Arbitrary Responsive Design Breakpoints failing?

[karlhorky]

What version of Tailwind CSS are you using?

v4.1.18

What build tool (or framework if it abstracts the build tool) are you using?

Next.js 16.1.0

What version of Node.js are you using?

v24.11.0

What browser are you using?

Chrome

What operating system are you using?

macOS

Reproduction URL

https://play.tailwindcss.com/CuIexr8MvB

Describe your issue

The @min-[<number>px]:<utility> syntax documented on Responsive Design: Using arbitrary values appears to be broken with Tailwind CSS v4.1.18 - I would expect a red background: