Add a more specific CSS rule to make Spaces headers in projects colored red

Summary:
Depends on D19551. Ref T13164. Projects use a special kind of header setup that has a more specific CSS rule to make content black. Add an even more specific rule to make it red.

(This could probably be disentangled a bit and isn't necessarily the cleanest fix, but I poked at it for a few minutes and didn't come up with anything cleaner.)

Test Plan: Viewed projects in spaces, saw the space names colored red properly.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13164

Differential Revision: https://secure.phabricator.com/D19552