if you're hoping she might follow your wiccan path, but she wants "dark or black", maybe if she looks at other types of pagan religions - some which are more "left hand path" than wicca (which is "right hand path"). Get her to look into santeria. Or if she wants to go down the Set or Satanist path, let her research it properly - it isn't "anti christian". Yes Lucifer is a fallen god, his sister is Diana.

Let her learn about balance and duality, that there must be a balance in the world, that there are "dark" and "light" sides to everything.

Why don't you bring some ritual into your home, do some research on "kitchen witchery" and let her start to do some of that.

Much as I don't like this person, Fiona Horne's first book isn't bad for a general look at things.

I can put her in contact with a good friend who is a satanist, she can ask her questions. Or I can get you in touch with Jess (my friend) to ask questions. Jess is wonderful, she is a mum, so is very wary of the type of information out there on her religion and will happily guide somebody in the right direction with information gathering etc.