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conformance · v139

v139 · short-circuiting-var-and-attr — conformance probe

6 assertions drawn from the spec. Each is a single contract the spec text makes. Pass/fail reflects what this browser executed; blocked means the contract was not run because it needs user mediation, hardware, or another unavailable precondition. Open the page in Chrome stable / canary / Firefox / Safari to compare.

browser: spec: https://drafts.csswg.org/css-variables-2/#using-variables chromestatus: #6212939656462336 generated 2026-06-01T08:13:31Z by conformance-author-v1-subagent
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id contract kind verdict detail
var-with-fallback-supported var() with a fallback parses — this is the core syntax the short-circuiting rule applies to. spec ↗ css-supports
attr-with-fallback-supported attr() with a fallback parses — short-circuiting also applies to attr(). css-supports
defined-var-short-circuits-fallback-evaluation When --c is defined, the fallback in var(--c, var(--c)) is not evaluated, so a self-referential fallback is allowed and the declaration is valid. spec ↗ script
var-still-resolves var() still resolves the defined custom property to its value. script
var-fallback-still-used-when-undefined When the custom property is undefined, the fallback is used (this is unchanged by the short-circuiting rule). script
css-supports-recognises-attr-fallback CSS.supports recognises attr() with a fallback as parseable syntax. script