Helen Gurley Brown loved pink so much, the color graced the silk-covered walls of her office at the Hearst Tower. In memory of the late Cosmopolitan editor, the atrium lobby is bathed in pink light this week, including the three-story water sculpture, “Icefall.” Brown — whose motto was, “Good girls go to heaven, bad girls go everywhere” — came into work nearly every day until her death Monday at 90, staffers said. She was editor of Cosmo from 1965 to 1997, then oversaw the magazine’s international editions and maintained her pink office with leopard-print carpeting. The setup originally existed at Cosmo’s old offices and was re-created when Hearst’s HQ was redone. A memorial service is planned for the fall.