Swap Source Sans Bold for Semibold
Summary: Testing this out, feels much less heavy and more readable for me, but open to other feedback. I've also corrected/normalize the header sizes and heights.
Copied some real Phriction documents to my local install, read them all. Checked header sizes and make sure px are used for more absolute control over sizes.
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T7963
Differential Revision: https://secure.phabricator.com/D12587