New CSS @apply rule causes crash

[nektro]

The new CSS @apply rule decribed here causes a crash.

events.js:141
      throw er; // Unhandled 'error' event
      ^
 Error: C:\GitHubWeb\CssMaterial\src\components\button.css:17:5: missing '}'
    at error (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\node_modules\rework\node_modules\css\lib\parse\index.js:62:15)
    at declarations (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\node_modules\rework\node_modules\css\lib\parse\index.js:259:26)
    at rule (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\node_modules\rework\node_modules\css\lib\parse\index.js:560:21)
    at rules (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\node_modules\rework\node_modules\css\lib\parse\index.js:117:70)
    at stylesheet (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\node_modules\rework\node_modules\css\lib\parse\index.js:81:21)
    at module.exports (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\node_modules\rework\node_modules\css\lib\parse\index.js:564:20)
    at rework (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\node_modules\rework\index.js:27:21)
    at DestroyableTransform._transform (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\index.js:82:22)
    at DestroyableTransform.Transform._read (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\node_modules\through2\node_modules\readable-stream\lib\_stream_transform.js:184:10)
    at DestroyableTransform.Transform._write (C:\GitHubWeb\CssMaterial\node_modules\gulp-concat-css\node_modules\through2\node_modules\readable-stream\lib\_stream_transform.js:172:12)

The referenced file can be found here.

Although not technically standard CSS, it has already shipped in Chrome and Opera.

[arbaev]

The same problem with @media and so on.