R1:800b3b030f1c

Basic style for exception page

Summary: Fixes T6846, cleans up spacing, makes it look scary red.

Test Plan: Fake an exception, see new layout

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6846

Differential Revision: https://secure.phabricator.com/D11161