Two decades after the UK handed it back to China, President Xi Jinping is in Hong Kong for the first time to celebrate the anniversary. The ‘one country, two systems’ principle was designed to preserve democratic freedoms in the wealthy former colony. After troubled years of protest at the perceived erosion of those rights, the Guardian meets young Hong Kong citizens struggling to afford property, those moving abroad for opportunities, leaders of the pro-democracy umbrella movement and movers in the pro-Beijing establishment.