[Redesign] Home nav normalization
Summary: Ref T8099, makes the home nav elements more resilient to font size changes, fixes alignment on mobile.
Test Plan: Review home nav with smaller and larger font, check hover states, check phone layouts.
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: epriestley, Korvin
Maniphest Tasks: T8099
Differential Revision: https://secure.phabricator.com/D13465