Black instead of white font color and icons, how to change?

Hello,

I just set a background and right after that my Nextcloud changed the font colors and the color of the used icons to black. I would like to change it back because white was looking way better and was better to read.

I just recognized that Nextcloud seems to change the font color depending on the color set in the design settings - if I change the color, it switches but unfortunately to black instead of white.

I also tried the app “Custom CSS” but had no real luck to change that. Anybody got an advice how to change the font color and the used icons?

I am currently using version 28.0.4 (Community)

Thank you!