Sorry, I meant the “pdf.css” which has @media print CSS - no matter, what I do with this file, it does not change the exported PDF at all. I even completely deleted it to see, what happens. The toggle under appearance for this CSS-file also makes no difference. Also it sometimes switches on again by itself after toggling it off. So where exactly can I modify the CSS for the PDF-export now?
Edit: I asked for a way to override, because it reads “always export with light theme” and then the above happened. If I understand you right, it can be overridden, now I am just not sure where to make the changes as I have not been successful so far.
I found, that @media print in my case - whyever that may be - did not work. However, changing the styles in the pdf.css so that each tag or class was inside a .print class (without using a media query at all) did work.