Touch up Pholio

Summary: Uses common CSS spacing, tweaks some colors, increases viewport size to very limits.

Test Plan:
Test large and small images, various breakpoints. Able to more easily review mocks.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9534