[plugin:vite:css] [postcss] /Users/innei/git/innei-repo/linear/src/styles/index.css:3490:14: Unknown word

When using tailwindcss v4, a postcss error occurred. Inspection revealed that the issue was caused by this class name.

  .size-\[\$\{iconSize\}px\] {
    width: ${iconSize}px;
    height: ${iconSize}px;
  }