Why does Kant reject the existence of God in pure reason and admit the existence of God in practical reason?

Kant can neither prove his existence nor prove his non-existence. The argument he made only wanted to make his own voice, and those who demonstrated the existence or non-existence of God were also based on this reason. Three human instincts: competition, survival and reproduction. Their opinions are essentially driven by competitive instinct, and if they are recognized, they will be in a favorable position in resource competition. The so-called argument simply does not hold water. To tell the truth, some people can't even explain what their own thinking consciousness is, and then explain the world, which can be regarded as a joke in itself.