Build error with tailwindcss 4.x

Hello

Homebrew maintainer here. We would like to rebuild oranda with tailwindcss 4.x
Here is the error:

```
==> cargo install
Last 15 lines from /Users/michkapopoff/Library/Logs/Homebrew/oranda/01.cargo:
-o, --output ·········· Output file [default: `-`]
-w, --watch ··········· Watch for changes and rebuild as needed
-m, --minify ·········· Optimize and minify the output
--optimize ········ Optimize the output without minifying
--cwd ············· The current working directory [default: `.`]
-h, --help ············ Display usage information

--- stderr
Error: Can't resolve 'variables.css' in '/private/tmp/oranda-20250202-52773-so86i6/oranda-0.6.5/oranda-css/css'
thread 'main' panicked at generate-css/src/lib.rs:53:10:
Tailwind failed to compile CSS!
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
error: failed to compile `oranda v0.6.5 (/private/tmp/oranda-20250202-52773-so86i6/oranda-0.6.5)`, intermediate artifacts can be found at `/private/tmp/oranda-20250202-52773-so86i6/oranda-0.6.5/target`.
To reuse those artifacts with a future compilation, set the environment variable `CARGO_TARGET_DIR` to that path.
```

Can you have a look?