Night mode issues, LibreOffice Writer

I recently got dual monitors, which has been a godsend for my workflow. However, I’m also slightly visually impaired, so I use the Microsoft Magnifier feature to invert text while I’m writing my PhD thesis, and the Magnifier feature doesn’t have an option to invert only a single screen. This means I’ve had to add invert colour features to individual programmes when one window needs colour inversion but the other does not, it’s very annoying.

So I’ve been trying to give LibreOffice a nightmode colour scheme for when I’m running a programme on my second monitor that shouldn’t be inverted, but I’m having a few difficulties. Going to LibreOffice → Appearance seems to only alter the colours around the margins, and not the text area itself. This is an issue primarily with my already existing thesis document, as it doesn’t happen for new documents.

But, I can’t for the life of me figure out how to make it so that the system colours override the document colours, and I’m not willing to change the document itself to white-on-black since it would be a hassle for when I need to submit it for other eyes.

Can someone help me out here?

If you don’t get an answer here, you also can try to send a mail to Users@Global.LibreOffice.Org. Make sure your receives these mail; you need to subscribe.

Note that LO uses system theme settings, so any effort to set a suitable night mode is likely best achieved by first making changes to the system theme. Also note that there are bugs in certain configurations e.g., fdo#50296.