CSS Current Status

This page summarizes the relationships among specifications, whether they are finished standards or drafts. Below, each title links to the most recent version of a document.

Completed Work

W3C Recommendations have been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and are endorsed by the Director as Web Standards. Learn more about the W3C Recommendation Track.

Group Notes are not standards and do not have the same level of W3C endorsement.



CSS Namespaces Module Level 3

This CSS Namespaces module defines the syntax for using namespaces in CSS. It defines the @namespace rule for declaring the default namespace and binding namespaces to namespace prefixes, and it also defines a syntax that other specifications can adopt for using those prefixes in namespace-qualified names.


CSS Style Attributes

Describes the syntax and interpretation of the CSS fragment that can be used in "style" attributes inside mark-up, e.g., in HTML, SVG and MathML.


Selectors API Level 1

Selectors, which are widely used in CSS, are patterns that match against elements in a tree structure [SELECT][CSS21]. The Selectors API specification defines methods for retrieving Element nodes from the DOM by matching against a group of selectors. It is often desirable to perform DOM operations on a specific set of elements in a document. These methods simplify the process of acquiring specific elements, especially compared with the more verbose techniques defined and used in the past.


Media Queries

HTML4 and CSS2 currently support media-dependent style sheets tailored for different media types. For example, a document may use sans-serif fonts when displayed on a screen and serif fonts when printed. ‘screen’ and ‘print’ are two media types that have been defined. Media queries extend the functionality of media types by allowing more precise labeling of style sheets.

A media query consists of a media type and zero or more expressions to limit the scope of style sheets. Among the media features that can be used in media queries are ‘width’, ‘height’, and ‘color’. By using media queries, presentations can be tailored to a specific range of output devices without changing the content itself.


Selectors Level 3

Selectors are patterns that match against elements in a tree. Selectors have been optimized for use with HTML and XML, and are designed to be usable in performance-critical code.

CSS (Cascading Style Sheets) is a language for describing the rendering of HTML and XML documents on screen, on paper, in speech, etc. CSS uses Selectors for binding style properties to elements in the document. This document describes extensions to the selectors defined in CSS level 2. These extended selectors will be used by CSS level 3.

Selectors define the following function:

 expression ∗ element → boolean 

That is, given an element and a selector, this specification defines whether that element matches the selector.

These expressions can also be used, for instance, to select a set of elements, or a single element from a set of elements, by evaluating the expression across all the elements in a subtree. STTS (Simple Tree Transformation Sheets), a language for transforming XML trees, uses this mechanism. [STTS]


CSS Color Module Level 3

CSS (Cascading Style Sheets) is a language for describing the rendering of HTML and XML documents on screen, on paper, in speech, etc. It uses color related properties and respective values to color the text, backgrounds, borders, and other parts of elements in a document. This specification describes color values and properties for foreground color and group opacity. These include properties and values from CSS level 2 and new values.


A MathML for CSS Profile

This document describes a profile of MathML 3.0 that admits formatting with Cascading Style Sheets.


Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification

CSS 2.1 is derived from and is intended to replace CSS2. It supports media-specific style sheets so that authors may tailor the presentation of their documents to visual browsers, aural devices, printers, braille devices, handheld devices, etc. It also supports content positioning, table layout, features for internationalization and some properties related to user interface. CSS 2.1 corrects a few errors in CSS2 (the most important being a new definition of the height/width of absolutely positioned elements, more influence for HTML's "style" attribute and a new calculation of the 'clip' property), and adds a few highly requested features which have already been widely implemented. But most of all CSS 2.1 represents a "snapshot" of CSS usage: it consists of all CSS features that are implemented interoperably at the date of publication of the Recommendation.


Associating Style Sheets with XML documents 1.0 (Second Edition)

This document allows a style sheet to be associated with an XML document by including one or more processing instructions with a target of xml-stylesheet in the document's prolog.


Cascading Style Sheets (CSS1) Level 1 Specification


Document Object Model (DOM) Level 2 Style Specification

This specification defines the Document Object Model Level 2 Style Sheets and Cascading Style Sheets (CSS), a platform- and language-neutral interface that allows programs and scripts to dynamically access and update the content and of style sheets documents.

Group Notes


Ready-made Counter Styles

This document describes numbering systems used by various cultures around the world and can be used as a reference for those wishing to create user-defined counter styles for CSS.


CSS Snapshot 2017

This document collects together into one definition all the specs that together form the current state of Cascading Style Sheets (CSS) as of 2017. The primary audience is CSS implementers, not CSS authors, as this definition includes modules by specification stability, not Web browser adoption rate.


TTML Media Type Definition and Profile Registry

This document defines the application/xml+ttml media type and provides a registry of identified TTML processor profiles.


CSS Snapshot 2015

This document collects together into one definition all the specs that together form the current state of Cascading Style Sheets (CSS) as of 2015. The primary audience is CSS implementers, not CSS authors, as this definition includes modules by specification stability, not Web browser adoption rate.


CSS Template Layout Module

CSS is a simple, declarative language for creating style sheets that specify the rendering of HTML and other structured documents. This specification is part of level 3 of CSS (“CSS3”) and contains features to describe layouts at a high level, meant for tasks such as the positioning and alignment of “widgets” in a graphical user interface or the layout grid for a page or a window, in particular when the desired visual order is different from the order of the elements in the source document. Other CSS3 modules contain properties to specify fonts, colors, text alignment, list numbering, tables, etc.

The features in this module are described together for easier reading, but are usually not implemented as a group. CSS3 modules often depend on other modules or contain features for several media types. Implementers should look at the various “profiles” of CSS, which list consistent sets of features for each type of media.


CSS Print Profile

This specification defines a subset of Cascading Style Sheets Level 2, revision 1 [CSS21] and CSS3 Module: Paged Media [PAGEMEDIA] for printing to low-cost devices. It is designed for printing in situations where it is not feasible or desirable to install a printer-specific driver, and for situations were some variability in the output is acceptable.

This profile is designed to work in conjunction with XHTML-Print [XHTMLPRINT] and defines a minimum level of conformance as well as an extension set that provides stronger layout control for the printing of mixed text and images, tables and image collections.


Requirements for Japanese Text Layout

Describes requirements for general Japanese layout realized with technologies like CSS, SVG and XSL-FO. The document is mainly based on a standard for Japanese layout, JIS X 4051, however, it also addresses areas which are not covered by JIS X 4051.


Cascading Style Sheets (CSS) Snapshot 2007

This document collects together into one definition all the specs that together form the current state of Cascading Style Sheets (CSS). The primary audience is CSS implementors, not CSS authors, as this definition includes modules by specification stability, not Web browser adoption rate.


Cascading Style Sheets (CSS) Snapshot 2010

This document collects together into one definition all the specs that together form the current state of Cascading Style Sheets (CSS) as of 2010.


CSS Techniques for Web Content Accessibility Guidelines 1.0

This document describes techniques for authoring accessible Cascading Style Sheets (CSS). Cascading Style Sheets are defined by the W3C Recommendations "CSS Level 1" [CSS1] and "CSS Level 2" [CSS2]. This document is intended to help authors of Web content who wish to claim conformance to "Web Content Accessibility Guidelines 1.0" ([WCAG10]). While the techniques in this document should help people author CSS that conforms to "Web Content Accessibility Guidelines 1.0", these techniques are neither guarantees of conformance nor the only way an author might produce conforming content.

This document is part of a series of documents about techniques for authoring accessible Web content. For information about the other documents in the series, please refer to "Techniques for Web Content Accessibility Guidelines 1.0" [WCAG10-TECHS].

Note: This document contains a number of examples that illustrate accessible solutions in CSS but also deprecated examples that illustrate what content developers should not do. The deprecated examples are highlighted and readers should approach them with caution -- they are meant for illustrative purposes only.


List of suggested extensions to CSS


Below are draft documents: Candidate Recommendations, Last Call Drafts, other Working Drafts . Some of these may become Web Standards through the W3C Recommendation Track process. Others may be published as Group Notes or become obsolete specifications.

Candidate Recommendations


CSS Grid Layout Module Level 1

The Grid Layout module of CSS allows designers to define invisible grids of horizontal and vertical lines. Elements from a document can then be anchored to points in the grid, which allows them to be visually aligned to each other, even if they are not next to each other in the source.



While encodings have been defined to some extent, implementations have not always implemented them in the same way, have not always used the same labels, and often differ in dealing with undefined and former proprietary areas of encodings. This specification attempts to fill those gaps so that new implementations do not have to reverse engineer encoding implementations of the market leaders and existing implementations can converge.


CSS Basic User Interface Module Level 3 (CSS3 UI)

This section is informative.

CSS (Cascading Style Sheets) is a language for describing the rendering of HTML and XML documents on screen, on paper, in speech, etc. It uses various selectors, properties and values to style basic user interface elements in a document. This specification describes those user interface related selectors, properties and values that are proposed for CSS level 3 to style HTML and XML (including XHTML and XForms). It includes and extends user interface related features from the selectors, properties and values of CSS level 2 revision 1 and Selectors specifications.


CSS Fragmentation Module Level 3

This CSS module defines the style properties that specify the points in a document where text may be broken to start a new page, a new column, or any similar kind of region.


CSS Scroll Snap Module Level 1

The Scroll Snap Points Module defines CSS properties to control some aspects of the scrolling behavior when displayed content is too large for its box. In particular, it allows content to “snap” to certain preferred positions while scrolling, e.g., between lines rather than in in the middle of one.


CSS Values and Units Module Level 3

This CSS3 module describes the various values and units that CSS properties accept. Also, it describes how values are computed from "specified" (which is what the cascading process yields) through "computed" and "used" into "actual" values. The main purpose of this module is to define common values and units in one specification which can be referred to by other modules. As such, it does not make sense to claim conformance with this module alone.


CSS Flexible Box Layout Module Level 1

The draft describes a CSS box model optimized for interface design. It provides an additional layout system alongside the ones already in CSS. [CSS21] In this new box model, the children of a box are laid out either horizontally or vertically, and unused space can be assigned to a particular child or distributed among the children by assignment of “flex” to the children that should expand. Nesting of these boxes (horizontal inside vertical, or vertical inside horizontal) can be used to build layouts in two dimensions.


CSS Cascading and Inheritance Level 3

This CSS3 module describes how values are assigned to properties. CSS allows several style sheets to influence the rendering of a document, and the process of combining these style sheets is called “cascading”. If no value can be found through cascading, a value can be inherited from the parent element or the property's initial value is used.


CSS Cascading and Inheritance Level 4

By way of cascading and inheritance, values are propagated for all properties on all elements. New in level 4 are the 'default' keyword and for the @import rule.


CSS Writing Modes Level 3

This module specifies the text layout model in CSS and the properties that control it. It covers bidirectional and vertical text.


CSS Custom Properties for Cascading Variables Module Level 1

This module contains features of CSS relating to variables. A variable is a type of value that is accepted by all properties and several properties can share the same variable.


CSS Will Change Module Level 1

The 'will-change' property allows an author to inform the UA what kinds of style changes are likely to be made to an element, e.g., as a result of animations or other dynamic effects. This allows the UA to optimize how it handles the element.


CSS Counter Styles Level 3

This module introduces the ‘@counter-style’ rule, which allows authors to define their own custom counter styles for use with CSS list-marker and generated-content counters. It also predefines a set of common counter styles.


Compositing and Blending Level 1

Compositing describes how shapes of different elements are combined into a single image by overlaying, masking, blending, etc. The specification also defines a syntax for using compositing in CSS.


Geometry Interfaces Module Level 1

This specification provides basic geometric interfaces.


CSS Backgrounds and Borders Module Level 3

CSS is a language for describing the rendering of structured documents (such as HTML and XML) on screen, on paper, in speech, etc. This draft contains the features of CSS level 3 relating to borders and backgrounds. It includes and extends the functionality of CSS level 2 [CSS21], which builds on CSS level 1 [CSS1] . The main extensions compared to level 2 are borders consisting of images, boxes with multiple backgrounds, boxes with rounded corners and boxes with shadows.

This module replaces two earlier drafts: CSS3 Backgrounds and CSS3 Border.


CSS Masking Module Level 1

CSS Masking provides two means for partially or fully hiding portions of visual elements: masking and clipping. Masking describes how to use another graphical element or image as a luminance or alpha mask. Clipping describes the visible region of visual elements. This module defines faetures for both SVG and CSS.


CSS Shapes Module Level 1

CSS Shapes control the geometric shapes used for wrapping inline flow content outside an element.


CSS Syntax Module Level 3

This CSS3 module describes the basic structure of CSS style sheets, some of the details of the syntax, and the rules for parsing CSS style sheets. It also describes (in some cases, informatively) how stylesheets can be linked to documents and how those links can be media-dependent. Additional details of the syntax of some parts of CSS described in other modules will be described in those modules. The selectors module has a grammar for selectors. Modules that define properties give the grammar for the values of those properties, in a format described in this document.


CSS Fonts Module Level 3

This CSS3 module describes how font properties are specified and how font resources are loaded dynamically. The contents of this specification are a consolidation of content previously divided into CSS3 Fonts and CSS3 Web Fonts modules.


CSS Text Decoration Module Level 3

This module contains the features of CSS relating to text decoration, such as underlines, text shadows, and emphasis marks.


CSS Conditional Rules Module Level 3

Style rules in CSS can depend on external factors: the output media ('@media'), the capabilities of the user agent ('@supports') and the URI of the document ('@document').


CSS Image Values and Replaced Content Module Level 3

The draft defines how to refer to images and other external objects from within CSS, including fallback images in different formats, special URLs for vector images of color gradients, and different ways to set the size of images and other objects.


CSS Speech Module

CSS (Cascading Style Sheets) is a language for describing the rendering of HTML and XML documents on screen, on paper, in speech, etc. CSS defines aural properties that give control over rendering XML to speech. This draft describes the text to speech properties proposed for CSS level 3. These are designed for match the model described in the Speech Synthesis Markup Language (SSML) Version 1.0 [SSML10]

The CSS3 Speech Module is a community effort and if you would like to help with implementation and driving the specification forward along the W3C Recommendation track, please contact the editors.


CSS Multi-column Layout Module

This module describes multi-column layout in CSS. It builds on the CSS3 Box model module and adds functionality to flow the content of an element into multiple columns.

Last Call Drafts


CSS Font Loading Module Level 3

The CSS Font Loading module describes events and interfaces used for dynamically loading font resources.


CSS Text Module Level 3

This CSS3 module defines properties for text manipulation and specifies their processing model. It covers line breaking, justification and alignment, white space handling, text decoration and text transformation.

Other Working Drafts


Media Queries Level 4

Media Queries allow authors to test and query values or features of the user agent or display device, independent of the document being rendered.


CSS Logical Properties and Values Level 1

CSS Logical Properties and Values Level 1 defines properties that indirectly set certain other CSS properties (including width, margin, float, text-align and page-break) based on the writing mode: left-to-right, right-to-left or top-to-bottom. They are useful in simple, generic style sheets, such as User Agent style sheets, but may also save a few lines in styles for documents with both left-to-right and right-to-left text.


CSS Box Alignment Module Level 3

This module contains the features of CSS relating to the alignment of boxes within their containers in the various CSS box layout models: block layout, table layout, flex layout, and grid layout.


CSS Containment Module Level 1

This CSS module describes the contain property, which indicates that the element’s subtree is independent of the rest of the page. This enables heavy optimizations by user agents when used well.


CSS Image Values and Replaced Content Module Level 4

The specification describes how CSS uses images: external images linked via a URL, sets of fallback images and various built-in color gradients. Images can be resized or cropped.


CSS Fill and Stroke Module Level 3

This module contains the features of CSS relating to filling and stroking text and SVG shapes.


CSS Table Module Level 3

This CSS module defines a two-dimensional grid-based layout system, optimized for tabular data rendering. In the table layout model, each display node is assigned to an intersection between a set of consecutive rows and a set of consecutive columns, themselves generated from the table structure and sized according to their content.


CSS Rhythmic Sizing

This specification allows controlling sizes of CSS objects to be multiple of a unit, for example to produce a consistent vertical typographic rhythm.


CSS Timing Functions Level 1

This CSS module describes a way for authors to define a transformation to be applied to the time of an animation. This can be used to produce animations that mimic physical phenomena such as momentum or to cause the animation to move in discrete steps producing robot-like movement.


Requirements for Chinese Text Layout 中文排版需求

This document summarizes the text composition requirements in the Chinese writing system. One of the goals of the task force is to describe the issues in the Chinese layout requirements, another one is to provide satisfactory equivalent to the current standards (i.e. Unicode), also to promote vendors to implement those relevant features correctly.


CSS Intrinsic & Extrinsic Sizing Module Level 3

This module of CSS defines keywords for the 'width' and 'height' properties to allow a designer to specify that an element should be as small as possible, as large as possible, or as large as possible up to the limit of its containing block. The 'width' and 'height' properties themselves are defined in the CSS Box Model.


CSS Display Module Level 3

The CSS Display Module contains the features of CSS relating to the 'display' property and some other box-generation details.


Timed Text Markup Language 2 (TTML2)

The Timed Text Markup Language is a content type that represents timed text media for the purpose of interchange among authoring systems and for distribution for example as a format to reference from an HTML element. Timed text is textual information that is intrinsically or extrinsically associated with timing information.


CSS Round Display Level 1

CSS Round Display Level 1 describes CSS features to help authors build a Web page suitable for a round display. It extends CSS modules such as Media Queries, CSS Shapes, Borders, and Positioned Layout.


Ethiopic Layout Requirements

This document describes requirements for the layout and presentation of text in languages that use the Ethiopic script when they are used by Web standards and technologies, such as HTML, CSS, Mobile Web, Digital Publications, and Unicode.


Web Animations

This specification defines a model for synchronization and timing of changes to the presentation of a Web page. This specification also defines an application programming interface for interacting with this model and it is expected that further specifications will define declarative means for exposing these features.


CSS Color Module Level 4

This specification describes CSS <color> values and properties for foreground color and group opacity.


CSS Pseudo-Elements Module Level 4

This CSS module defines pseudo-elements, abstract elements that represent portions of the CSS render tree that can be selected and styled.


Worklets Level 1

This specification defines an API for running scripts in stages of the rendering pipeline independent of the main javascript execution environment.


CSS Painting API Level 1

This specification describes an API which allows developers to paint a part of an box in response to geometry / computed style changes with an additional <image> function.


CSS Properties and Values API Level 1

This CSS module defines an API for registering new CSS properties. Properties registered using this API are provided with a parse syntax that defines a type, inheritance behaviour, and an initial value.


CSS Typed OM Level 1

Converting CSSOM value strings into meaningfully typed JavaScript representations and back can incur a significant performance overhead. This specification exposes CSS values as typed JavaScript objects to facilitate their performant manipulation.


CSS Generated Content Module Level 3

This CSS3 Module describes how to insert content in a document.


CSS Overflow Module Level 3

CSS is a language for describing the rendering of structured documents (such as HTML and XML) on screen, on paper, in speech, etc. This module contains the features of CSS relating to new mechanisms of overflow handling in visual media (e.g., screen or paper). In interactive media, it describes features that allow the overflow from a fixed size container to be handled by pagination (displaying one page at a time). It also describes features, applying to all visual media, that allow the contents of an element to be spread across multiple fragments, allowing the contents to flow across multiple regions or to have different styles for different fragments.


CSS Inline Layout Module Level 3

This module describes the positioning in the block progression direction both of elements and text within lines and of the lines themselves. It also describes special features for formatting of first lines and drop caps.


CSS Positioned Layout Module Level 3

CSS Positioned Layout defines the five ways to lay out elements with CSS: four ways from CSS level 2 ('static', 'relative', 'absolute' and 'fixed') and a fifth way, to position elements relative to a page box.


Cascading Style Sheets Level 2 Revision 2 (CSS 2.2) Specification

CSS is a style sheet language that allows authors and users to attach style (e.g., fonts and spacing) to structured documents (e.g., HTML documents and XML applications). CSS 2.2 is the second revision of level 2 of CSS. It corrects a few errors in CSS 2.1.


CSS Device Adaptation Module Level 1

This specification provides a way for an author to specify, in CSS, the size, zoom factor, and orientation of the viewport that is used as the base for the initial containing block.


CSSOM View Module

The APIs introduced by this specification provide authors with a way to inspect and manipulate the view information of a document. This includes getting the position of element layout boxes, obtaining the width of the viewport through script, and also scrolling an element.


CSS Object Model (CSSOM)

CSSOM defines APIs (including generic parsing and serialization rules) for Media Queries, Selectors, and CSS itself.


WebVTT: The Web Video Text Tracks Format

This specification defines WebVTT, the Web Video Text Tracks format. Its main use is for marking up external text track resources in connection with the HTML element. WebVTT files provide captions or subtitles for video content, and also text video descriptions [MAUR], chapters for content navigation, and more generally any form of metadata that is time-aligned with audio or video content.


CSS Text Module Level 4

This module defines properties for text manipulation and specifies their processing model. It covers line breaking, justification and alignment, white space handling, and text transformation.


CSS Basic User Interface Module Level 4

CSS Basic UI Level 4 describes CSS properties and values to style basic user interface elements.


CSS Page Floats

CSS Page Floats describes how to use CSS to place "floats" at the top or bottom of certain areas. This feature has traditionally been used in print publications in which figures and photos are moved to the top or bottom of columns or pages.


Priorities for CSS from the Digital Publishing Interest Group

This document documents CSS features needed by the digital publishing community, as determined by the W3C Digital Publishing Interest Group.


Requirements for Hangul Text Layout and Typography 한국어 텍스트 레이아웃 및 타이포그래피를 위한 요구사항

This document describes requirements for general Korean language/Hangul text layout and typography realized with technologies like CSS, SVG and XSL-FO. The document is mainly based on a project to develop the international standard for Korean text layout. It is similar in intent to the Japanese Layout Requirements WG Note.


Motion Path Module Level 1

The Motion Path module of CSS defines an additional way to define the position and rotation of elements when rendering a document. The position is given by a trajectory and an offset along that trajectory between 0 and 100%. In combination with animations, the offset can also be animated.


CSS Exclusions Module Level 1

The module defines (1) properties to assign a shape (circle or polygon) to CSS boxes, to control the line length more precisely than with margins; (2) properties to define how text in other boxes wraps around such a shaped box; and (3) properties to turn an absolutely positioned box into an exclusion, causing text to wrap around it, too.


Filter Effects Module Level 1

Filter effects are a way of processing an element's rendering before it is displayed in the document. Typically, rendering an element via CSS or SVG can conceptually described as if the element, including its children, are drawn into a buffer (such as a raster image) and then that buffer is composited into the elements parent. Filters apply an effect before the compositing stage. Examples of such effects are blurring, changing color intensity and warping the image.

Although originally designed for use in SVG, filter effects are a set a set of operations to apply on an image buffer and therefore can be applied to nearly any presentational environment, including CSS. They are triggered by a style instruction (the ‘filter’ property). This specification describes filters in a manner that allows them to be used in content styled by CSS, such as HTML and SVG. It also defines a CSS property value function that produces a CSS value.


CSS Regions Module Level 1

The CSS Regions specification defines CSS properties to distribute the content of one element over multiple, disconnected regions, such as the regions defined by CSS Grid Layout.


CSS Line Grid Module Level 1

This module contains CSS features for aligning content to a baseline grid.


CSS Ruby Layout Module Level 1

The set of CSS properties proposed in this document can be used in combination with the ruby elements of HTML to produce the stylistic effects needed to display ruby text appropriately relative to base text.


Non-element Selectors Module Level 1

Non-element Selectors extends Selectors level 4 and allows selecting other kinds of document nodes than elements. This is useful when selectors are used as a general document query language. Non-element selectors are not intended to be used in CSS itself.


CSS Generated Content for Paged Media Module

This module describes features often used in printed publications. In particular, this specification describes how CSS style sheets can express running headers and footers, leaders, cross-references, footnotes, sidenotes, named flows, hyphenation, new counter styles, character substitution, image resolution, page floats, advanced multi-column layout, conditional content, crop and cross marks, bookmarks, CMYK colors, continuation markers, change bars, line numbers, named page lists, and generated lists. Along with two other CSS3 modules – multi-column layout and paged media – this module offers advanced functionality for presenting structured documents on paged media.


SVG Integration

SVG Integration defines how SVG documents must be processed when used in various contexts, such as CSS background images, HTML ‘iframe’ elements, and so on. These requirements include which features are restricted or disabled, such as scripting and animation.


CSS Scoping Module Level 1

This specification defines various scoping/encapsulation mechanisms for CSS, including scoped styles and the @scope rule, Shadow DOM selectors, and page/region-based styling.


CSS Lists and Counters Module Level 3

This CSS level 3 module describes how lists are styled.


CSS Transforms Module Level 1

CSS transforms allows elements styled with CSS to be transformed in two-dimensional or three-dimensional space.


CSS Transitions

CSS Transitions allows property changes in CSS values to occur smoothly over a specified duration.


DOMMatrix interface

This specification defines a DOM interface representing 2D and 3D matrices. It is intended to be used as a common interface by SVG, Canvas and CSS Transforms.


Selectors Level 4

Selectors are patterns that match against elements in a tree. They are a core component of CSS (Cascading Style Sheets), which uses Selectors to bind style properties to elements in a document.


CSS Paged Media Module Level 3

This module describes the page model that partitions a flow into pages. It builds on the Box model module and introduces and defines the page model and paged media. It adds functionality for pagination, page margins, page size and orientation, headers and footers, widows and orphans, and image orientation. Finally it extends generated content to enable page numbering and running headers / footers.


CSS Animations

CSS Animations allow an author to modify CSS property values over time.


CSS basic box model

CSS (Cascading Style Sheets) describes the rendering of documents on various media. When textual documents (e.g., HTML) are laid out on visual media (e.g., screen or print), CSS models the document as a hierarchy of boxes containing words, lines, paragraphs, tables, etc. each with properties such as size, color and font.

This module describes the basic types of boxes, with their padding and margin, and the normal “flow” (i.e., the sequence of blocks of text with margins in-between). It also defines “floating” boxes, but other kinds of layout, such as tables, absolute positioning, ruby annotations, grid layouts, columns and numbered pages, are described by other modules. Also, the layout of text inside each line (including the handling of left-to-right and right-to-left scripts) is defined elsewhere.

Boxes may contain either horizontal or vertical lines of text. Boxes of different orientations may be mixed in one flow. (This is a level 3 feature.)

Obsolete Specifications

These specifications have either been superseded by others, or have been abandoned. They remain available for archival purposes, but are not intended to be used.




This specification defines an API to allow elements to be rendered fullscreen.


Behavioral Extensions to CSS

Behavioral Extensions provide a way to link to binding technologies, such as XBL, from CSS style sheets. This allows bindings to be selected using the CSS cascade, and thus enables bindings to transparently benefit from the user style sheet mechanism, media selection, and alternate style sheets.


CSS Mobile Profile 2.0

This specification defines in general a subset of CSS 2.1 [CSS21] that is to be considered a baseline for interoperability between implementations of CSS on constrained devices (e.g. mobile phones). Its intent is not to produce a profile of CSS incompatible with the complete specification, but rather to ensure that implementations that due to platform limitations cannot support the entire specification implement a common subset that is interoperable not only amongst constrained implementations but also with complete ones. Additionally, this specification aligns itself as much as possible with the OMA Wireless CSS 1.1 [WCSS11] specification. At the same time, OMA is doing alignment work in OMA Wireless CSS 1.2 [WCSS12]. It is aimed at aligning the mandatory compliance items between CSS Mobile Profile 2.0 and OMA Wireless CSS 1.2 [WCSS12].


CSS TV Profile 1.0

This specification defines a subset of Cascading Style Sheets Level 2 and CSS3 Module: Color specifications tailored to the needs and constraints of TV devices.


CSS Presentation Levels Module

Presentation levels are integer values attached to elements in a document. Elements that are below, at, or above a certain threshold can be styled differently. This feature has two compelling use cases. First, slide presentations with transition effects can be described. For example, list items can be progressively revealed by sliding in from the side. Second, outline views of documents, where only the headings to a certain level are visible, can be generated.


CSS3 Hyperlink Presentation Module

CSS (Cascading Style Sheets) is a simple language for describing the presentation of documents. This specification is a module of level 3 of CSS and contains the functionality required to describe the presentation of hyperlink source anchors and the effects of hyperlink activation.


The CSS ‘Reader’ Media Type

'Reader' is a keyword for use in Media Queries [MEDIAQ]. When a Media Query that includes the 'reader' keyword is attached to (a link to) a style sheet, it indicates that that style sheet is designed to be used by a "reader" device (typically a screen reader), that both displays and speaks a document at the same time. It may also display the document and render it in braille at the same time, or do all three.

Media Queries (and thus 'reader') can be used in documents in HTML [HTML401], XML [XML10], SVG [SVG10], CSS [CSS21] and other formats, wherever they link to a style sheet, and potentially also in links to other resources. (But the latter is not treated in this specification.)


CSS Marquee Module Level 3

CSS describes the rendering of documents on various media. When documents (e.g., HTML) are laid out on visual media (e.g., screen or print) and the contents of some element are too large for a given area, CSS allows the designer to specify whether and how the overflow is displayed. One way, available on certain devices, is the “marquee” effect: the content is animated and moves automatically back and forth. This module defines the properties to control that effect.


Selectors API Level 2

The Selectors API specification defines methods for retrieving Element nodes from the DOM by matching against a group of selectors (as used in CSS).


Aural Cascading Style Sheets (ACSS) Specification

This document describes style sheet properties for rendering Web documents as synthesized speech. Using style sheets rather than HTML tag extensions allows the same document to be read with visual, aural, or mulitmodal presentation without cluttering up the document or having to produce three (or more) separate parallel documents - which has been shown to result in consistency and update problems. This approach provides greatly improved document accessibility for visually disabled people (the information is better presented and is just as up-to-date as the visual version) without requiring compromises in the visual design of the document.


Positioning HTML Elements with Cascading Style Sheets

The HyperText Markup Language (HTML) is a simple markup language used to create hypertext documents that are portable from one platform to another. HTML documents are SGML documents with generic semantics that are appropriate for representing information from a wide range of applications. CSS (Cascading Style Sheets) is a style sheets language that can be applied to HTML to control the style of a document: which fonts and colors to use, how much white space to insert, etc. The following specification extends CSS to support the positioning and visibility of HTML elements in three-dimensional space. Familiarity with both CSS1 and HTML 3.2 are assumed.


CSS Printing Extensions

This specification describes a set of extensions to Cascading Style Sheets (CSS) to better support printing from the Web. These extensions let style sheets express page breaks, page boxes, and media dependencies. Also, a way to point to an alternate print document is described. This is a first pass at a rather formidable problem, but one which can yield good results in the near term.