malformed css

line 15 of custom-ads/css/wdca-wpmu.css has a spurious ! mark which may be from a not-present !important flag, or may be erroneous. As it stands the css is flagged as invalid. For now I have removed the spurious ! mark to maintain the current behaviour. If the css _should_ include !important then please let me know.

This is just a heads-up so that a future release may include well-formed css.