While apps like Word, Excel and Access all have a dark theme for the UI, however, it is rendered quite ineffective considering its intentions (to reduce eyestrain). The main focus of these apps is the content in the middle of the screen (whether it be a spreadsheet or a document) so when I enable dark theme and the largest part of the screen is still bright white, it makes me wonder why I would use it in the first place.
In OneNote, Microsoft has done a great job at including a 'dark mode' and this is what I'd like to see in Word, Excel etc. where the dark mode includes the background and inverts the text along with brightness of the pens while keeping photos and other attachments in their original forms:
This can be as simple as a 'Switch Background' button in the ribbon (like in OneNote).
I'm a student who suffers from severe photophobia due to albinism and this feature would allow me personally to use word without eyestrain and fatigue while still keeping the document accessible to other people who want to view, share or print it. It would make my workflow less complex as I would no longer need to invert the colours of the entire screen through Ctrl + Win + C over and over again and would definitely allow me to focus more on my classes and be a better student.
I know, and I do that. The problem is, I have to change it back before I go to send it to a colleague, or before I print it. Also, various elements such as tables and borders don't change colour, they stay black - rendering them invisible. I believe a quick "change background" button would resolve all this - just like the one in OneNote.
This is a great idea and I would suggest that you submit this feedback in the apps you'd like to see this implemented in by going to Help > Feedback. In the meantime, the workaround you've been using is the best available option at this time.