Pioneering fashion rule-breaker Bill Blass, who set new standards for American style by mixing and matching chic with casual, died Wednesday at his home in Washington, Conn. He was 79. According to reports, the cause of death was cancer. Blass's clients included former first ladies Nancy Reagan and Barbara Bush, as well as Barbara Walters, Barbra Streisand and Candice Bergen. "I love his clothes, because they are comfortable, wearable and pretty," Reagan once said. Blass — who said he designed for women "not obsessed with fashion" — went on to expand his $700-million-a-year empire to include men's wear, swimwear, children's clothing, shoes, jewelry and furs.