More minor CSS tweaks globally

Summary: Moves profile/project to use more standard colored boxes. Reverts dashboard border colors. Ensures better High-Contrast application more consistently across these projects. Also fix T12211.

Test Plan: Home, People, Projects in High Contrast / Standard

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T12211

Differential Revision: https://secure.phabricator.com/D17321