Svelte-check reports valid CSS properties such as corner-shape as unknown

[golmakov]

Describe the bug

The bundled vscode-css-languageservice is behind on modern CSS properties, so valid CSS such as corner-shape is reported as an unknown property.

Reproduction

Create any .svelte file with:

  <style>
        div {
                border-radius: 12px;
                corner-shape: superellipse(1.2);
        }
  </style>

svelte-check --tsconfig ./tsconfig.json reports:
Warn: Unknown property: 'corner-shape' (css)

Expected behaviour

corner-shape is a standard CSS property (Chrome/Edge 139), so no warning should be reported.

System Info

• OS: macOS 15.7.7
• IDE: Zed
• svelte-check 4.7.3 and 4.7.4, svelte 5.56.7, TypeScript 6.0.3

Which package is the issue about?

svelte-check

Additional Information, eg. Screenshots

Svelte-language-server declares vscode-css-languageservice: ~6.3.5 and vscode-css-languageservice 6.3.10 already knows corner-shape so bumping version should fix this