Re: Outlook, the last bastion of weird customization hackery
You can change your theme between Colorful, Gray, White and Black
Don't know what version of Outlook you're running, but here (Office 2016) I only have a choice of Colorful, Dark Gray or White.
I'd love to have an option of Black, which work better for my (far from youthful!) eyes ... but then again, my personal preference is for yellow text on a navy background!