I found that switching my Edge browser's light/dark mode is also switching it for the Word Web App.

I've already set light mode on the Office.com landing page and Office.com becomes light, but the individual Word Web App seem to listen only to the local Edge setting.

All others that I've tested:

Excel/PowerPoint: seems to have dark mode yet

Outlook/OneNote: switchable through the top-right settings cogwheel, just like the Office.com landing page

So it really seems that other apps with the dark mode ability, are switchable on a per-app basis, but Word doesn't have that 'top-right settings cogwheel'-option and only listens to the local MS Edge setting.

Am I missing something?