I’m not sure if there’s a setting for this, but I use dark and gray mode (depending on my mood). So the background is dark and my text is white.
Normally, if I do a text-selection, the highlight becomes black or dark-gray, and my text becomes yellow. That’s perfect.
However, when I do a search, Scrivener highlights the search-term in the main-editor with YELLOW. Which makes the white-colored text unreadable.