MacOS
node -v: v21.7.3
Tailwind v4.2
Tailwind installed via homebrew
Notes: I already upgraded, restarted, etc.. it only happens with the new colors (taupe,...)

Command:
tailwindcss -i ./resources/css/backend.css -o ./public/assets/css/backend.css --watch
≈ tailwindcss v4.2.0
Done in 288ms
Error: Cannot apply unknown utility class bg-taupe-500

CSS Class in external file external-classes.css

@utility color-taupe {	@apply bg-taupe-500 text-white; } 

Main CSS file

@import "tailwindcss"; @import "../css/external-classes.css";