Nth-child with spaces inside gets broken

[roby65]

We have this code in our css:

nth-child(1 of :not([class*=hero]))

This gets minified to:

nth-child(1of :not([class*=hero]))

Breaking it.

The code that breaks this is in CSS.PHP line 757:

$content = preg_replace('/:(' . implode('|', $pseudos) . ')\(\s*([+-]?)\s*(.+?)\s*([+-]?)\s*(.*?)\s*\)/', ':$1($2$3$4$5)', $content);