The biggest, loudest sports party that Philadelphia had thrown in nearly a decade looked and sounded like this Sunday night: people wearing green shirts and dog masks screaming and whooping until their lungs burned and the building shook, a journeyman defensive back intercepting a pass and weaving from one side of the field to the other before slipping into the end zone and dashing down a tunnel, a head coach calling daring plays without fear against the best defense in the National Football League, a backup quarterback flinging deep passes to wide-open receivers and threading passes to less-open ones, a city that has never celebrated a Super Bowl victory now alive and thrumming with what might yet be.