Warner Bros.When Barbie production designer Sarah Greenwood and set decorator Katie Spencer first set out to create Margot Robbie’s Malibu mansion, they were coming into the world as fresh as, well, Barbie herself. They’d never owned one of the dolls or her Dream House. Their first inspiration was director Greta Gerwig’s script, and then came their shared love for vintage Americana—its simplicity and joy, as applied to a pink, toyetic wonderland. They based their paradise on the great dream hous