Dark-mode email preview

For school administrators using GiveCampus Outreach. Controls can differ between the classic email editor and the newer Composer editor.

The Outreach and Events email preview screens do not expose a dark-mode preview toggle. Use a test email opened in the intended email client with dark mode enabled to review the actual recipient appearance; the ordinary in-app preview is not a simulation of every email client. This applies to email preview, not a promise about a dark theme for the public event page.