Frank Lloyd Wright’s distinctive Marin Civic Center building hosts more than 600 marriages a year, serving as a unique backdrop for couples who are joined in matrimony by a deputy county clerk for a fee of $56. The betrothed may have their civil ceremony in several spots in the building. Most opt for the compact garden off the second-floor cafeteria, where a bubbling fountain provides a natural sound track and the Civic Center’s soaring golden spire offers inspiration. That’s where San Rafael’s Raphael Barker and Keri Syndulko exchanged vows during a rainy afternoon in December.