CSS properties

Only maps horizontal-tb plus direction: RTL swaps inline start/end, block remains top/bottom, and size remains width/height. A vertical writing-mode does not change this mapping.

Lengths, percentages, and math trees are stored separately. Percentage resolution depends on whether the containing block size is definite or indefinite. Intrinsic sizing uses IntrinsicSizer, with separate constraints for replaced elements, flex, grid, and tables. anchor-size() is not included.

Mapping follows horizontal-tb and direction only. RTL swaps inline start/end; block maps to top/bottom, and sizes map to width/height. Vertical writing-mode does not change this mapping.

The current property registry and StyleCore/Extras have no implementation that uses this element property. Tokenizer acceptance of its name, inclusion in the @supports allowlist, or the existence of imported tests does not establish support.

Lengths, percentages, and math trees are stored separately. Percentage resolution depends on whether the containing block size is definite or indefinite. Intrinsic sizing uses IntrinsicSizer, with separate constraints for replaced elements, flex, grid, and tables. anchor-size() is not included.

Only min/max ratios are supported. Exact aspect-ratio conditions and range comparisons are unsupported.

Color depth is fixed at 8; monochrome is fixed at false.

Fixed to hover and fine; does not query actual device capabilities.

Uses viewportHeight >= viewportWidth to determine portrait orientation.

Fixed to light; does not read system or theme preferences.

Fixed to no-preference; reduce returns false.

Converts dpi/dpcm/dppx/x, but device resolution is fixed at 96dpi and does not reflect the window DPR.

Uses the current viewport with exact pixel equality; no range syntax. The length parser is very limited: em is fixed at 16px, and rem hits both the em and rem branches, so it cannot reliably follow the root font size.

Supports nested math, parentheses, arithmetic operator precedence and numeric type validation. Limited by each property's accepted types and the depth budget.

Mapping follows horizontal-tb and direction only. RTL swaps inline start/end; block maps to top/bottom, and sizes map to width/height. Vertical writing-mode does not change this mapping.

Lengths, percentages, and math trees are stored separately. Percentage resolution depends on whether the containing block size is definite or indefinite. Intrinsic sizing uses IntrinsicSizer, with separate constraints for replaced elements, flex, grid, and tables. anchor-size() is not included.

Mapping follows horizontal-tb and direction only. RTL swaps inline start/end; block maps to top/bottom, and sizes map to width/height. Vertical writing-mode does not change this mapping.

Lengths, percentages, and math trees are stored separately. Percentage resolution depends on whether the containing block size is definite or indefinite. Intrinsic sizing uses IntrinsicSizer, with separate constraints for replaced elements, flex, grid, and tables. anchor-size() is not included.

plus-lighter and plus-darker are not implemented.

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

Supports nested math, parentheses, arithmetic operator precedence and numeric type validation. Limited by each property's accepted types and the depth budget.

Applies to images in replaced elements.

Supports keywords, lengths/percentages and edge offsets.

Supports percentage conversion for L and a/b, and alpha. Compresses results into 8-bit sRGB and clamps out-of-gamut components. Does not provide the full missing-component or relative-color model.

Supports L/C percentages, hue angles and alpha. Clamps intermediate matrix values and returns 8-bit sRGB; wide gamut is not preserved.

Applies to the entire element and its subtree through a transparency layer.

Layout sorts items by order; it does not change DOM order.

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.

Expands into three longhands.

Supports currentColor. invert is not implemented.

Positive values move the outline outward and negative values inward. It does not affect layout dimensions. For inline content spanning lines, line fragments form a merged outline.

Outlines for inline content spanning lines are painted from the union of its fragments.

A positive used value is at least 1px; values above 1px are rounded down.

overlay is treated as auto for compatibility. An axis that is neither visible nor clip causes the other visible axis to become auto. hidden/scroll/auto establish a BFC; clip works with overflow-clip-margin.

Selects the reference box and outward extension for the visible clipping boundary. Percentages are not accepted.

word-wrap is a compatibility alias for overflow-wrap. anywhere/break-word participate in emergency line breaking, while intrinsic-sizing paths preserve their differences.

overlay is treated as auto for compatibility. An axis that is neither visible nor clip causes the other visible axis to become auto. hidden/scroll/auto establish a BFC; clip works with overflow-clip-margin.

overlay is treated as auto for compatibility. An axis that is neither visible nor clip causes the other visible axis to become auto. hidden/scroll/auto establish a BFC; clip works with overflow-clip-margin.

The declaration layer expands the value to four sides. padding does not accept auto.

Block/inline mapping follows horizontal-tb only; the inline direction follows direction. The ordinary paired inset/margin/padding shorthands split one or two values at top-level whitespace.

Mapping follows horizontal-tb and direction only. RTL swaps inline start/end; block maps to top/bottom, and sizes map to width/height. Vertical writing-mode does not change this mapping.

Mapping follows horizontal-tb and direction only. RTL swaps inline start/end; block maps to top/bottom, and sizes map to width/height. Vertical writing-mode does not change this mapping.

Percentages are resolved against the containing block inline size during layout. Affine calc expressions retain px and percentage terms; non-affine expressions have limitations because they are converted to numbers during style resolution.

Block/inline mapping follows horizontal-tb only; the inline direction follows direction. The ordinary paired inset/margin/padding shorthands split one or two values at top-level whitespace.

Mapping follows horizontal-tb and direction only. RTL swaps inline start/end; block maps to top/bottom, and sizes map to width/height. Vertical writing-mode does not change this mapping.

Mapping follows horizontal-tb and direction only. RTL swaps inline start/end; block maps to top/bottom, and sizes map to width/height. Vertical writing-mode does not change this mapping.

Percentages are resolved against the containing block inline size during layout. Affine calc expressions retain px and percentage terms; non-affine expressions have limitations because they are converted to numbers during style resolution.

Percentages are resolved against the containing block inline size during layout. Affine calc expressions retain px and percentage terms; non-affine expressions have limitations because they are converted to numbers during style resolution.

Percentages are resolved against the containing block inline size during layout. Affine calc expressions retain px and percentage terms; non-affine expressions have limitations because they are converted to numbers during style resolution.

PDF pagination uses pageName to select the matching @page name and per-page decoration rules. If a physical page has multiple names, it retains the first nonempty name. When the entire tree has one name, that named page may override the generic margin; mixed-name geometry still uses the generic layer. printToPDF options override the final page width and height. This does not paginate ordinary screen layout.

Shares the break-after field. The legacy value always maps to page.

Shares the break-before field. The legacy value always maps to page.

Shares the break-inside field. The legacy value always maps to page.

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

The CSS 3D geometry path is independent of Filament and the legacy 3D engine, which are disabled by default.

The CSS 3D geometry path is independent of Filament and the legacy 3D engine, which are disabled by default.

A single value or two single-word values can be expanded. Parsing splits at the first space, so multiword components such as safe center and first baseline cannot be separated reliably. Use the longhands for these values.

A single value or two single-word values can be expanded. Parsing splits at the first space, so multiword components such as safe center and first baseline cannot be separated reliably. Use the longhands for these values.

A single value or two single-word values can be expanded. Parsing splits at the first space, so multiword components such as safe center and first baseline cannot be separated reliably. Use the longhands for these values.

HTML box hit testing supports auto and none; SVG-specific values such as visiblePainted, fill, and stroke are not implemented.

absolute and fixed use the shared absolute-positioning pipeline. sticky works with scroll-offset replay.

The generic value/length-math parser has no semantics for this function. Storing the text of an unknown function does not establish support.

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

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

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

Custom quotation marks at multiple nesting levels are supported. The auto language table distinguishes only fr from the default curly quotation marks; it is not a complete language quotation database.

Supports circles/ellipses, four size keywords, explicit radii and center positions, including some affine calc coordinates. Defaults to ellipse/farthest-corner/center. Supports single-position and double-position color stops, affine length/percentage/calc stops and color hints. Stop correction is deferred until the actual gradient length is known. Explicit interpolation spaces are limited to srgb/srgb-linear/xyz/hsl/lch; the last two support shorter/longer/increasing/decreasing hue. Spaces such as lab/oklab/oklch/display-p3 are not included. Color hints use a bounded approximation with nine additional color stops. The background, border and list-image paths use these features; the mask path does not inherit this full capability set.

The generic value/length-math parser has no semantics for this function. Storing the text of an unknown function does not establish support.

The element cascade has a root-font measurement callback. Without a measurer, or through other entry points, it may fall back to proportional approximations. The generic rawLengthToPx fallback does not provide actual root-font precision.

The element cascade has a root-font measurement callback. Without a measurer, or through other entry points, it may fall back to proportional approximations. The generic rawLengthToPx fallback does not provide actual root-font precision.

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

Supports nested math, parentheses, arithmetic operator precedence and numeric type validation. Limited by each property's accepted types and the depth budget.

Angular color stops are not implemented: the shared parseGradientStopPosition explicitly rejects deg/rad/turn. Support for the from angle does not imply support for angle stops. The backend converts the first and last positions into sweep start/end angles and repeats. Supports single-position and double-position color stops, affine length/percentage/calc stops and color hints. Stop correction is deferred until the actual gradient length is known. Explicit interpolation spaces are limited to srgb/srgb-linear/xyz/hsl/lch; the last two support shorter/longer/increasing/decreasing hue. Spaces such as lab/oklab/oklch/display-p3 are not included. Color hints use a bounded approximation with nine additional color stops. The background, border and list-image paths use these features; the mask path does not inherit this full capability set.

Supports repetition periods that differ from the full box width, degenerate zero periods and negative stops. Supports single-position and double-position color stops, affine length/percentage/calc stops and color hints. Stop correction is deferred until the actual gradient length is known. Explicit interpolation spaces are limited to srgb/srgb-linear/xyz/hsl/lch; the last two support shorter/longer/increasing/decreasing hue. Spaces such as lab/oklab/oklch/display-p3 are not included. Color hints use a bounded approximation with nine additional color stops. The background, border and list-image paths use these features; the mask path does not inherit this full capability set.

The radial shader radius is reduced to one period and repeated. Supports single-position and double-position color stops, affine length/percentage/calc stops and color hints. Stop correction is deferred until the actual gradient length is known. Explicit interpolation spaces are limited to srgb/srgb-linear/xyz/hsl/lch; the last two support shorter/longer/increasing/decreasing hue. Spaces such as lab/oklab/oklch/display-p3 are not included. Color hints use a bounded approximation with nine additional color stops. The background, border and list-image paths use these features; the mask path does not inherit this full capability set.

Parsed and stored, but no runtime code consumes it to resize an element by dragging (window resizing is a separate feature). In src, ResizeType appears only in style dispatch; no resize handle, pointer-dragging logic, or layout-field consumer was found. CSS parsing tests do not establish that interactive resizing is implemented.

Supports CSS-wide keywords. Explicit inherit takes the parent computed value; revert rolls back the current origin; revert-layer rolls back the current layer, with inline declarations handled separately. CSS-wide keywords introduced through variable substitution may not cover all static layer semantics.

Supports CSS-wide keywords. Explicit inherit takes the parent computed value; revert rolls back the current origin; revert-layer rolls back the current layer, with inline declarations handled separately. CSS-wide keywords introduced through variable substitution may not cover all static layer semantics.

The element cascade has a root-font measurement callback. Without a measurer, or through other entry points, it may fall back to proportional approximations. The generic rawLengthToPx fallback does not provide actual root-font precision.

Accepts legacy comma-separated and modern space/slash numeric forms. Numbers and percentages are truncated and rounded to 8-bit values. Does not implement the full strict CSS Color grammar: unknown tokens receive error tolerance and relative rgb(from ...) is not modeled. Accepted malformed input must not be presented as a feature.

The element cascade has a root-font measurement callback. Without a measurer, or through other entry points, it may fall back to proportional approximations. The generic rawLengthToPx fallback does not provide actual root-font precision.

Percentages are resolved during layout. Affine calc expressions retain px and percentage terms; non-affine expressions are converted to numbers during style resolution, so a complete container reference cannot be claimed for every function.

Generic rawLengthToPx approximates root line height as rootFontSize * 1.2; it has no actual root computed line-height parameter.

Supports deg/rad/turn and axis rotation. grad is handled by the rad substring branch; calc is not implemented. This is not complete angle syntax support.

Supports nested math, parentheses, arithmetic operator precedence and numeric type validation. Limited by each property's accepted types and the depth budget. Rounding strategies nearest/up/down/to-zero are supported; omitted step defaults to 1.

Used by flex and grid; column-gap also serves multicolumn layout. Affine calc expressions retain px and percentage terms. Non-affine math functions still use a two-sample approximation. normal is zero in flex/grid and 1em for the multicolumn column gap.

The border-style shorthand accepts color functions containing whitespace. It changes only supplied components and does not reset omitted components. List shorthand syntax is not fully implemented.

Controls breaks in rule lines at spanning items and intersections, and is used by painting.

Accepts color lists and repeat groups. currentColor resolves to the current text color when the style is applied.

Insets the corresponding edge or interior endpoint of a rule line. Percentages are retained until painting; calc is currently unsupported.

Insets the corresponding edge or interior endpoint of a rule line. Percentages are retained until painting; calc is currently unsupported.

Writes the same value to all four edge/interior start/end endpoints. This value parser does not accept calc.

Insets the corresponding edge or interior endpoint of a rule line. Percentages are retained until painting; calc is currently unsupported.

Insets the corresponding edge or interior endpoint of a rule line. Percentages are retained until painting; calc is currently unsupported.

The parser accepts more styles than some gap-painting paths can draw. Each decoration context has its own visible-style checks; accepting all border styles does not establish complete CSS Gap Decorations coverage.

normal maps to auto. Controls segment visibility according to adjacent or surrounding items.

Converts single values and lists to actual lengths. In lists and shorthands, thin/medium/thick resolve to 1/3/5px. Used by flex, grid, and multicolumn painting.

Writes supplied components to both axes. Omitted components are not reset, and list shorthand syntax is not implemented.

Writes break to both axes.

Writes a scalar value to both axes; lists are not implemented.

Controls the painting order where row and column rules overlap.

Writes to both axes. The shorthand value branch does not accept groove/ridge/inset/outset/hidden.

Writes visibility to both axes.

Writes scalar column/row values. Does not implement the comma-separated lists or repeat protocol available in the axis longhands.

Used for transition/animation times. Negative delay is available; the limited validator rejects negative duration.

The helper only parses plain numbers. Percentage scale values and calc are not implemented.

Element::scrollTo reads this field for its default behavior. This does not guarantee smooth animation for every input or scrolling path. When behavior is not explicitly supplied, Element::scrollTo reads it; smooth uses the scroll animation tick. Native wheel input is not necessarily smoothed.

The shorthand fills four sides from numeric prefixes; non-px units, percentages, auto, and calc are not parsed with their full semantics. It affects snap offsets. Each whitespace token is currently read as a numeric prefix: 10em becomes 10px, and calc is split apart. Use px or longhands. Use was found only in scroll snap; scrollIntoView does not consume this field.

Converted by resolveLength and used in scroll snap. Percentages and auto have no separate storage or deferred evaluation. Lengths are converted to px for snapping; percentages are not retained for resolution against the container size. scroll-padding:auto has no dedicated used-value protocol.

Converted by resolveLength and used in scroll snap. Percentages and auto have no separate storage or deferred evaluation. Lengths are converted to px for snapping; percentages are not retained for resolution against the container size. scroll-padding:auto has no dedicated used-value protocol.

Converted by resolveLength and used in scroll snap. Percentages and auto have no separate storage or deferred evaluation. Lengths are converted to px for snapping; percentages are not retained for resolution against the container size. scroll-padding:auto has no dedicated used-value protocol.

Converted by resolveLength and used in scroll snap. Percentages and auto have no separate storage or deferred evaluation. Lengths are converted to px for snapping; percentages are not retained for resolution against the container size. scroll-padding:auto has no dedicated used-value protocol.

The shorthand fills four sides from numeric prefixes; non-px units, percentages, auto, and calc are not parsed with their full semantics. It affects snap offsets. Each whitespace token is currently read as a numeric prefix: 10em becomes 10px, and calc is split apart. Use px or longhands. Use was found only in scroll snap; scrollIntoView does not consume this field.

Converted by resolveLength and used in scroll snap. Percentages and auto have no separate storage or deferred evaluation. Lengths are converted to px for snapping; percentages are not retained for resolution against the container size. scroll-padding:auto has no dedicated used-value protocol.

Converted by resolveLength and used in scroll snap. Percentages and auto have no separate storage or deferred evaluation. Lengths are converted to px for snapping; percentages are not retained for resolution against the container size. scroll-padding:auto has no dedicated used-value protocol.

Converted by resolveLength and used in scroll snap. Percentages and auto have no separate storage or deferred evaluation. Lengths are converted to px for snapping; percentages are not retained for resolution against the container size. scroll-padding:auto has no dedicated used-value protocol.

Converted by resolveLength and used in scroll snap. Percentages and auto have no separate storage or deferred evaluation. Lengths are converted to px for snapping; percentages are not retained for resolution against the container size. scroll-padding:auto has no dedicated used-value protocol.

Used only for candidates that are direct child elements. The first value is the block axis, and the second is the inline axis. Snap searches inspect only direct child elements and use physical x/y coordinates.

Only stores the field. Snap calculations do not read always, so it does not prevent crossing snap points. scrollSnapStop appears only in style application, inheritance, metadata, and serialization; computeSnapOffset does not consume always. Preventing skipped snap points must not be claimed.

Candidates are direct child elements; block/inline map to Y/X. The proximity threshold is 40% of the container, rather than a complete specification model. The scroll setter finds the nearest snap point among direct DOM child elements. The proximity threshold is 0.4 times the container dimension. The block/inline mapping to Y/X does not change with writing-mode.

Color parsing accepts functions containing whitespace and currentColor. Used by KUI-drawn scrollbars. This inherited property is consumed by scrollbar painting.

Reserves scrollbar space in block/flex/grid layout and at the viewport root. Used by layout and by root/child scrollbar painting. Combinations with scrollbar overlay mode still require image-based acceptance checks.

Used by KUI-drawn scrollbars and layout measurements. Affects scrollbar thickness and visibility.

The generic value/length-math parser has no semantics for this function. Storing the text of an unknown function does not establish support.

The generic value/length-math parser has no semantics for this function. Storing the text of an unknown function does not establish support.

The generic value/length-math parser has no semantics for this function. Storing the text of an unknown function does not establish support.

Stores only stepCount and the jumpStart Boolean: jump-both is treated as start and jump-none as end. The full four-value jump-position model is absent. Values below 1 are normalized to 1.

Applies only to internal SVG CSS and is handled by the SVG backend. It is not a ComputedStyle property of ordinary HTML boxes. The backend determines inheritance, colors/units, paint servers, and selector details. See the SVG internal CSS handoff entry for limits on forwarding host grouping rules.

Applies only to internal SVG CSS and is handled by the SVG backend. It is not a ComputedStyle property of ordinary HTML boxes. The backend determines inheritance, colors/units, paint servers, and selector details. See the SVG internal CSS handoff entry for limits on forwarding host grouping rules.

Applies only to internal SVG CSS and is handled by the SVG backend. It is not a ComputedStyle property of ordinary HTML boxes. The backend determines inheritance, colors/units, paint servers, and selector details. See the SVG internal CSS handoff entry for limits on forwarding host grouping rules.

Applies only to internal SVG CSS and is handled by the SVG backend. It is not a ComputedStyle property of ordinary HTML boxes. The backend determines inheritance, colors/units, paint servers, and selector details. See the SVG internal CSS handoff entry for limits on forwarding host grouping rules.

Uses a fixed light palette and does not read OS theme or high-contrast settings. AccentColor here is a color keyword; it does not mean the accent-color property takes effect.

Used in whitespace-preserving modes. Numeric tab stops and length-based tab stops are handled separately.

Provides auto intrinsic column sizing and fixed first-row/column width distribution algorithms. fixed is used when the table has a definite size.

The generic value/length-math parser has no semantics for this function. Storing the text of an unknown function does not establish support.

start/end resolve according to direction. match-parent is not implemented; unknown strings leave the current value unchanged.

Adjusts the last line or a line ending with a forced break. Direction-sensitive values are consumed.

The current property registry and StyleCore/Extras have no implementation that uses this element property. Tokenizer acceptance of its name, inclusion in the @supports allowlist, or the existence of imported tests does not establish support.

Parsing the shorthand resets all four components. The blink syntax is accepted but does not produce blinking. Decoration lines include static lines and semantic error indicators.

Used in propagated decoration styles and the actual painted color.

blink is accepted but is neither painted nor animated. spelling-error and grammar-error have separate static decoration-line flags.

Ink-skipping is painted; all and auto remain distinct modes.

The decoration-line painter uses all five line styles.

Percentages are relative to the computed font-size. from-font uses font metrics; auto uses the default stroke width.

Sets style/color, but not position. Inherits the longhand limitations, including the transparent-color sentinel and first-code-point behavior.

alpha=0 serves as the currentColor sentinel, so an authored transparent or fully transparent color cannot correctly remain transparent.

Positions emphasis marks in horizontal and vertical text. A standalone right/left is accepted for compatibility; missing components default to over/right.

Skips marks by code-point classification. none cannot be combined with the other values.

A custom string retains only its first code point, not a complete grapheme cluster. Specifying only a fill value defaults the shape to circle.

Accepts negative values, percentages, and affine calc. each-line/hanging can be combined in either declaration order. Source comments for the current carrier retain line-breaking discrepancies for complex positive indents, RTL/center/right alignment, adjacent atomic boxes, and similar cases. Full conformance must not be claimed.