A Test which indicates that the gHorizontalPercentageRegExp Regexp is too greedy and a fix for the pattern which might not be optimal
See http://core.trac.wordpress.org/ticket/26181
Prevent issues with css selectors containing parentheses

See https://code.google.com/p/cssjanus/issues/detail?id=22

This has already fixed in MediaWiki php port -
https://doc.wikimedia.org/mediawiki-core/master/php/html/CSSJanus_8php_s
ource.html