Why did the ancients call the four seasons youth, Zhu Ming, autumn and summer?

On the Volume: "Spring is Qingyang, summer is Zhu Ming, autumn is Bai Zang, and winter is Xuan Ying."

The name of the suburban worship song in Han Dynasty. Historical Records: Qingyang, Xia Song, Hao, Xuanming Winter Song.

Spring and winter are named according to the solar terms. Therefore, it is called youth and dark winter. Zhu Ming in summer. As for autumn, whether it is "Bai Zang" or "Xiqiao", it is a bright moon, so it is called Su Qiu.