R1:c9e2df679901

[redesign] Hoverselect colors

Summary: Builds a consistent 'selected, hover' state slightly darker than selected states.

Test Plan: Tested Conpherence, Sidenavs

Reviewers: epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9345