Summary:
Ref T988. Fixes T3150. I want to use this element in Diviner, so separate it from Phriction.
This makes no changes to the actual display except for fixing {T3150} by adding `overflow: hidden;`.
Test Plan: Viewed Phriction documents in mobile and desktop views.
Reviewers: chad, btrahan
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T988, T3150
Differential Revision: https://secure.phabricator.com/D6101
