Current Minerva skin is purposely restricted to 55.8em
This means references will never be split into 2 columns as 30em*2=60em.
Dropping it to 25em would mean the CSS applies here and no more than 2
columns would ever be used to display references.
Bug: T160497
Change-Id: I6f9b85cd6cfdb055692b1f537d569c158900f7c9
