She's beautiful (he looks pretty dapper too!) and I really love the color of her dress! Is his tux navy blue? I can't tell too well from the photo but I think the ribbon in her corsage is blue?
These are the kits that came to mind when I tried to think of matching colors (but not necessarily theme) for it:
Pinks and Blues:
or Pinks and Blacks:
And if you're the type to kit mix Flergs has this kit that has a lot of pretty navy blues you could mix with the right color pink from another kit: