So I use automatic dark mode switching in Zorin OS and it works awesome. LibreOffice seems to follow the same automatic switching which is a nice feat but it looks just horrible, black background with black text. Sure I could switch it off manually or set the text to white but that would imply reverting everything when theme goes to light.
To be precise, the font color should really behave automatic (it IS set as automatic) but it doesn't. It is related to LibreOffice, not Zorin, but maybe someone has a workaround.
A bit of searching turned up that this is an issue with LibreOffice's standard theme. To fix it, install some other theme from the very options menu you screenshotted, select it, and then instead of system, choose Dark. You'll likely get a white document background, which probably isn't what you want, but you can manually set the document background color and grid color, and get automatic font color that's not screwed up. Existing documents may have the bad colors saved into them, I'm finding, so hopefully this isn't a major loss of work to you.
Finally, there were comments that it may require resetting your user profile.
Yeah, thanks for the reply. It is not a big deal, but it is an obvious bug in Libre Office.
It is, and it's annoying. Present in Windows versions, too. Hopefully they'll fix it before long.
Did You take a Look in the Quick Settings if the Toggle for Dark Mode is on?
Where in quick settings?
See the red marked Button. Ignore the Language; my System is in German. You should have that, too. You come to this when You click in the Taskbar on the Indicators for Sound, Web etc.:
Sure, I have specifically toogled on the dark mode and it functions properly. That is the reason why LibreOffice changes theme, as it is set to automatic.
Just changed my desktop to dark mode and no issues:
I opened LibreOffice settings, Appearance, Themes then Font - Font was showing black but output on screen was white - then changed Font to White and still White font in spreadsheet. Try changing Font from Black to White.
I only ask because of the Font Color. Does Your System run in Wayland or X11? You can check that in Settings>About.
Switching the font color surely works, but it kinda contradicts the whole point of automatic theme switching, especially when the text color again needs to be changed to black when the theme goes to light.
Wayland