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Fact Sheet: CSS2 Recommendation

From: Sally Khudairi <khudairi@w3.org>
Date: Tue, 12 May 1998 14:58:17 -0400
Message-ID: <35589BC9.80E08A4@w3.org>
To: w3c-news@w3.org
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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. 

  The CSS2 specification has been produced as part of
  the W3C Style Activity. For further information about
  CSS, see http://www.w3.org/Style/css/ 

  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. 

  Internationalization 

  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.
Received on Tuesday, 12 May 1998 14:58:19 UTC

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