Hygiene: Update site CSS fixture
Hygiene: Update site CSS fixture

Due to https://en.wikipedia.org/w/index.php?title=MediaWiki%3AMobile.css&type=revision&diff=881305659&oldid=867579901

Change-Id: I98e756342f4058b3b346e2ec64a5e3d2c8eef48a

wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps