Why are the days long and the nights short in the northern hemisphere during the summer solstice?

This is a regression movement. On the solstice of summer, the sun shines directly on the Tropic of Cancer. This is the hottest day in the northern hemisphere. In this process, the sun from the equator to the tropic of cancer, the longer the day, the shorter. Speaking of the Tropic of Cancer, that is, the summer solstice, you can understand that it is the highest latitude of direct sunlight in the northern hemisphere, and this time is the longest day in the northern hemisphere.

I don't know if your teacher drew a picture for you, just talking about sports. You must understand it after reading that picture, but it is not convenient for me to draw a picture for you now. I hope you can understand why after reading what I said above.