x-team/wp-dependency-minification — pull request #60 by msigley (2014-06-04 16:44:59+00:00)
Title: Adds at-rule handling to CSS compression.

Properly handles charset, namespace, and import at-rules according to:
https://developer.mozilla.org/en-US/docs/Web/CSS/At-rule

Import rules are currently just stripped out of the CSS to prevent issues in the output, but this could be improved by including the contents of the import url and compressing it.