How to change side menu header title & subtitle text color?

[AdCreative_Art (AdCreativeDev)]

Side Menu Layout Header Title Text Color?

I see myself at the end of a long search process and get nowhere. The most important thing: A) The header title text is white. I want to change it, but how? B) Where do I get themes for the Side Menu Layout Component? @Boban has talked about it in a thread, but nobody has written anything informative about it. (I know, better to use a custom one, but for now it’s enough)