source: https://github.com/tailwindlabs/tailwindcss/pull/13395#issuecomment-2312747557 > [...] in v4, it will be `max-w-[var(--breakpoint-sm)]` as the shorthand arbitrary variable syntax will no longer be supported. > > `property-[--var-ref]` ➞ `property-[var(--var-ref)]` > > Related: > > * [Remove automatic `var(…)` injection #13537](https://github.com/tailwindlabs/tailwindcss/pull/13537) > * [Remove automatic `var(…)` injection #13657](https://github.com/tailwindlabs/tailwindcss/pull/13657) > * [Disable automatic `var()` injection for anchor properties #13826](https://github.com/tailwindlabs/tailwindcss/pull/13826) > > [...]