Colorado’s first-in-the-nation experiment has reshaped health, politics, rural culture and criminal justice in surprising ways that often defy both the worst warnings of critics and blue-sky rhetoric of the marijuana industry, giving a glimpse of what the future may hold as more and more states adopt and debate full legalization. Some families rattled by their children’s marijuana problems have moved, seeking refuge in less permissive states. But over all, state surveys do not show an increase in young people smoking pot. And while low-level marijuana charges have plummeted, the racial divide in drug arrests has persisted.