Bug: CSS descriptor "unicode-range" causes runtime error with rule "css/no-invalid-at-rules"

[Otlikov]

Environment

ESLint version: 9.31.0
@eslint/css version: 0.10.0
@eslint/css-tree version: 3.6.1
Node version: 24.4.0
npm version: 11.4.2
Operating System: macOS 15.5 (24F74)

What did you do?

Ran eslint with @eslint/css on the following code

/* eslint css/css/no-invalid-at-rules: ["error"] */

@font-face {
    font-family: 'myFont';
    src: url(./myFont.woff2) format('woff2');
    unicode-range: U+00, U+0D;
}

What did you expect to happen?

CSS descriptor "unicode-range" should be handled properly.

What actually happened?

Runtime error occured with:

Oops! Something went wrong! :(

ESLint: 9.31.0

Error: Bad syntax reference: <unicode-range-token>
Occurred while linting...

[xbinaryx]

I can reproduce this. It looks like csstree hasn't implemented <unicode-range-token> yet. See: csstree#333 (comment). In the meantime, reverting #26 no longer causes ESLint to crash. I’ll wait for the team’s feedback before proceeding further.

[nzakas]

Let's revert #26 for now, but leave this open to look for a more permanent solution.

[nzakas]

I'll revert the PR.

[eslint-github-bot]

👋 Hi! This issue is being addressed in pull request #79. Thanks, @Copilot!