I think he is referring to Email when opening Office 365 (NOT the Web App). It allows you to select a theme, but that only changes a small strip at the top of your inbox. The body of Outlook has a white backgrough, which can cget very harsh for people to read, especially in an office setting where you're looking at it ALL day. The does not seem to be any way to select a different backgroud (even black would be great). Searching the internet keeps coming back to Office 2013, not 365. Its seems like a no brainer that this option should be available in 365 but it is not - unless we're missing something.