The methods mentioned here let you disable the Grey theme too.
On Windows, you get a lighter version of the black theme known as Dark Grey. The proper dark or black theme is limited to Office 365 subscribers only. In this post, we will tell you how to get rid or turn off the dark mode in Microsoft Word, Excel, and PowerPoint on Windows and macOS. Fortunately, when an app or a tool introduces the dark mode, they give us the ability to disable it too. And I’m pretty sure many others like me don’t like the black or dark mode.
