Apple - How can I remove 'Dark Mode' from Ms Office apps without disabling it across macOS?

To disable Dark Mode for MS Office only, you need to run a terminal command for each of the MS Office apps in question.

For example, if you wish to disable dark mode in MS Excel, follow these steps:

1. Quit Excel if it’s running
2. Launch Terminal (usually found in the Applications/Utilities folder)
3. Enter (or copy and paste) the following command: defaults write com.microsoft.Excel NSRequiresAquaSystemAppearance -bool yes
4. Now press return
5. Enter (or copy and paste) the following command: killall cfprefsd
6. Now press return

Now when you launch MS Excel it should appear as it it normally would without Dark Mode enabled.

NOTES:

• To do this with the other MS Office apps, just change the command at Step 3 so that it’s referencing the app in question.
• Each of the app names within the command must start with an uppercase letter (note the uppercase 'E' for Excel in the command at Step 3.
• For PowerPoint, the app name must be spelt as follows: Powerpoint (i.e. only the first P is in uppercase, not both Ps)
• To revert back to Dark Mode, follow the same steps but end the command at Step 3 with no instead of yes.