Tailwind CSS v4.3.4 — Release Notes & Engineering Impact

### Added - Add `@tailwindcss/turbopack`, a Turbopack loader for using Tailwind CSS with Next.js ([#20367](https://github.com/tailwindlabs/tailwindcss/pull/20367)) ### Fixed - Ensure watch mode detects changes to symlinked `@source` files whose real paths aren't otherwise scanned ([#20356](https://github.com/tailwindlabs/tailwindcss/pull/20356)) - Ensure variants using `@scope` wrap generated utilities instead of nesting inside them ([#20369](https://github.com/tailwindlabs/tailwindcss/pull/20369)) - Ensure nested `@scope` rules preserve their scoping semantics when flattened ([#20369](https://github.com/tailwindlabs/tailwindcss/pull/20369)) - Preserve declarations directly inside `@scope` by wrapping them in `:where(:scope)` ([#20369](https://github.com/tailwindlabs/tailwindcss/pull/20369)) - Ensure generated utilities include a space in empty `var()` fallbacks (e.g. `var(--tw-blur,)` → `var(--tw-blur, )`) ([#20373](https://github.com/tailwindlabs/tailwindcss/pull/20373)) - Canonicalization: convert arbitrary breakpoint and container query variants to named equivalents (e.g. `max-[64rem]:flex` → `max-lg:flex`) ([#20380](https://github.com/tailwindlabs/tailwindcss/pull/20380)) - Prevent `@tailwindcss/vite` from crashing on every edit under Vite's experimental `bundledDev` mode ([#20379](https://github.com/tailwindlabs/tailwindcss/pull/20379)) - Ensure `@tailwindcss/oxide` falls back to WASM on platforms without native bindings ([#20383](https://github.com/tailwindlabs/tailwindcss/pull/20383)) - Extract class candidates from Ruby `%w` and `%W` literals using angle brackets or custom delimiters (e.g. `%w<flex>`, `%w|flex|`), including in Slim and Haml templates ([#20387](https://github.com/tailwindlabs/tailwindcss/pull/20387)) - Preserve whitespace in `--default(…)` values in functional `@utility` definitions (e.g. `--default(box alphabetic)` no longer becomes `boxalphabetic`) ([#20392](https://github.com/tailwindlabs/tailwindcss/pull/20392)) - Ensure automatic source detection respects negation-based `.gitignore` files (e.g. `/*` followed by `!/…` patterns) ([#20397](https://github.com/tailwindlabs/tailwindcss/pull/20397)) - Ensure root `theme('…')` namespace lookups in JavaScript plugins and config files return the full namespace object instead of the value of its `DEFAULT` key ([#20399](https://github.com/tailwindlabs/tailwindcss/pull/20399)) - Skip ignored directories when generating watch globs instead of walking their contents on every rebuild ([#20408](https://github.com/tailwindlabs/tailwindcss/pull/20408)) - Drop invalid UTF-8 candidates during class detection ([#20389](https://github.com/tailwindlabs/tailwindcss/pull/20389)) - Prevent `@tailwindcss/vite` from forcing full-page reloads for scanned files that Vite does not handle as modules (e.g. `.php` files) ([#20414](https://github.com/tailwindlabs/tailwindcss/pull/20414)) - Canonicalization: don't merge utilities that reference different theme variables set to CSS-wide keywords like `unset` ([#20417](https://github.com/tailwindlabs/tailwindcss/pull/20417)) - Don't generate utilities when a modifier is used that would otherwise be silently ignored (e.g. `rounded-sm/[5]`, `shadow-sm/foo`, `stroke-2/50`) ([#20419](https://github.com/tailwindlabs/tailwindcss/pull/20419)) - Preserve `and`, `or`, and `not` inside selectors in `supports-[…]` variants (e.g. `supports-[selector(a:not(.foo))]:flex`) ([#20420](https://github.com/tailwindlabs/tailwindcss/pull/20420)) - Don't warn about Angular's `::ng-deep` and `:host-context()` when optimizing CSS ([#20434](https://github.com/tailwindlabs/tailwindcss/pull/20434)) - Don't generate CSS for candidates containing an empty additional modifier (e.g. `bg-red-500/50/` and `group-hover/foo//bar:flex`) ([#20466](https://github.com/tailwindlabs/tailwindcss/pull/20466)) - Ensure `min-*`, `max-*`, and container query variants with decimal values are sorted numerically (e.g. `min-[40.25rem]` before `min-[40.5rem]`) ([#20512](https://github.com/tailwindlabs/tailwindcss/pull/20512)) - Ensure CSS comments ending with `\*/` are closed correctly instead of swallowing the CSS that follows (e.g. `/* C:\temp\*/`) ([#20508](https://github.com/tailwindlabs/tailwindcss/pull/20508)) - Improve style invalidation performance of `group-*` and `peer-*` variants ([#20513](https://github.com/tailwindlabs/tailwindcss/pull/20513)) - Ensure cached compilers release their `loadModule` and `loadStylesheet` callbacks after compilation ([#20531](https://github.com/tailwindlabs/tailwindcss/pull/20531)) - Canonicalization: preserve `&` when moving a pseudo-element into `*` or `**` (e.g. `[&_::before]:flex` → `**:[&::before]:flex`) ([#20550](https://github.com/tailwindlabs/tailwindcss/pull/20550)) - Ensure the `Set.prototype.intersection` polyfill in `canonicalizeCandidates(…)` returns the intersection instead of the first set on Node.js < 22 ([#20562](https://github.com/tailwindlabs/tailwindcss/pull/20562)) - Canonicalization: ensure inline `theme(…)` alphas with more than 2 decimals migrate to a percentage modifier with the same opacity (e.g. `theme(colors.red.500/.12345)` → `text-red-500/[12.345%]`, not `text-red-500/[12.345]`) ([#20563](https://github.com/tailwindlabs/tailwindcss/pull/20563)) - Canonicalization: preserve inline `theme(…)` alphas as an arbitrary percentage when a custom `--opacity-*` theme value would change the opacity (e.g. `theme(colors.red.500/50%)` → `text-red-500/[50%]` with `--opacity-50: 10%`) ([#20563](https://github.com/tailwindlabs/tailwindcss/pull/20563)) - Ensure the `@property` fallback isn't applied in Safari versions that no longer support `margin-trim: inline` ([#20569](https://github.com/tailwindlabs/tailwindcss/pull/20569)) - Treat viewport units like `dvmin` and `svi` and font-relative units like `cap` and `rex` as lengths in arbitrary values (e.g. `text-[10dvmin]` generates `font-size` instead of `color`) ([#20516](https://github.com/tailwindlabs/tailwindcss/pull/20516)) - Write plugin logs to stderr in `tailwindcss canonicalize` so they don't end up in the results on stdout ([#20561](https://github.com/tailwindlabs/tailwindcss/pull/20561)) - Extract class shorthands on later lines when Pug text, comments, or quoted attribute values contain unbalanced brackets, or a quote that doesn't start a string (e.g. `input(pattern=/"/.source)`) ([#20547](https://github.com/tailwindlabs/tailwindcss/pull/20547), [#20572](https://github.com/tailwindlabs/tailwindcss/pull/20572)) - Underline the correct occurrence of an unsupported data type in `--value(…)` warnings ([#20554](https://github.com/tailwindlabs/tailwindcss/pull/20554)) - Canonicalization: prefer an existing candidate when collapsing utilities over another utility with the same default theme value (e.g. `text-foreground text-primary` → `text-primary`, not `text-card-checked-border`) ([#20540](https://github.com/tailwindlabs/tailwindcss/pull/20540)) - Canonicalization: don't collapse utilities into a utility that uses another theme variable with the same default value (e.g. `mt-card mb-card` → `my-card`, not `my-4`) ([#20574](https://github.com/tailwindlabs/tailwindcss/pull/20574)) - Ensure `@tailwindcss/postcss` rewrites relative `url(…)`s of stylesheets that are inlined before it runs (e.g. `@import`s in Vite) in optimized builds ([#20576](https://github.com/tailwindlabs/tailwindcss/pull/20576)) - Drop nested rules that put a combinator after a pseudo-element when using pseudo-element variants (e.g. `selection:*` on a utility with a nested `& > *` rule) ([#20575](https://github.com/tailwindlabs/tailwindcss/pull/20575)) - Don't generate CSS for arbitrary values with unbalanced parentheses or brackets (e.g. `w-[calc(1px]` or `[--x:a[b]`) ([#20577](https://github.com/tailwindlabs/tailwindcss/pull/20577)) - Canonicalization: prevent `collapse: true` from taking exponentially longer when classes are linked through a utility that sets many properties (e.g. `sr-only`) ([#20558](https://github.com/tailwindlabs/tailwindcss/pull/20558)) - Ensure `&` is substituted inside `:-moz-any(…)` and `:-webkit-any(…)` in custom variants (e.g. `@custom-variant firefox (:-moz-any(&));`) ([#20486](https://github.com/tailwindlabs/tailwindcss/pull/20486)) - Ensure the standalone macOS binaries have a valid code signature, so macOS 27 no longer kills them at launch ([#20578](https://github.com/tailwindlabs/tailwindcss/pull/20578)) - Ensure `@tailwindcss/turbopack` and `@tailwindcss/webpack` rebuild when the input CSS changes (e.g. `next dev` with Turbopack no longer serves the CSS of the previous edit) ([#20582](https://github.com/tailwindlabs/tailwindcss/pull/20582)) - Canonicalization: don't drop a utility that sets a `--tw-*` variable when an unrelated property has the same value (e.g. `link mt-4` no longer becomes `mt-4` when `link` sets `margin-top: 16px` and `--tw-translate-x: 16px`) ([#20593](https://github.com/tailwindlabs/tailwindcss/pull/20593)) - Decode single-digit hexadecimal escapes in theme variable and `@utility` names as the CSS spec does (e.g. `@theme { --color-\0: red; }` no longer registers `--color-0`) ([#20591](https://github.com/tailwindlabs/tailwindcss/pull/20591)) - Don't treat `!important` inside strings, comments or `url()` in declaration values as the important flag (e.g. `content: "a !important b"`) ([#20627](https://github.com/tailwindlabs/tailwindcss/pull/20627)) - Parse a custom property at the end of the input when it has no trailing `;` (e.g. `--foo: bar` as the last declaration) ([#20653](https://github.com/tailwindlabs/tailwindcss/pull/20653)) - Keep a declaration without a `;` at the end of the CSS input (e.g. `color: red`) ([#20655](https://github.com/tailwindlabs/tailwindcss/pull/20655))