Revamp .device Conpherence layouts

Summary: Greatly improves the text area and cleans up spacing and color issues.

Test Plan:
test Conpherence at desktop, mobile, tablet break points. Test new flexible layouts.

{F372516}

Reviewers: epriestley, btrahan

Reviewed By: btrahan

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D12431