Platform status

"display: contents" allows you to control the box generation of an element. The element with "display: contents" won't generate any box, but its children and pseudo-elements will still do it as normal. It's like the element has been replaced by its children and pseudo-elements.

Provides a way to blend an HTML or SVG element with its backdrop

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

Support the attr() function as a component value in properties applied to an element. Currently, attr() is only supported in the content property applied to pseudo-elements.

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

The :focus-within pseudo-class applies to elements for which the :focus pseudo class applies. An element also matches :focus-within if one of its descendants in the flat tree (including non-element nodes, such as text nodes) matches the conditions for matching :focus.

Roadmap Priority: High — We intend to begin development soon.

Define arbitrary shapes inside and around which inline content can flow.

Roadmap Priority: Medium — Development is likely for a future release.

The relational pseudo-class, :has(), is a functional pseudo-class taking a relative selector list as an argument. Similar to jQuery’s :has() selector.

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

CSS properties for aligning boxes within their container. Allows for true vertical centering among other features.

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

CSS properties that control the position and size of replaced content within the content box

Roadmap Priority: Medium — Development is likely for a future release.

Adds a will-change CSS property, that can be used to signal that a particular property is likely to be changed in the future, or that an element's content is likely to change.

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

Extends the CSS sizing properties with keywords that represent content-based "intrinsic" sizes and context-based "extrinsic" sizes, allowing CSS to more easily describe boxes that fit their content or fit into a particular layout context.

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

Specifies a gradient where the color stops are placed around the circumference of a circle.

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

Provides a hint to the browser on which scaling algorithm should be used.

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

Motion paths allow authors to animate any graphical object along an author specified path.

Roadmap Priority: Medium — Development is likely for a future release.

The all property is a shorthand that resets all CSS properties except direction and unicode-bidi

Roadmap Priority: Medium — Development is likely for a future release.

Enables responsive images in CSS by specifiying multiple resolutions of an image that the browser can select from for the given situation.

Roadmap Priority: Medium — Development is likely for a future release.

Adds an optional argument to existing scroll APIs that specifies whether scrolling should be smooth. Also adds a CSS property for this.

Boolean attribute for the <style> element (<style scoped>). When present, its styles only apply to the parent element.

The tab-size property sets the size used to render tab characters in situations where white space is preserved

Roadmap Priority: Medium — Development is likely for a future release.

Introduces logical properties and values that provide the author with the ability to control layout through logical, rather than physical, direction and dimension mappings.

Roadmap Priority: High — We intend to begin development soon.

Applies while an element matches the :focus pseudo-class and the user agent (browser, etc) determines via heuristics that the focus should be made evident on the element.

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

The :scope pseudo-class represents any element that is in the contextual reference element set.

Roadmap Priority: Medium — Development is likely for a future release.

Filter effects are a way of processing an element’s rendering before it is displayed in the document.

CSS properties helpful for printed publication.

Allows multiple instances of fonts to be defined by interpolating glyph outlines along different axis.

Unprefixed version: Microsoft Edge build 17074+

Allows authors to utilize longhand properties of font-variant-caps, font-variant-ligatures, font-variant-numeric, font-variant-alternates, font-variant-east-asian, font-variant-position for font selection and adjustments rather than utilizing lower level props such as font-feature-settings.

Roadmap Priority: Medium — Development is likely for a future release.

The -webkit-text-stroke property sets the stroke width and color of an element’s text.

Allows the author to set the size and depth at which it sinks into the surrounding text.

Roadmap Priority: Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.

:in-range and :out-of-range pseudo-classes to match elements that are candidates for constraint validation, have range limitations, and are/are not suffering from underflow or overflow.

Unprefixed version: Microsoft Edge build 10547+

:read-only and :read-write pseudo-classes to match elements which are considered user-alterable for the purposes of Selectors.

Unprefixed version: Microsoft Edge build 10547+

Method of allowing calculated values for length units, i.e. width: calc(100% - 3em)

Unprefixed version: IE 9+, Microsoft Edge build 10240+

The @viewport rule, in combination with media queries, enabled web developers to optimize the layout of sites and apps for different devices with minimal effort. It generalizes the viewport meta tag to CSS, while being much simpler to understand and without the quirks that exists with the meta tag.

Preview in: by enabling in about:flags

Introduces cascading variables as a new primitive value type that is accepted by all CSS properties, and custom properties for defining them.

Unprefixed version: Microsoft Edge build 15063+

Define areas inline content should avoid, and how inline content should wrap around them.

Prefixed version: IE 10+, Microsoft Edge build 10240+

Apply filter effects to arbitrary DOM elements.

Unprefixed version: Microsoft Edge build 10586+

A CSS box model optimized for user interface design. The children of a flex container can be laid out in any direction and can "flex" their sizes to fill unused space and avoid overflowing the parent.

Prefixed version: IE 10+, Microsoft Edge build 10240+

Unprefixed version: IE 11, Microsoft Edge build 10240+

Gradients provide a method to, over a customizable amount of space, transition from one color to another.

Unprefixed version: IE 10+, Microsoft Edge build 10240+

A two-dimensional grid-based layout system, optimized for user interface design.

Prefixed version: IE 10+, Microsoft Edge build 10240+

Unprefixed version: Microsoft Edge build 16299+

Allows hiding of portions of a visible elements.

Unprefixed version: Microsoft Edge build 17763+

Allows to query the device pixel count per CSS unit

Unprefixed version: IE 9+, Microsoft Edge build 10240+

Augments existing CSS 3d transforms by facilitating the construction of complex 3d scenes.

Unprefixed version: Microsoft Edge build 10240+

Specifies the blending mode used for each background layer

Preview in: Windows Insider Preview Build 17763+ by enabling in about:flags

Increases interoperability with the web by relaxing domain and licensing metadata restrictions for EOT, WOFF, and TrueType fonts. Development work for IE is currently for Windows Phone only.

Allows content to be flowed into multiple columns with a gap and a rule between them using CSS.

Unprefixed version: IE 10+, Microsoft Edge build 10240+

position: sticky is a new way to position elements and is conceptually similar to position: fixed. The difference is that a stickily positioned element behaves like position: relative within its parent, until a given offset threshold is met.

Unprefixed version: Microsoft Edge build 16299+