Dataset 20261011-0550-f160c57 · measured 2026-10-11 05:50 UTC

Conformance · CSS properties

Property by property, against a browser

The test suite answers whether the engine passes the specification’s own test pairs, with no browser involved anywhere. This page answers a different question, and the only one on this site that involves another engine: put this declaration on a page, and does our render look like Chrome’s? Every property in the spec universe gets up to a dozen examples, both engines draw each one, and the pixels decide — and where some values match and some do not, the count is printed, not rounded to a verdict.

244

Render like Chrome

every example matches — pixel-exact, or inside the anti-aliasing band

115

Match on some values

some examples match Chrome and some do not; each shows its count

Render differently

no example matches Chrome, or the declaration is swallowed

Not implemented

the parser does not know the name

No example yet

no example we built moves Chrome — our gap, or no static effect

346

Nothing to draw

acts on time, scrolling, input or the medium — said by hand — or no browser ships it

Counts are over all 817 properties in the spec universe, prefixed and draft ones included. A property counts as rendering like Chrome only when every one of its examples does. When some match and some do not, it is listed with its count — flex, 11 of 12 — rather than filed as failing: reporting the best example would make box-shadow look perfect on the strength of a shadow with no blur, and reporting the worst would make flex look broken on the strength of one value.

Standard, unprefixed only

817 properties · showing the first 120

-webkit-align-contentall 8 examples match Chrome8/8 -webkit-align-itemsall 12 examples match Chrome12/12 -webkit-align-selfall 12 examples match Chrome12/12 -webkit-animationrenders differently

-webkit-animation-delaynothing a still page can show

-webkit-animation-directionall 2 examples match Chrome2/2 -webkit-animation-durationpixel-exact

-webkit-animation-fill-modenothing a still page can show

-webkit-animation-iteration-countnothing a still page can show

-webkit-animation-namerenders differently

-webkit-animation-play-statenothing a still page can show

-webkit-animation-timing-functionnothing a still page can show

-webkit-text-size-adjustnothing a still page can show

-webkit-text-stroke2 of 6 examples match Chrome2/6 -webkit-text-stroke-colorrenders differently — 0 of 2 examples match0/2 -webkit-text-stroke-width3 of 6 examples match Chrome3/6 -webkit-transformall 9 examples match Chrome9/9 -webkit-transform-originall 12 examples match Chrome12/12 -webkit-transform-stylerenders differently

-webkit-transitionnothing a still page can show

-webkit-transition-delaynothing a still page can show

-webkit-transition-durationnothing a still page can show

-webkit-transition-propertynothing a still page can show

-webkit-transition-timing-functionnothing a still page can show

-webkit-user-selectnothing a still page can show

accent-color1 of 2 examples match Chrome1/2 align-contentall 8 examples match Chrome8/8 align-itemsall 12 examples match Chrome12/12 align-selfall 12 examples match Chrome12/12 alignment-baselinenot implemented — 0 of 5 examples match0/5 allall 2 examples match Chrome2/2

anchor-namenothing a still page can show

anchor-scopenothing a still page can show

animationrenders differently animation-compositionnothing a still page can show animation-delaynothing a still page can show

animation-delay-endno browser to compare against

animation-delay-startno browser to compare against

animation-directionall 2 examples match Chrome2/2 animation-durationpixel-exact animation-fill-modepixel-exact animation-iteration-countnothing a still page can show animation-namerenders differently animation-play-statenothing a still page can show

animation-rangenothing a still page can show

animation-range-centerno browser to compare against

animation-range-endnothing a still page can show

animation-range-startnothing a still page can show

animation-timelinenothing a still page can show

animation-timing-functionnothing a still page can show animation-triggernothing a still page can show appearancerenders differently — 0 of 3 examples match0/3 aspect-ratiopixel-exact backdrop-filternot implemented — 0 of 11 examples match0/11 backface-visibilitypixel-exact backgroundall 3 examples match Chrome3/3 background-attachmentparsed, no effect background-blend-mode8 of 12 examples match Chrome8/12 background-clipall 2 examples match Chrome2/2 background-colorall 2 examples match Chrome2/2 background-imagebelow the visible threshold background-originall 2 examples match Chrome2/2 background-positionall 12 examples match Chrome12/12

background-position-blockno browser to compare against

background-position-inlineno browser to compare against

background-position-xall 8 examples match Chrome8/8 background-position-yall 8 examples match Chrome8/8 background-repeatall 5 examples match Chrome5/5

background-repeat-blockno browser to compare against

background-repeat-inlineno browser to compare against

background-repeat-xno browser to compare against

background-repeat-yno browser to compare against

background-sizeall 6 examples match Chrome6/6

background-tbdno browser to compare against

baseline-shiftparsed, no effect — 0 of 8 examples match0/8

What the verdicts mean

✓pixel-exact: Our rendering of the example is identical to Chrome's, pixel for pixel — no further apart than the example's own noise floor.
≈below the visible threshold: Differs from Chrome only inside the measured anti-aliasing band (maximum channel distance 3 of 255). Curves, rotation and gradients land here.
◐matches Chrome on some values: Some of the examples match Chrome and some do not. The count beside the verdict says how many — 11 of 12 — and the values that differ are listed on the property page. It is neither a pass nor a failure, and filing it under either would be a lie in one direction.
✕renders differently: The property takes effect, but our pixels are not Chrome's. The difference map on this page shows where.
✕parsed, no effect: The parser accepts the name, yet our rendering is byte-identical with and without the declaration while Chrome's is not. The declaration is being swallowed.
–not implemented: The engine's CSS parser does not know this property name, so the declaration is dropped where it is read.
?no example yet: No example we built changes what Chrome draws, so there is nothing to judge the engine against. That is our gap in the sample set as often as it is the property having no static effect, and we cannot tell the two apart by measurement — so both stay in this one bucket, with the number of candidates tried published beside it.
·nothing a still page can show: By its definition this property acts on something a rendered page does not have — time, scrolling, the pointer, the output medium. We say so by hand, and say that it is said by hand: the search still tried its candidates, and had Chrome reacted to any of them the measurement would have won over this note.
?no browser to compare against: Chrome does not implement this property, so no example can demonstrate it and there is no reference to judge against. Usually a draft that has not shipped anywhere.

How it was measured

Each example is rendered twice — Chrome 148.0.7778.96 and our engine — and compared. Before a comparison counts, Chrome has to react to the declaration at all: an example where the browser itself draws the same picture with and without the property proves nothing, so it is thrown out. The search tried up to 40 candidate values per property and the sensitivity floor was 40pixels, which is what “Chrome did not react” means here.

The atlas is a snapshot from its own run (2026-10-11), engine eae3a64. The engine has moved since: conformance publishes 146bce3 today, so a verdict here may be behind the current build.

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