Update side counters to blue, inset.

Summary: Changes the side number counts to blue with a subtle inset, less straining on the eyes, yet very visible.

Test Plan: Tested short and long numbers in wide and normal button areas. FF, Chrome

Reviewers: epriestley, vrana, btrahan

Reviewed By: vrana

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4513