Compilation error messages in the plus-loader css file

[isometriq]

I've installed using bower. It worked well, but errors are showing up in body:before {}

It is coming from the following file
bower_components/css-spinners/css/spinner/plus-loader.css

[isometriq]

Reference:
https://github.com/jlong/css-spinners/blob/master/css/spinner/plus-loader.css