Tailwind CSS v4.1.18

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog,
and this project adheres to Semantic Versioning.

[Unreleased]

• Nothing yet!

[4.1.18] - 2025-12-11

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)

Added

• Experimental: Add @container-size utility (#18901)

[3.4.19] - 2025-12-10

Fixed

• Don’t break sibling-*() functions when used inside calc(…) (#19335)

[4.1.17] - 2025-11-06

Fixed

• Substitute @variant inside legacy JS APIs (#19263)
• Prevent occasional crash on Windows when loaded into a worker thread (#19242)

[4.1.16] - 2025-10-23