Increase specificity in blue property boxes

Summary: Feels a little hairy, but should be fine overall. Ups the css specificity enough that it's always displayed the same. The main problem is headers and boxes get put everywhere, and sometimes override each other. Fixes T10757

Test Plan: review a countdown in a phame post and phriction document. Check diviner, phriction for regressions.

Reviewers: epriestley, Phacility

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T10757

Differential Revision: https://secure.phabricator.com/D15664