Who uses it: Two sisters, ages 13 and 16Location:Pacific Heights neighborhood of San FranciscoSize: 100 square feet (9.3 square meters)Designers:Sabrina Alfin (interior design) and Stephen Verner of Verner Architects (architecture)Designer Sabrina Alfin was brought on to help select the finishes and decorate this renovated bathroom for two teenage girls in San Francisco. She came up with a transitional mix that features a hardworking vanity painted a striking French blue, a shower with classic white subway tile, and a floor made of mini mosaic herringbone tiles.The result is a classic bathroom that feels fresh and will remain stylish for many years to come.