Error with relative import in css file

[thanhnambkhn]

Hi,
When minifying with iCheck css on my Asset (such as:

public $css = [
        'themes/adminlte/plugins/iCheck/all.css',
..];

I get that error:
file_get_contents(.../web/web/themes/adminlte/plugins/iCheck/minimal/_all.css): failed to open stream: No such file or directory

When I open all.css file, I found that line at the very first:

/* iCheck plugin skins
----------------------------------- */
@import url("minimal/_all.css");