User blog comment:Brandon Rhea/Introducing Unification, FANDOM's next big initiative/@comment-8072-20181004022655/@comment-26437440-20181004094452

Given the focus on mobile/apps lately which show little to no theme styles...I'm guessing it might include ways to customize the mobile view, albeit with many restrictions.

New Wikia features seem to be either completely non-customizable or can only be changed in small ways (like the header and discussions), so I don't have high hopes for potential customization in whatever unification is.