I no idea who or why Microsoft would change how a user sees their software interface without any warning or permission. Yet, it has happened recently. A user had their office changed to Dark Mode. For example of Dark Mode, See Image 3.
Fortunately, it is fairly simple to change the Office Mode. From within any Office application, click File from the main menu. The example here is from Word.
Click
Account from File Menu.
There are two controls.
1. Office Background
2. Office Theme
The Office Background Control displays a number of different decorations
to adorn your Office apps.
I am very boring. I have
no background. Any change to what I expect my interface is
supposed to look like makes me very nervous.
The Office Theme Control changes how Office Apps look. The example here is Black, also known as Dark Mode.
The Office Theme has a variety of themes. The most common is Same as System.
I
find it ironic that certain people today find Dark Mode appealing.
In the early days of computing the default was white pixels on a black screen. The came 16 colors; and the 256 colors; and now millions of colors.
Black and white has never looked so good. If that's your thing.