cdn not set for CSS loaded with @import

On my theme, most of the CSS is loaded using @import:
@import "/sites/all/modules/admin_menu/admin_menu.css?y";
@import "/modules/aggregator/aggregator.css?y";
@import "/modules/node/node.css?y";
@import "/modules/system/defaults.css?y";
@import "/modules/system/system.css?y";
@import "/modules/system/system-menus.css?y";
@import "/modules/user/user.css?y";

I don't have time to create a patch but I fixed it by modifying parallel_preprocess_page()
and adding

$variables['styles'] = str_replace(' href="/', ' href="' . variable_get('parallel_domain_css', '') . '/', $variables['styles']);
//fix for @import
$variables['styles'] = str_replace('@import "/', '@import "' . variable_get('parallel_domain_css', '') . '/', $variables['styles']);