We're looking for a user researcher to understand the needs of developers and designers. Is this you or someone you know? Check out the post: https://mzl.la/2IGzdXS

This page tries to track ongoing documentation work in the MDN CSS section. Feel free to contribute!


Pages No tags Needs* tags Missing tags Editorial reviews Technical reviews Outdated pages Dev-doc-needed bugs Documentation requests Missing pages
884 16 (2%) 204 (24%) 0 (0%) 64 (8%) 146 (17%) 7 (1%) 120 (14%) 48 (6%) 26 (3%)

See also localization status of this section.

No tags

Found 16 pages. Learn more about how to tag pages.

Needs* tags

Found 204 pages. Learn more about how to deal with meta-tags.

Editorial reviews

Found 64 pages. Learn more about how to do an editorial review.

Technical reviews

Found 146 pages. Learn more about how to do a technical review.

Outdated pages

Found 7 pages. These pages haven't been updated in over a year. Outdated pages can have problems with both content and format. Look at these pages and consider: Is this page talking about the Web of today? Does it look consistent with newer pages in this topic area? If not, make any needed changes.

Dev-doc-needed bugs

Found 120 bugs. Learn more about how to resolve a dev-doc-needed bug.

Bug Summary Release
509958 Remove the -moz prefix from ::selection mozilla62
1460655 Support 'x' as a resolution unit. mozilla62
1408301 unship CSSStyleDeclaration::getPropertyCSSValue mozilla62
1459871 Remove other getPropertyCssValue-related interfaces. mozilla62
1256575 Support calc() in media queries ---
736431 Inline <svg> is given the CSS default height of 150px when the height is not explicitly specified ---
912434 text-overflow: ellipsis does not work, when specified on an element that has "display: flex" ---
426447 hasFeature broken for SVG 1.1 style SVG detection - regression. ---
1266283 Implement CSS4 descendant combinator >> ---
590468 Reduce size of chrome document layer due to status bar ---
1352756 Implement color-mod() from CSS Color Module Level 4 ---
1436061 Update font-{style,weight,stretch} @font-face descriptors to accept additional values per CSS Fonts 4 ---
1117572 Implement >>> Selecting Through Shadows Selector for access into shadow root ---
1282821 [css-flexbox] Flex items that are sized to content should use max-content size (not fit-content) ---
1348208 Consider removing -moz-force-broken-image-icon property ---
1055385 implement font-variant descriptor for @font-face rules ---
1436048 Change font-weight, font-stretch and font-style to use user-defined types mozilla61
1446470 Parse @-moz-document url-prefix() on content. mozilla61
1453148 Make `overflow` take two values mozilla61
1346988 stylo: Consider parallelizing CSS parsing mozilla61
1105111 Implement "flex-basis: content" keyword for flexbox mozilla61
1452143 Consider disabling CSS error reporting by default mozilla61
1265342 Implement 'shape-margin' for all shapes except polygon mozilla61
1398482 [css-grid] Drop the "grid-" prefix from the grid-gap, grid-row-gap, and grid-column-gap properties mozilla61
1422245 Toggle the pref to disable @-moz-document in content pages on release mozilla61
1427419 convert inIDOMUtils to Web IDL mozilla59
265894 Support SVG CSS selector matching rules for <svg:use> mozilla56
1319137 (intersection-observer) Add isIntersecting property to IntersectionObserverEntry mozilla55
1243846 Implement Intersection Observer API mozilla55
1340309 [css-align] Implement the updated spec language for interactions between "align-items" & "align-self", "justify-items" & "justify-self" mozilla54
418833 can't define the style of input when the type is set to "checkbox" or "radio" with CSS mozilla53
1216893 Add pref to optionally disable SVG (Tor 12827) mozilla53
1151204 [css-grid] Implement Grid container Baselines mozilla52
1259345 Let layout.css.prefixes.webkit ride the trains mozilla49
1260366 first-letter doesn't apply on dash [maybe another punctuation symbols] mozilla48
1241750 Enable <details> and <summary> on Nightly/Aurora mozilla48
1258657 Update the default style of summary element to match the html spec mozilla48
1259889 Consider adding an internal-only syntax for @supports to detect pref mozilla48
1243734 Have a pref to enable/ disable all new mask CSS properties added in bug 686281 mozilla48
1209273 implement the 'color-adjust' CSS property to allow pages to opt in to printing background colors and images (-webkit-print-color-adjust) mozilla48
1218706 Make unicode-bidi: isolate the default for elements with a dir attribute mozilla47
1236979 Send 'webkitTransitionEnd', 'webkitAnimationEnd' etc. events instead of their standard equivalents, if listeners only exist for prefixed event name mozilla47
1251999 [css-grid] Update <fixed-size> parsing to the latest spec mozilla47
1250342 rename text-align(/-last): true to unsafe mozilla47
1118820 [css-grid] Implement auto-fill, auto-fit in the repeat() function mozilla46
1230478 [css-grid][css-align]Rename 'true' to 'unsafe' mozilla46
1213126 Enable layout.css.prefixes.webkit by default (though this was later restricted to non-release builds, in bug 1238827) mozilla46
1230207 [css-grid][css-flexbox] Implement grid/flex layout for <fieldset> mozilla46
1233106 implement changes to css-align property computation mozilla46
1239128 Implement LinkStyle for SVGStyleElement interface mozilla46
1157064 experimental implementation of font-display CSS @font-face descriptor mozilla46
1224424 mask-mode must not have a value called 'auto' mozilla45
1176782 [css-grid][css-align] Implement full support for the CSS Box Alignment spec in the style system. mozilla45
1000592 Enable CSS Grid by default in non-release channels mozilla45
1221677 [css-grid] Put the 'subgrid' support behind a pref, disabled by default mozilla45
1151214 [css-grid] Implement align-content and justify-content mozilla45
1215484 Figure out how high contrast / "ignore author colors" should apply to SVGs mozilla44
1126230 Use top layer for Fullscreen API mozilla44
920734 support window.orientation and orientationchange event mozilla44
1149381 enable the preference for the CSS Font Loading API in release builds mozilla41
1152033 expose CSS tokenizer to javascript mozilla40
1072101 implement the remaining Set-like API of FontFaceSet mozilla40
1028716 update values of -moz-orient for <progress> and <meter> to remove 'auto', and add 'inline' (new initial value) and 'block' values with writing-mode support mozilla40
1125455 rewrite cascading of CSS Transitions and Animations to match current spec mozilla39
960465 rewrite starting of CSS transitions to match current spec mozilla38
649142 support logical box properties (-start/-end) without hidden longhand properties mozilla38
1107584 ship <marker orient="auto-start-reverse"> mozilla37
886390 Assigning to innerHTML on an SVG element should create elements in the SVG namespace mozilla36
1074056 Add support for interpolation hints to CSS gradients mozilla36
1087562 Enable CSSOM-View scroll behavior CSS property by default (Except for Fennec) mozilla36
1045754 Implement alternative to CSSOM-View scroll-behavior Element.scrollTop and Element.scrollLeft extensions mozilla36
1087559 Enable CSSOM-View scroll behavior DOM method extensions by default (Except for Fennec) mozilla36
975744 enable font-variant-* / font-feature in release by default mozilla34
1015474 Update min-width:auto/min-height:auto support to match updated flexbox spec language mozilla34
1022818 Implement CSSOM-View smooth scrolling DOM Methods mozilla34
1041951 convert font-variant to a shorthand and parse font-variant subproperty values mozilla34
1006595 Add domUtils.GetCSSSubPropertiesForProperty, getCSSPropertyIsShorthand, CSSPropertySupportsType (Color, Gradient etc.) mozilla33
1024707 Add API to register style sheets but without loading them mozilla33
1035106 Add new APIs to DOMUtils: colorToRGBA, IsValidCSSColor & cssPropertyIsValid mozilla33
966166 Implement @counter-style rule mozilla33
999964 Implementation Proposal for 'clipped' option of SVG 2 getBBox method. mozilla32
1008455 Avoid loading the xul.css UA style sheet when possible mozilla32
918189 Implement Node.convertPoint/Rect/QuadFromNode mozilla31
957833 ship CSS Variables (that is, enable the preference) mozilla31
850805 Implement DOMPoint (aka WebKitPoint) mozilla31
983528 enable paint-order property by default mozilla31
917755 Implement Node.getBoxQuads mozilla31
964200 Implement Filter Effects Module feDropShadow filter mozilla30
966992 Implement overflow-clip-box: content-box mozilla30
944291 Cropping of element with css transform + animation applied, starting in Firefox 25 mozilla29
773296 implement CSS3 variables mozilla29
943249 The overflow property on an <iframe> is propagated to the viewport of the inner document (unlike other UAs) mozilla29
946920 Moving a child element outside of a parent element while moving the parent element, both using transform: translate(), will cause the child element to disappear mozilla29
956513 SVG text is drawn with wrong position mozilla29
939784 Provide a notification when the applicable state of a style sheet changes mozilla28
947728 Provide a way for content to hide <input type=number>'s spinner mozilla28
798843 change value names for -moz-objectFill to context-fill etc., and put them behind opentype SVG pref mozilla26
835048 Figure out if SVGElement.ownerSVGElement should throw mozilla26
569722 Firefox SVG support does not implement the textLength and lengthAdjust attribute functionality of <text> elements mozilla25
879659 implement <marker orient="auto-start-reverse"> from SVG 2 mozilla25
887741 Allow CSS at-rules in declaration lists mozilla25
771551 Add CSS Media Query media feature for device hardware buttons mozilla24
453650 mechanism for tracking reflows in debugger mozilla24
549861 implement parsing of font feature properties mozilla24
851379 Make flex item vertical margin/padding resolve percentages against height of the flex container mozilla23
785606 Consider implementing viewBox="none" from SVG 1.2 Tiny mozilla22
827799 Visually Hidden HTML 5 technique does not hide the caption in a table mozilla21
804944 add preferences for sets of CSS prefixed properties mozilla19
745025 Implement CanvasElement.mozPrintCallback mozilla18
732209 Allow access to the rules of cross-origin sheets that have undergone a CORS check mozilla18
737003 Offer a way to apply user agent stylesheet on a given document mozilla18
774122 limit CSS parser hashless-color and unitless-length quirks to only the properties that need them mozilla17
619964 Implement FillPaint and StrokePaint filter sources mozilla17
528332 Feature Request: Implement non-scaling-stroke mozilla15
759124 Implement useCurrentView mozilla15
512514 Implement hyperlink targeting of animation elements mozilla15
721920 Honor the 'lang' attribute on SVG as we do in HTML mozilla13
665597 Include margin calculations in FinishAndStoreOverflow mozilla12
589640 (ietestcenter) HTML5 Foreign Content 14/24: <altGlyphDef> is not an SVGElement mozilla11
611099 remove handling of percentages as intrinsic widths/heights (SVG height="100%" width="100%" defaults) mozilla11

Browse as bug list.

Documentation requests

Found 48 bugs. Documentation request bugs can contain various kinds work related to MDN pages. Read through the bug and ask questions in the bug if in doubt.

Bug Summary
848308 We need MDC to better document the styling of form controls using pseudo elements
904680 Document CSS Inline Formatting Context
963742 @font-face example font Bitstream Vera Bold is broken in IE9-10 (tested) possibly others.
1071549 Explanation about multiple selectors (comma)
1120964 Split display property into subpages
1133414 Add page for deprecated media types and groups
1180569 HTML of example output in selectors guide does not reflect the code
1229544 flex-grow fails to describe how it modifies layout
1230720 [meta] Document non-standard <input>-related CSS pseudo-elements & pseudo-classes
1238322 Document WebVTT's :current, :past, :future CSS pseudo-classes
1240279 Document Mozilla-specific pseudo-classes and pseudo-elements for the <meter> element
1252853 Collapsing margins and flexbox
1255315 Can't find the meaning of "display: -moz-box" style attribute
1256335 The description for Max-Height percentage is ambiguous
1267064 Update all CSS2 links to CSS 2.2
1276323 min-height, min-width default should be 'auto', not 0
1276893 Group items in CSS reference by category
1283378 Describe CSS type combinations of percentages
1288492 Broken links on webkit-inner-spin-button page
1291329 A Twitter follower brought up that CSS properties are called "variables" in our documentation.
1307698 The line-height documentation needs to explain how to use it in a font shorthand
1312712 Split filter functions out into their own pages
1322374 documentation for -webkit-line-clamp
1330580 Update 3D transform properties and functions to refer to CSS Transforms Level 2
1335106 Documentation for the CSS Box Alignment properties
1337867 Color picker tool, lumilance is not updated when entering a hex color
1340159 Rename <br-style> to <line-style> in border-style page
1348612 position:sticky compatibility Opera
1350383 Update `justify-all` on "text-align" page
1352013 Merge '-moz-appearance' info into 'appearance'
1357747 No visual difference in text-rendering examples
1367282 Style attribute vs style element specificity distinction
1367534 For the text-justify style, page says that "distribute" is deprected and that it's the same as inter-word. I don't think it's deprecated and it is not inter-word.
1371361 The Marvelous Dogmas of Nobody
1387588 Example doesn't work because the corresponding .ttf is running into CORS
1404579 Please add a page for CSS new min() and max() functions
1425126 font-variant-numeric: ordinal not working on linux
1427737 Request for clarification of document on Display property
1428478 Document <an-plus-b> CSS syntax
1431288 Lack of clarity in Computed Value
1437901 Add :focus-visible (former :focus-ring)
1439959 Document the :target-within pseudo-class
1442051 Add glossary entry for the term "intrinsic size"
1443884 scroll-snap-type documentation is out of date
1450141 Add glossary entries for the terms "device pixels" and "CSS pixels"
1456323 Document color-adjust
1458422 Update "position sticky" information
1459415 Syntax is not documented for CSS Pseudo class :matches(:any())

Browse as bug list.


Please help us to localize this documentation into different languages. Read more about how to translate.

Language Pages Translated Translations up to date
af 806 0 (0%) 0 (0%)
bn-BD 806 13 (1%) 0 (0%)
cs 806 4 (0%) 0 (0%)
de 806 407 (50%) 6 (1%)
es 806 424 (52%) 15 (3%)
fa 806 6 (0%) 0 (0%)
fr 884 863 (97%) 819 (94%)
it 806 42 (5%) 1 (2%)
ja 884 493 (55%) 244 (49%)
kab 806 2 (0%) 0 (0%)
ko 845 148 (17%) 6 (4%)
nl 806 17 (2%) 1 (5%)
pl 806 148 (18%) 1 (0%)
pt-BR 806 149 (18%) 12 (8%)
pt-PT 806 69 (8%) 1 (1%)
ro 806 5 (0%) 1 (20%)
ru 806 202 (25%) 23 (11%)
tr 806 15 (1%) 2 (13%)
zh-CN 806 388 (48%) 48 (12%)
zh-TW 806 53 (6%) 3 (5%)

Missing pages

Learn more about how to document a CSS property.

Missing standard CSS entities implemented in Gecko


Tagging standards

  • Every page should have the tag "CSS".
  • CSS properties belonging to a group should have the tag of that group, e.g., "CSS Flexible Boxes".


Ideas for future projects or things the ideal CSS documentation should have:

  • Compatibility summary list
  • CSS variables
  • CSS to style forms (non-standard, including Chrome and IE specific styling)
  • Better CSS flexbox documentation


These macros are maintained and actively used in the MDN CSS area. If you want to create and use a new macro, please talk to MDN admins and the CSS topic driver.

Help the 'CSS' documentation project…
Topic driver : Jean-Yves Perrier (IRC nickname: teoli)
Look at the current status of the 'CSS' documentation.
Don't hesitate to contact us on #mdn or on the MDN discourse group/list:

Document Tags and Contributors

Contributors to this page: mfluehr, Sebastianz, fscholz, TylerH, jswisher, teoli
Last updated by: mfluehr,