ANN structure of CSNet. The structure consists of a scalable, five-layered feed-forward network. The input layer imports the 13 stellar colours transformed by J-PLUS DR1 and Gaia DR2 after extinction correction as the basic features. The following three hidden layers with activation functions extract the deep nonlinear features of the stellar colours. The output layer provides a stellar label with a weighted sum of the learned features in the last hidden layer.