Here’s a really quick tip on how to deal with replying to emails that have an annoying background color.
Don’t change your font-color to white so it shows up on that black background. Just remove the background color! (This works for Outlook 2013 and 2010.)
After you’ve hit “Reply” to the offending email, go to Options on the Ribbon.
Under Themes on the left of the Ribbon, click on the down arrow next to Page Color, and select “none” (or “white”).
You’ve just saved yourself and the recipient, and anyone else in a string of future emails, from getting a headache.