Arbitrary Variants looks a bit crazy to me (I haven't used it yet though): https://github.com/tailwindlabs/tailwindcss/pull/8299
It'll be really nice for container queries when they're ready. Something like: `wider-than-[500px]:hover:text-red-500` and so on.
Also super nice for `:has` (although ordering is a concern at the moment): `[:has(:invalid)]:bg-red-500`.