CSS documentation status

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Pages No tags Needs* tags Missing tags Editorial reviews Technical reviews Outdated pages Dev-doc-needed bugs Documentation requests Missing pages
735 5 (1%) 315 (43%) 0 (0%) 5 (1%) 97 (14%) 29 (4%) 96 (14%) 33 (5%) 26 (4%)

See also localization status of this section.

No tags

Found 5 pages. Learn more about how to tag pages.

Needs* tags

Found 315 pages. Learn more about how to deal with meta-tags.

Editorial reviews

Found 5 pages. Learn more about how to do an editorial review.

Technical reviews

Found 97 pages. Learn more about how to do a technical review.

Outdated pages

Found 29 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 Outdated pages can have problems with both content and format.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 96 bugs. Learn more about how to resolve a dev-doc-needed bug.

Bug Summary Release
1258626 Implement mask-repeat: [space | round] mozilla49
1266268 [css-grid] Implement <percentage> for grid gap properties mozilla49
955857 accept the overflow-wrap property mozilla49
1228280 (mask-image) Support multiple SVG mask elements as mask images mozilla49
590468 Reduce size of chrome document layer due to status bar ---
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" ---
1110460 Support interpolate of clip-path basic shapes in CSS animations and transitions ---
426447 hasFeature broken for SVG 1.1 style SVG detection - regression. ---
1259889 Consider adding an internal-only syntax for @supports to detect pref mozilla48
1228354 (mask-image) Support 'luminance' and 'match-source' values for 'mask-mode' 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
1258657 Update the default style of summary element to match the html spec mozilla48
1260366 first-letter doesn't apply on dash [maybe another punctuation symbols] mozilla48
1241750 Enable <details> and <summary> on Nightly/Aurora mozilla48
1250342 rename text-align(/-last): true to unsafe mozilla47
1218706 Make unicode-bidi: isolate the default for elements with a dir attribute mozilla47
1251999 [css-grid] Update <fixed-size> parsing to the latest spec mozilla47
686281 Implement CSS Mask Image properties (mask, mask-image, etc.) mozilla47
1213126 Enable layout.css.prefixes.webkit by default (though this was later restricted to non-release builds, in bug 1238827) mozilla46
1230478 [css-grid][css-align]Rename 'true' to 'unsafe' mozilla46
1239128 Implement LinkStyle for SVGStyleElement interface mozilla46
1157064 experimental implementation of font-display CSS @font-face descriptor mozilla46
1230207 [css-grid][css-flexbox] Implement grid/flex layout for <fieldset> mozilla46
1118820 [css-grid] Implement auto-fill, auto-fit in the repeat() function mozilla46
1233106 implement changes to css-align property computation mozilla46
1176782 [css-grid][css-align] Implement full support for the CSS Box Alignment spec in the style system. mozilla45
1224424 mask-mode must not have a value called 'auto' mozilla45
1221677 [css-grid] Put the 'subgrid' support behind a pref, disabled by default mozilla45
1000592 Enable CSS Grid by default in non-release channels mozilla45
1215484 Figure out how high contrast / "ignore author colors" should apply to SVGs mozilla44
920734 support window.orientation and orientationchange event mozilla44
1126230 Use top layer for Fullscreen API mozilla44
1149381 enable the preference for the CSS Font Loading API in release builds mozilla41
1152033 expose CSS tokenizer to javascript 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
1072101 implement the remaining Set-like API of FontFaceSet 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
1045754 Implement alternative to CSSOM-View scroll-behavior Element.scrollTop and Element.scrollLeft extensions mozilla36
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
1087559 Enable CSSOM-View scroll behavior DOM method extensions by default (Except for Fennec) mozilla36
1022818 Implement CSSOM-View smooth scrolling DOM Methods mozilla34
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
1041951 convert font-variant to a shorthand and parse font-variant subproperty values mozilla34
1035106 Add new APIs to DOMUtils: colorToRGBA, IsValidCSSColor & cssPropertyIsValid mozilla33
966166 Implement @counter-style rule mozilla33
1006595 Add domUtils.GetCSSSubPropertiesForProperty, getCSSPropertyIsShorthand, CSSPropertySupportsType (Color, Gradient etc.) 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
850805 Implement DOMPoint (aka WebKitPoint) mozilla31
957833 ship CSS Variables (that is, enable the preference) mozilla31
917755 Implement Node.getBoxQuads mozilla31
983528 enable paint-order property by default 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
956513 SVG text is drawn with wrong position 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
773296 implement CSS3 variables mozilla29
947728 Provide a way for content to hide <input type=number>'s spinner mozilla28
939784 Provide a notification when the applicable state of a style sheet changes mozilla28
929991 Implement 'true' alignment for text-align mozilla27
835048 Figure out if SVGElement.ownerSVGElement should throw mozilla26
798843 change value names for -moz-objectFill to context-fill etc., and put them behind opentype SVG pref mozilla26
879659 implement <marker orient="auto-start-reverse"> from SVG 2 mozilla25
887741 Allow CSS at-rules in declaration lists mozilla25
569722 Firefox SVG support does not implement the textLength and lengthAdjust attribute functionality of <text> elements mozilla25
453650 mechanism for tracking reflows in debugger mozilla24
771551 Add CSS Media Query media feature for device hardware buttons 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
619964 Implement FillPaint and StrokePaint filter sources mozilla17
774122 limit CSS parser hashless-color and unitless-length quirks to only the properties that need them mozilla17
512525 Implement the <view> element mozilla15
512514 Implement hyperlink targeting of animation elements mozilla15
759124 Implement useCurrentView mozilla15
528332 Feature Request: Implement non-scaling-stroke 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 33 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
475817 Better documentation needed for syntax of Mozilla CSS extensions using properties
819654 Convert all samples of the CSS Reference to Live Samples
819657 Convert all samples of CSS tutorials to Live Samples
819658 Translations of CSS Reference must use updated Live Samples
819661 Translations of CSS Tutorials must use updated Live Samples
848308 We need MDC to better document the styling of form controls using pseudo elements
873837 Update "Scaling background images" to cover background-image and background-size
885664 MARGIN-TOP : Confusing explanation about the relative area when using percentage
904680 Missing Documentation (dead links) for 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 in sub pages
1133414 Add page for deprecated media types and groups
1180569 https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Getting_Started/Selectors
1189440 Consider using shepherd (bikeshed tool) in the context of CSSData
1229544 flex-grow fails to describe how it modifies layout
1230720 [meta] Document non-standard <input>-related CSS pseudo-elements & pseudo-classes
1230724 Document ::-ms-check pseudo-element
1230725 Document ::-webkit-file-upload-button pseudo-element
1231610 Document ::-webkit-inner-spin-button and ::-webkit-outer-spin-button pseudo-elements
1231850 Document non-standard pseudo-elements of HTML5 <progress> element
1238322 Document WebVTT's :current, :past, :future CSS pseudo-classes
1240279 Document Mozilla-specific pseudo-classes and pseudo-elements for the <meter> element
1247845 The first two examples for CSS transform don't work for me
1252805 text-transform does nothing with ::first-line pseudo-element
1252853 Collapsing margins and flexbox
1252892 @page/size documentation missing (link from @page)
1255315 Can't find the meaning of "display: -moz-box" style attribute
1256335 The description for Max-Height percentage is ambiguous
1262401 Page Not Found: https://developer.mozilla.org/en-US/docs/Web/CSS/@page/size
1263828 Some CSS properties appear twice in the sidebar
1267064 Update all CSS2 links to CSS 2.2
1276323 min-height, min-width default should be 'auto', not 0

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
bn-BD 735 12 (1%) 3 (25%)
cs 677 4 (0%) 0 (0%)
de 735 402 (54%) 194 (48%)
es 735 268 (36%) 131 (48%)
fa 735 4 (0%) 0 (0%)
fr 735 590 (80%) 487 (82%)
it 735 34 (4%) 11 (32%)
ja 735 366 (49%) 144 (39%)
ko 735 80 (10%) 40 (50%)
nl 677 5 (0%) 2 (40%)
pl 735 138 (18%) 20 (14%)
pt-BR 735 84 (11%) 27 (32%)
pt-PT 677 64 (9%) 12 (18%)
ru 732 129 (17%) 71 (55%)
tr 677 6 (0%) 1 (16%)
zh-CN 677 244 (36%) 124 (50%)
zh-TW 677 27 (3%) 12 (44%)

Missing pages

Learn more about how to document a CSS property.

Missing standard CSS entities implemented in Gecko


Tagging standard

  • Every page should have the tag "CSS".
  • CSS properties belonging to a group 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 dev-mdc mailing-list:

Document Tags and Contributors

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