Fixed

• Support --watch --poll[=ms] in @tailwindcss/cli when filesystem events are unreliable or unavailable (#20297)
• Canonicalization: match arbitrary hex colors against theme colors case-insensitively (e.g. bg-[#fff] and bg-[#FFF] → bg-white) (#20298)
• Prevent Preflight from overriding Firefox's native iframe:focus-visible outline styles (#20292)
• Ensure theme('colors.foo') in JS plugins resolves correctly when both --color-foo and --color-foo-bar exist (#20299)
• Ensure fractional opacity modifiers work with named shadow sizes like shadow-sm/12.5, text-shadow-sm/12.5, drop-shadow-sm/12.5, and inset-shadow-sm/12.5 (#20302)
• Parse selectors like [data-foo]div as two selectors instead of one (#20303)
• Ensure @tailwindcss/postcss rebuilds when a preprocessor like Sass changes the input CSS without changing the input file on disk (#20310)
• Ensure CSS nesting is handled even when Lightning CSS isn't run, such as in @tailwindcss/browser and Tailwind Play (#20124)
• Prevent achromatic theme colors from shifting hue when mixed in polar color spaces like oklch (#20314)
• Ensure --spacing(0) is optimized to 0px instead of 0 so it remains a <length> when used in calc(…) (#20319)
• Load @parcel/watcher only when needed in @tailwindcss/cli --watch mode, so one-off builds and --watch --poll work when @parcel/watcher can't be loaded (#20325)
• Use explicit platform fonts instead of system-ui and ui-sans-serif so CJK text respects the page's lang attribute on Windows (#20318)
• Prevent @tailwindcss/upgrade from rewriting ignored files when run from a subdirectory (#20329)
• Ensure earlier @source rules pointing to nested files are scanned when later @source rules point to files in parent folders (#20335)
• Prevent @tailwindcss/vite from triggering full page reloads when scanned files are processed by Vite but haven't been loaded as modules yet (#20336)

Fixed

• Support bare spacing values for auto-rows-* and auto-cols-* utilities (e.g. auto-rows-12 and auto-cols-16) (#20229)
• Prevent @tailwindcss/cli in --watch mode from crashing on Windows when @source points to a directory that doesn't exist (#20242)
• Prevent @tailwindcss/vite from crashing in Deno v2.8.x when context.parentURL is not a valid URL (#20245)
• Ensure @tailwindcss/cli in --watch mode rebuilds when the input CSS file changes in an ignored directory (#20246)
• Allow @variant rules used in addBase(…) to use custom variants defined later (#20247)
• Prevent @tailwindcss/vite from crashing during HMR when scanned files or directories are deleted (#20259)
• Generate font-size instead of color declarations for text-[--spacing(…)] (#20260)
• Prevent @source patterns from scanning unrelated sibling files and folders (#20263)
• Extract class candidates adjacent to Template Toolkit delimiters like %]…[% in .tt, .tt2, and .tx files (#20269)
• Extract class candidates from conditional Maud syntax like p.text-black[condition] (#20269)
• Prevent @position-try rules from triggering unknown at-rule warnings when optimizing CSS (#20277)
• Support class suggestions for named opacity modifiers from --opacity theme values (#20287)
• Prevent type errors in @tailwindcss/postcss when used with newer PostCSS patch releases (#20289)

Added

• Add --silent option to suppress output in @tailwindcss/cli (#20100)

Fixed

• Remove deprecation warnings by using Module#registerHooks instead of Module#register on Node 26+ (#20028)
• Canonicalization: don't crash when plugin utilities throw for unsupported values (#20052)
• Allow @apply to be used with CSS mixins (#19427)
• Ensure not-* correctly negates @container queries, including style(…) queries (#20059)
• Ensure drop-shadow-* color utilities work with custom shadow values containing calc(…) (#20080)
• Fix 'Sourcemap is likely to be incorrect' warnings when using @tailwindcss/vite (#20103)
• Ensure @tailwindcss/webpack can be installed in Rspack projects without requiring webpack as a peer dependency (#20027)
• Canonicalization: don't suggest invalid calc(…) expressions (e.g. px-[calc(1rem+0px)] → px-[calc(1rem+0)]) (#20127)
• Canonicalization: avoid suggesting large spacing-scale values for arbitrary lengths (e.g. left-[99999px] → left-[99999px], not left-24999.75) (#20130)
• Ensure @tailwindcss/cli in --watch mode recovers when a tracked dependency is deleted and restored (#20137)
• Ensure standalone @tailwindcss/cli binaries are ignored when scanning for class candidates (#20139)
• Ensure class candidates are extracted from Twig addClass(…) and removeClass(…) calls (#20198)
• Don't crash in the Ruby or Vue preprocessors when scanning files containing invalid UTF-8 bytes (#19588)
• Allow @variant to be used inside addBase (#19480)
• Ensure @source globs with symlinks are preserved (#20203)
• Ensure later @source rules can re-include files excluded by earlier @source not rules (#20203)
• Upgrade: don't migrate empty class rules to invalid @utility rules (#20205)
• Ensure transitions between inset-shadow-none and other inset shadows work correctly (#20208)
• Ensure explicitly referenced @source directories are scanned even when ignored by git (#20214)
• Ensure @source globs ending in **/* preserve dynamic path segments to avoid scanning too many files (#20217)
• Canonicalization: don't fold calc(…) divisions when the result would require high precision (e.g. w-[calc(100%/3.5)] → w-[calc(100%/3.5)], not w-[28.571428571428573%]) (#20221)
• Serve ESM type declarations to ESM importers of @tailwindcss/postcss (#20228)

Changed

• Generate 0 instead of calc(var(--spacing) * 0) for spacing utilities like m-0 and left-0 (#20196)
• Generate var(--spacing) instead of calc(var(--spacing) * 1) for spacing utilities like m-1 and left-1 (#20196)

Added

• Add @container-size utility (#18901)
• Add scrollbar-{auto,thin,none} utilities for scrollbar-width, and scrollbar-thumb-* / scrollbar-track-* color utilities for scrollbar-color (#19981, #20019)
• Add scrollbar-gutter-* utilities (#20018)
• Add zoom-* utilities (#20020)
• Add tab-* utilities (#20022)
• Allow using @variant with stacked variants (e.g. @variant hover:focus { … }) (#19996)
• Allow using @variant with compound variants (e.g. @variant hover, focus { … }) (#19996)
• Support --default(…) in --value(…) and --modifier(…) for functional @utility definitions (#19989)

Fixed

• Ensure @plugin resolves package JavaScript entries instead of browser CSS entries when using @tailwindcss/vite (#19949)
• Fix relative @import and @plugin paths resolving from the wrong directory when using @tailwindcss/vite (#19965)
• Ensure CSS files containing @variant are processed by @tailwindcss/vite (#19966)
• Resolve imports relative to base when result.opts.from is not provided when using @tailwindcss/postcss (#19980)
• Canonicalization: preserve significant _ whitespace in arbitrary values (#19986)
• Canonicalization: add parentheses when removing whitespace from arbitrary values would hurt readability (e.g. w-[calc(100%---spacing(60))] → w-[calc(100%-(--spacing(60)))]) (#19986)
• Canonicalization: preserve the original unit in arbitrary values instead of normalizing to base units (e.g. -mt-[20in] → mt-[-20in], not mt-[-1920px]) (#19988)
• Canonicalization: migrate arbitrary :has() variants from [&:has(…)] to has-[…] (#19991)
• Upgrade: don’t migrate inline style attributes (e.g. style="flex-grow: 1" → style="flex-grow: 1", not style="grow: 1") (#19918)
• Allow multiple @utility definitions with the same name but different value types (#19777)
• Export missing PluginWithConfig type from tailwindcss/plugin to fix errors when inferring plugin config types (#19707)
• Ensure start and end legacy utilities without values do not generate CSS (#20003)
• Ensure --value(…) is required in functional @utility definitions (#20005)
• Canonicalization: preserve required whitespace around operators in negated arbitrary values (e.g. -left-[(var(--a)+var(--b))]) (#20011)

Fixed

• Ensure imports in @import and @plugin still resolve correctly when using Vite aliases in @tailwindcss/vite (#19947)

Fixed

• Canonicalization: improve canonicalizations for tracking-* utilities by preferring non-negative utilities (e.g. -tracking-tighter → tracking-wider) (#19827)
• Fix crash due to invalid characters in candidate (exceeding valid unicode code point range) (#19829)
• Ensure query params in imports are considered unique resources when using @tailwindcss/webpack (#19723)
• Canonicalization: collapse arbitrary values into shorthand utilities (e.g. px-[1.2rem] py-[1.2rem] → p-[1.2rem]) (#19837)
• Canonicalization: collapse border-{t,b}-* into border-y-*, border-{l,r}-* into border-x-*, and border-{t,r,b,l}-* into border-* (#19842)
• Canonicalization: collapse scroll-m{t,b}-* into scroll-my-*, scroll-m{l,r}-* into scroll-mx-*, and scroll-m{t,r,b,l}-* into scroll-m-* (#19842)
• Canonicalization: collapse scroll-p{t,b}-* into scroll-py-*, scroll-p{l,r}-* into scroll-px-*, and scroll-p{t,r,b,l}-* into scroll-p-* (#19842)
• Canonicalization: collapse overflow-{x,y}-* into overflow-* (#19842)
• Canonicalization: collapse overscroll-{x,y}-* into overscroll-* (#19842)
• Read from --placeholder-color instead of --background-color for placeholder-* utilities (#19843)
• Upgrade: ensure files are not emptied out when killing the upgrade process while it's running (#19846)
• Upgrade: use config.content when migrating from Tailwind CSS v3 to Tailwind CSS v4 (#19846)
• Upgrade: never migrate files that are ignored by git (#19846)
• Add .env and .env.* to default ignored content files (#19846)
• Canonicalization: migrate overflow-ellipsis into text-ellipsis (#19849)
• Canonicalization: migrate start-full → inset-s-full, start-auto → inset-s-auto, start-px → inset-s-px, and start-<number> → inset-s-<number> as well as negative versions (#19849)
• Canonicalization: migrate end-full → inset-e-full, end-auto → inset-e-auto, end-px → inset-e-px, and end-<number> → inset-e-<number> as well as negative versions (#19849)
• Canonicalization: move the - sign inside the arbitrary value -left-[9rem] → left-[-9rem] (#19858)
• Canonicalization: move the - sign outside the arbitrary value ml-[calc(-1*var(--width))] → -ml-(--width) (#19858)
• Improve performance when scanning JSONL / NDJSON files (#19862)
• Support NODE_PATH environment variable in standalone CLI (#19617)

Added

• Support Vite 8 in @tailwindcss/vite (#19790)

Fixed

• Don't crash when candidates contain prototype properties like row-constructor (#19725)
• Canonicalize calc(var(--spacing)*…) expressions into --spacing(…) (#19769)
• Fix crash in canonicalization step when handling utilities containing @property at-rules (e.g. shadow-sm border) (#19727)
• Skip full reload for server only modules scanned by client CSS when using @tailwindcss/vite (#19745)
• Improve canonicalization for bare values exceeding default spacing scale suggestions (e.g. w-1234 h-1234 → size-1234) (#19809)
• Fix canonicalization resulting in empty list (e.g. w-5 h-5 size-5 → '' instead of size-5) (#19812)

Fixed

• Allow trailing dash in functional utility names for backwards compatibility (#19696)
• Properly detect classes containing . characters within curly braces in MDX files (#19711)

Added

• Add mauve, olive, mist, and taupe color palettes to the default theme (#19627)
• Add @tailwindcss/webpack package to run Tailwind CSS as a webpack plugin (#19610)
• Add pbs-* and pbe-* utilities for padding-block-start and padding-block-end (#19601)
• Add mbs-* and mbe-* utilities for margin-block-start and margin-block-end (#19601)
• Add scroll-pbs-* and scroll-pbe-* utilities for scroll-padding-block-start and scroll-padding-block-end (#19601)
• Add scroll-mbs-* and scroll-mbe-* utilities for scroll-margin-block-start and scroll-margin-block-end (#19601)
• Add border-bs-* and border-be-* utilities for border-block-start and border-block-end (#19601)
• Add inline-*, min-inline-*, max-inline-* utilities for inline-size, min-inline-size, and max-inline-size (#19612)
• Add block-*, min-block-*, max-block-* utilities for block-size, min-block-size, and max-block-size (#19612)
• Add inset-s-*, inset-e-*, inset-bs-*, inset-be-* utilities for inset-inline-start, inset-inline-end, inset-block-start, and inset-block-end (#19613)
• Add font-features-* utility for font-feature-settings (#19623)

Fixed

• Prevent double @supports wrapper for color-mix values (#19450)
• Allow whitespace around @source inline() argument (#19461)
• Emit comment when source maps are saved to files when using @tailwindcss/cli (#19447)
• Detect utilities containing capital letters followed by numbers (#19465)
• Fix class extraction for Rails' strict locals (#19525)
• Align @utility name validation with Oxide scanner rules (#19524)
• Fix infinite loop when using @variant inside @custom-variant (#19633)
• Allow multiples of .25 in aspect-* fractions (e.g. aspect-8.5/11) (#19688)
• Ensure changes to external files listed via @source trigger a full page reload when using @tailwindcss/vite (#19670)
• Improve performance of Oxide scanner in bigger projects by reducing file system walks (#19632)
• Ensure import aliases in Astro v5 work without crashing when using @tailwindcss/vite (#19677)
• Allow escape characters in @utility names to improve support with formatters such as Biome (#19626)
• Fix incorrect canonicalization results when canonicalizing multiple times (#19675)
• Add .jj to default ignored content directories (#19687)

Deprecated

• Deprecate start-* and end-* utilities in favor of inset-s-* and inset-e-* utilities (#19613)

Fixed

• Ensure validation of source(…) happens relative to the file it is in (#19274)
• Include filename and line numbers in CSS parse errors (#19282)
• Skip comments in Ruby files when checking for class names (#19243)
• Skip over arbitrary property utilities with a top-level ! in the value (#19243)
• Support environment API in @tailwindcss/vite (#18970)
• Preserve case of theme keys from JS configs and plugins (#19337)
• Write source maps correctly on the CLI when using --watch (#19373)
• Handle special defaults (like ringColor.DEFAULT) in JS configs (#19348)
• Improve backwards compatibility for content theme key from JS configs (#19381)
• Upgrade: Handle future and experimental config keys (#19344)
• Try to canonicalize any arbitrary utility to a bare value (#19379)
• Validate candidates similarly to Oxide (#19397)
• Canonicalization: combine text-* and leading-* classes (#19396)
• Correctly handle duplicate CLI arguments (#19416)
• Don’t emit color-mix fallback rules inside @keyframes (#19419)
• CLI: Don't hang when output is /dev/stdout (#19421)