Why have US-China relations chilled so much and so quickly that it looks like a new Cold War has begun?

It was not so long ago that the world, including the United States, welcomed China's rise within the international global order. It was seen as mutually beneficial - the liberal economic system would gain from the entry of 1.3 billion people into its fold, and, in turn, China benefited greatly as a member of the community, making unprecedented progress. It seemed win-win for all.