Add changelog

Author: philipp-spiess

CHANGELOG.md

@@ -7,7 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-- Nothing yet!
+### Fixed
+
+- Ensure the `color-mix(…)` polyfill creates fallbacks for theme variables that reference other theme variables ([#17562](https://github.com/tailwindlabs/tailwindcss/pull/17562))
 
 ## [4.1.2] - 2025-04-03