In my dictionary, variant forms appear in parentheses after the headword. When I change to the black background color scheme, the variant forms disappear. I’m assuming the text is still black instead of turning to white. This happens on iOS and on Android.
I guess this is related to other problems concerning the black background colour theme. I have it currently disabled in our app since there are too many problems, would be great to have it back, it’s what many young people prefer, isn’t it?
I guess theoretically that could be modified manually in the color scheme. (Obviously it would be better if the default were correct…) Have you tried to identify that style in the color scheme, and it doesn’t exist? I.e. the style that would control the text color of that item in the dark color scheme is not in the list? Being able to add a custom style may be able to take care of that… I think that might be a feature request already.
I don’t know how to identify the style that applies to variants.