Tween bedrooms ideas...?

Right so my younger cousin is having her bedroom decorated. I offered to help her mum and my mum is helping aswell. At the moment she has a lilac carpet with 2 walls pink and the other 2 purple. She wants to have a nice bedroom that will look nice. We were thinking about a hot pink carpet with beige/ powder white walls with a border round the room. But wern't sure about a white wall what other colours would go with a hot pink carpet and what type of furniture? (she is nearly 12)