US Democratic presidential candidate Kamala Harris has vowed to fight hard in the final stretch of the campaign, urging her party to brace for a “tight race” against Republican Donald Trump as she addressed supporters at a rally in Milwaukee, Wisconsin. “We know this is going to be a tight race until the very end. We have hard work ahead of us, but we like hard work. Hard work is good work,” Harris said on Tuesday evening. “No, no, we haven’t already won,” the 59-year-old continued, responding to shouts from the audience. “We have 77 days of work to do,” she said. Although Harris is slightly a…