$re = '/@import[ ]*[\'\"]{0,}(url\()*[\'\"]*([^;\'\"\)]*)[\'\"\)]*/i';
$str = '@import "font-awesome.min.css";
@import "simple-line-icons.css";
@import url(http://fonts.googleapis.com/css?family=Montserrat:700,400);
@import url(\'http://fonts.googleapis.com/css?family=ggg\');
@import url("http://fonts.googleapis.com/css?family=ggg");';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php