Custom theme variables not working in media queries for custom variants #17840
Description
What version of Tailwind CSS are you using?
v4.1.5
What build tool (or framework if it abstracts the build tool) are you using?
Tailwind Play
What version of Node.js are you using?
Tailwind Play
What browser are you using?
Firefox, Chrome
What operating system are you using?
Ubuntu
Reproduction URL
https://play.tailwindcss.com/IeRkVmIgty?file=css
Describe your issue
In the linked reproduction, when the viewport is smaller than the md breakpoint, both the square and the circle should change colors. But only the square is working.
I am defining two custom variants using exactly the same syntax, but it doesn't work with my custom variable (--breakpoint-custom), though it does with a built-in variable (--breakpoint-md).
I have defined my custom variable under @theme, so I think it should work.