, speed, stress, and richness of the computer generated voices. The stereo position of voices, audio clips, and background music can also be controlled with CSS2.
Accessible to all
Besides the significant increase in accessibility of Web pages that use style sheets, CSS2 includes a number of specific features that improve accessibility. Users, as well as document authors, can specify style sheets; these are cascaded together to produce the end result. User style sheets can range from simple (e.g., increasing the overall size of the text) to complex (e.g., specifying full aural rendering). The ability to select elements with particular attributes and to generate content allows users to specify that, for example, alternate text ("alt" text) or titles on images should be displayed. Auto numbering of headings can also be a useful navigation aid.
Continuing the W3C goal of ensuring a truly World Wide Web, the members of the W3C CSS&FP Working Group drew on the experience of leading experts on internationalization and fonts. To accommodate internationalization, CSS2 fully supports the international ISO 10646 character set, allowing authors to manage differences in language, text direction, and character encoding schemes. CSS2 can display left-to-right, right-to-left, or mixed text such as a Hebrew document, containing a French quote, which itself contains a phrase in Arabic.
CSS2 enables document authors to apply specialized formatting to portions of documents depending on the language in which they are written. Font sets can be constructed to display multilingual documents. CSS2 extends list numbering to allow additional international styles. In addition, CSS2, when coupled with internationalization features, makes it easier to seach through content.
The CSS2 Package
The CSS2 Recommendation is supported by the W3C CSS2 Package, consisting of the CSS2 Validation Service, a set of W3C Core Style Sheets, and the CSS Test Suite. The CSS2 Package will help document authors use CSS2 and also help developers create CSS2-compliant software.
W3C CSS2 Validation Service
Today, W3C expanded its HTML Validation Service to include full CSS validation (both levels 1 and 2) at http://jigsaw.w3.org/css-validator. Content providers can be sure their style sheets are valid, either by giving the Web address or by pasting the style sheet into a form.
The service outputs error and warning messages, suggests style sheet improvements, and formats the corrected style sheets so they are easy to read.
"Browsers silently ignore style sheet errors, doing their best to work around errors," said Bert Bos, co-architect of CSS and one of the editors of the CSS2 Recommendation. "That's good for the user but doesn't help authors correct bugs. The best way to know whether your style sheets are correct is to run them by the CSS Validation Service."
W3C CSS Core Style Sheets
The Core Style Project proposes a modular architecture for Web style sheets. It builds upon the CSS1 Base Style Sheet incorporated into the CSS2 Recommendation. The project aims to promote cascadability among Web style sheets of diverse origins by providing style authors with generic, yet attractive models and bases for their own elaboration.
Shared CSS style sheets offer benefits to Web site developers, content providers, and users alike. Style sheet reuse means less site management and more consistent appearance. Consistency sends a strong message about corporate identity. It also improves accessibility by making it easier to navigate the site. Shared styles free content providers from the burden of rewriting style rules for each document. The cascade gives them the best of both worlds: reuse and extensibility.
"With CSS2 and the Core Styles," said Todd Fahrner, the Studio Verso designer behind the Core Style Sheets, "CSS moves beyond the 'good idea' phase and becomes a critical element of a new, more attractive and manageable Web, where substance and style complement one another as peers."
The W3C Core Style Sheets page (http://www.w3.org/StyleSheets/Core/) explains how to link to the style sheets and provides samples that illustrate the effects of the Core Styles. W3C will continue to add to these Core Styles and intends to make css.w3.org a gallery of style sheets contributed by Web designers for communal consumption.
W3C CSS Test Suite
To ensure that pages designed with CSS work best on any browser, W3C is releasing a reference suite of CSS test documents (http://www.w3.org/Style/CSS/Test).
"The W3C CSS Test Suite is a tool for implementors to ensure interoperability with other CSS-based software," said Eric Meyer of Case Western Reserve University, who is coordinating the test suite efforts. "Key contributions from Tim Boland of NIST, W3C and the Web community have produced a test suite that covers all of CSS1". The Test Suite will be completed with CSS2 test documents in the near future.
Implementors can conduct tests on their CSS clients (authoring tools, browsers, format converters, etc.) by reading test suite documents and verifying the results against the expected rendering described in the test suite.
W3C Recommendation Process
Specifications developed within W3C working groups must be formally approved by the Membership. Consensus is reached after a specification has proceeded through the following review stages: Working Draft, Proposed Recommendation, and Recommendation.
Working Drafts are written by a Working Group, who typically meet by teleconference every week and also meet in person four to six times a year. Once stable, working drafts are submitted by working groups to the W3C Director for consideration as a Proposed Recommendation. Upon the Director's approval, the document becomes a Proposed Recommendation and is forwarded to the W3C Membership, who votes whether it should become an official W3C Recommendation. The W3C Advisory Committee -- comprised of one official representative from each Member organization -- submits one of the following votes on the Proposed Recommendation: yes; yes, with comments; no, unless specified deficiencies are corrected; no, this Proposed Recommendation should be abandoned.
During the Member review and voting period (approximately 6 weeks), the Working Group resolves minor technical issues (if any) and communicates its results to the W3C Director. After this time, the Director announces the disposition of the document; it may become a W3C Recommendation (possibly with minor changes), revert to Working Draft status, or may be dropped as a W3C work item.