Add support for @position-try at-rule#1238
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devongovett merged 1 commit intoMay 17, 2026
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Adds parsing and serialization for the CSS Anchor Positioning @position-try at-rule.
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This was referenced Jun 25, 2026
RobinMalfait
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This PR ignores Lightning CSS warnings for the unknow at-rule `@position-try`. This is a temporary fix/workaround until support for `@position-try` lands in Lightning CSS: parcel-bundler/lightningcss#1238 Fixes: #20275 ## Test plan Ran a test based on the issue: Before: ```shellsession ❯ tw -i x.css -o out.css --optimize ≈ tailwindcss v4.3.1 Found 1 warning while optimizing generated CSS: │ position-try-fallbacks: --flip-above; │ } │ @position-try --flip-above { ┆ ^-- Unknown at rule: @position-try ┆ │ top: auto; │ bottom: 0; Done in 29ms ``` After: ```shellsession ❯ tw -i x.css -o out.css --optimize ≈ tailwindcss v4.3.1 Done in 14ms ```
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Adds parsing and serialization support for the CSS Anchor Positioning
@position-tryat-rule.Previously, stylesheets containing
@position-tryproduced anUnknown at ruleerror.Changes
PositionTryRuleinsrc/rules/position_try.rscontaining aDashedIdentname and aDeclarationBlock.CssRuleenum,ToCssimpl, serde deserialization, andunused_symbolsminification handling insrc/rules/mod.rs.AtRulePrelude::PositionTryvariant insrc/parser.rs."position-try"mapping innapi/src/transformer.rs.src/lib.rscovering minified output, pretty-printed output, and nesting inside@supports.Fixes #858.