CSS properties

Usable only in properties that accept the value type. The consuming property determines the percentage basis. Physical units use 96 CSS px/in.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus and is not a standard property.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus and is not a standard property.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus and is not a standard property.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus and is not a standard property.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus and is not a standard property.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus and is not a standard property.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus. Lengths use only the strtof prefix and must be greater than zero; general length units and calc conversion are not implemented.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus. Lengths use only the strtof prefix and must be greater than zero; general length units and calc conversion are not implemented.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus and is not a standard property.

Read from the select element's computed customProperties to override PopupTheme; affects only KUI dropdown menus and is not a standard property.

Overrides TooltipTheme using inherited variables from the tooltip anchor, or html when there is no anchor; affects only KUI tooltips.

Overrides TooltipTheme using inherited variables from the tooltip anchor, or html when there is no anchor; affects only KUI tooltips.

Overrides TooltipTheme using inherited variables from the tooltip anchor, or html when there is no anchor; affects only KUI tooltips.

Reads inherited variables from the tooltip anchor, or html when there is no anchor; affects only PopupManager tooltips. Lengths use the strtof prefix, may be zero, and do not evaluate em, %, or calc conversions.

Consumed only by hit testing for frameless Windows windows; macOS and Linux currently have no corresponding implementation.

overlay does not reserve scrollbar width; auto reserves space. This is a KUI-specific property. KUI extension: overlay scrollbars cover content; otherwise scrollbars occupy layout space.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

Consumed only by hit testing for frameless Windows windows; macOS and Linux currently have no corresponding implementation.

Only none changes the native control painting. Other compatibility keywords retain their computed values but are painted as auto; they do not switch to the named appearance or provide a dedicated base-select UI.

text uses glyph and decoration masks. The prefixed name is an alias for the same path.

Used only by compatibility boxes authored with display:-webkit-box or display:-webkit-inline-box. Its cross-axis value is independent of modern align-items, and its items ignore modern align-self. Invalid values preserve the previous value.

The corresponding case in style_apply_misc returns true unconditionally without writing any style field. Registration, successful parsing, or inherit tests do not establish that reverse layout is implemented.

Only stores a vertical/block-axis boolean for legacy clamping. This is not a complete implementation of the old WebKit box layout model.

Shares the empty implementation branch with -webkit-box-direction and returns true unconditionally. Does not change justify-content or any other main-axis distribution field.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

Like image-set(), it is collapsed only in the background selection path, with a fixed 1dppx target; resources are not reselected dynamically for DPR changes. Parsing happens before the entire background value is split into layers, and a source is selected only if the whole value starts with image-set. It does not recursively expand image-set within arbitrary layers; trailing shorthand and multilayer text are also limited.

Legacy mode requires an authored display:-webkit-box or -webkit-inline-box together with -webkit-box-orient:vertical/block-axis. Uses an automatic ellipsis marker.

The basic shorthand only extracts the image source; it does not expand the complete mask grammar.

The image path is available. Splitting at bare commas limits gradients and data URIs containing commas. The backend only handles linear/radial gradients; all images are scaled to the box.

Storage only: applyMask currently does not read size/position/repeat/origin/clip/composite, so these values cannot be claimed to produce an effect.

Storage only: applyMask currently does not read size/position/repeat/origin/clip/composite, so these values cannot be claimed to produce an effect.

Storage only: applyMask currently does not read size/position/repeat/origin/clip/composite, so these values cannot be claimed to produce an effect.

Stores a separate optional color; actual body text drawing uses usedTextFillColor.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

The built-in registry, logical mapping, declaration expansion, and apply dispatch currently provide no implementation path that uses this property. Its appearance in examples, storage in CSSOM, or support for the corresponding standard property does not prove this name takes effect.

Generates a content box after the element's content; supports the same generated-content subset as before.

Dedicated top-layer backdrop painting; depends on dialog/top-layer support.

Generates a content box before the element's content; supported content types, box properties, and layout properties are limited by the current generated-content implementation.

Recognized and bucketed; selector(::column) returns true. No supported properties consume it, and it produces no CSS styling or painting.

The pseudo-element wrapping details content, including its before/after pseudo-elements. Subject to the details open state and special box-tree constraints.

Uses the first-letter text/floating-box path. Applies only to the first letter of eligible block containers.

Uses a dedicated first-line text styling path. Does not provide arbitrary property support or all complex fragmentation behavior.

Has an independent marker cascade that consumes content, fonts, color, letter-spacing and word-spacing. Does not accept arbitrary normal-box properties.

Dedicated measurement and painting styles for the select control icon. Does not provide uniform customization of all input pickers.

The control paints the placeholder text. Arbitrary box properties do not all take effect.

Selection painting uses dedicated parsed results, mainly color, background-color and text-shadow. Does not implement the full highlight inheritance standard.

Matches the activeElement ancestor chain, including the element itself and its ancestors; a forced pseudo state is also available.

An a or area element with href.

No matchPseudoClass branch; unknown pseudo-classes return false.

HTMLInputElement uses the live isChecked() state; other elements are checked only for a checked attribute. Unified option:selected behavior is not implemented.

Matches button and input elements with type=submit or no type. The complete semantics for a form's first default submit control and default option are not implemented.

No matchPseudoClass branch; unknown pseudo-classes return false.

Computed from the HTML dir attribute, ancestors, dir=auto, and the bdi first-strong rule, rather than CSS direction; tel, url, and email use LTR.

Checks only for the presence of the disabled attribute; inherited disabled states from fieldset, option, and similar elements are not fully modeled.

Ignores comments and whitespace-only Text nodes; nonempty text or an element child prevents a match.

Checks only that the disabled attribute is absent; matching is not limited to form elements that can be enabled.

The first element under the same parent.

The first element with the same localName under the same parent.

Matches Document::focusedElement or a forced focus state.

Currently behaves exactly like :focus; there is no keyboard/pointer input-modality heuristic.

The focused element itself and its ancestor chain.

No matchPseudoClass branch; unknown pseudo-classes return false.

Matches descendants, direct children, adjacent following siblings, or arbitrary following siblings; nested :has is forbidden. The implementation extracts >, +, or ~ only once from the start of the entire argument, rather than implementing a complete relative-selector anchoring model for each branch.

No matchPseudoClass branch; unknown pseudo-classes return false.

No matchPseudoClass branch; unknown pseudo-classes return false.

Matches the hoveredElement ancestor chain, including the element itself and its ancestors; a forced pseudo state is also available.

No matchPseudoClass branch; unknown pseudo-classes return false.

Checks only the indeterminate attribute; live checkbox indeterminate, progress, and radio states are not fully implemented.

Delegates to the limited finiteConstraintValidity implementation; pattern uses only a non-backtracking byte subset with a work budget.

Matches any argument branch and uses the highest argument specificity; an invalid branch containing nested :has may be discarded tolerantly.

Inherits from the nearest lang or xml:lang; accepts comma-separated ident/string lists and RFC 4647 extended language ranges.

The last element under the same parent.

The last element with the same localName under the same parent.

Matches only a elements with href; area is not included in the :link branch.

Matches a dialog in the Document top layer.

Supports selector lists and complex selectors. The parser is error-tolerant; full Selectors 4 rejection semantics for invalid branches are not guaranteed.

Accepts An+B, odd/even, and integers; supports of selector-list and counts only matching elements.

Like nth-child, counting from the end; supports of selector-list.

Applies An+B in reverse order to elements of the same type; does not accept of S.

Accepts An+B, odd/even, and integers; counts elements of the same type and does not accept of S.

Exactly one element under the same parent.

Exactly one element with the same localName under the same parent.

Matches only details and dialog elements with an open attribute; transient picker states are not exposed.

An input, select, or textarea element without a required attribute.

No matchPseudoClass branch; unknown pseudo-classes return false.

Checks only that placeholder exists and the value attribute is empty; this is not the complete form placeholder-display state.

No matchPseudoClass branch; unknown pseudo-classes return false.

Checks only the readonly attribute; the full specification semantics for non-editable elements are not implemented.

No matchPseudoClass branch; unknown pseudo-classes return false.

Checks only for the presence of the required attribute.

Matches Document::documentElement.

The matcher actually matches only documentElement; it does not use the element on which Element::querySelector is called as the scoping root.

No matchPseudoClass branch; unknown pseudo-classes return false.

Matches id against Document::targetElementId; the target must be set by document navigation or the caller.

No matchPseudoClass branch; unknown pseudo-classes return false.

No matchPseudoClass branch; unknown pseudo-classes return false.

Delegates to the limited finiteConstraintValidity implementation; Unknown and NotCandidate do not match. This is not a complete HTML ValidityState implementation.

No browsing history is recorded, so normal execution always returns false; only DevTools ForcedVisited can make it true.

Matches any argument branch; specificity is zero.

parseAtRule has no corresponding branch. It skips the entire statement/block and continues with subsequent rules; this does not implement the feature. @charset is also not implemented as a CSS decoding directive.

Limited numeric width/height/min/max conditions. Unit suffixes are stripped to obtain the number; units such as em are not converted. Does not implement style(), scroll-state, range syntax or full and/or/not logic. Traverses all ancestors with the matching name until one matches, rather than implementing the full nearest-eligible-container model. Requires an existing layoutBox.

parseAtRule has no corresponding branch. It skips the entire statement/block and continues with subsequent rules; this does not implement the feature.

parseAtRule has no corresponding branch. It skips the entire statement/block and continues with subsequent rules; this does not implement the feature.

When a font backend exists, synchronously tries local() and local url() candidates in authored src order. Missing or unsupported candidates continue to fallback. The backend determines font formats. format()/tech() are not used for independent capability selection; a full network webfont lifecycle is not provided.

Accepts normal or a nonnegative percentage, passed through for use in face metrics.

Accepts normal or a nonnegative percentage, passed through for use in face metrics.

Only stored in FontFaceInfo. Document loading does not read it; block/swap/fallback/optional timing is unimplemented.

Used as the CSS family alias for a custom font, with quotes removed.

The @font-face index does not use this descriptor. Check the element property table separately for the support status of an element property with the same name.

The @font-face index does not use this descriptor. Check the element property table separately for the support status of an element property with the same name.

The @font-face index does not use this descriptor. Check the element property table separately for the support status of an element property with the same name.

The @font-face index does not use this descriptor. Check the element property table separately for the support status of an element property with the same name.

The @font-face index does not use this descriptor. Check the element property table separately for the support status of an element property with the same name.

The @font-face index does not use this descriptor. Check the element property table separately for the support status of an element property with the same name.

Accepts normal, bold, or a single integer from 1 to 1000. Range descriptors are not implemented.

Accepts normal or a nonnegative percentage, passed to the font face metrics.

Accepts a nonnegative percentage and scales the selected face glyphs and metrics. This differs from the element font-size-adjust property.

Supports ordered local()/url() candidates. Document uses the first candidate that loads successfully.

Accepts comma-separated Unicode code points, ranges, and trailing ? wildcards. These participate in code point selection for custom font faces.

parseAtRule has no corresponding branch. It skips the entire statement/block and continues with subsequent rules; this does not implement the feature.

parseAtRule has no corresponding branch. It skips the entire statement/block and continues with subsequent rules; this does not implement the feature.

Recursively expands local files, rebases relative URLs, guards against cycles and excessive depth, filters supports conditions and wraps media conditions. Remote URLs are not loaded. The parser has no layer/layer() semantics; leftover text must not be treated as support. The href accepts a direct string or url("local.css"). The import parser does not consume the unquoted Url token from url(local.css), so that form is unreliable.

There is no CSSImportRule layer data or layer assignment. The layer() text is collected into media and usually fails to match as an unknown media type.

Supports from/to, multiple percentage offsets and duplicate keyframes. !important declarations in keyframes are ignored. Actual animatable properties are further limited by the animation implementation.

Supports named and anonymous layers, predeclaration lists, first-seen order across stylesheets, priority for normal unlayered declarations, and reversed layer order for important declarations. Maps names to a single global integer. Nested layers have no parent-name concatenation or hierarchy tree, so full sublayer cascading is not guaranteed.

Supports all/screen/print, not/only, comma-separated OR, and, and limited parenthesized feature:value conditions. Unknown features are ignored. MQ4 range comparisons, conditional OR and full Boolean syntax are unsupported.

Document PDF export enables printMode; normal operation uses screen. The old test name PrintNeverMatches does not mean printing is permanently unsupported.

parseAtRule has no corresponding branch. It skips the entire statement/block and continues with subsequent rules; this does not implement the feature.

Used for PDF pagination; parses 16 margin-box types. The PDF path determines the actual size, margin, named-page, page-pseudo-class, and margin-content capabilities. These rules do not affect on-screen element styles.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. Corner width comes from the left/right margin and height from the top/bottom margin; both must be positive. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. Corner width comes from the left/right margin and height from the top/bottom margin; both must be positive. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.

Actually painted in PDF. The margin on that page edge must be positive. Each edge has up to three slots. Without explicit sizes, space is divided equally among occupied slots. With explicit sizes, start/center/end slots are anchored and auto slots share the remainder equally. Excess explicit sizes are scaled down proportionally. Painting uses the single @page rule selected for that page. A content declaration is required; a background or border alone cannot activate a box without content. See the corresponding entries for shared font, alignment, decoration, and counter limitations.