Why is Qin Shihuang's robes black? What made him choose this color?

During the Qin and Han dynasties, due to the unification of the country, clothing styles tended to be consistent. The Qin Dynasty was the first feudal unified country with vast territory and numerous nationalities in the history of China. After Qin became Qin Shihuang, he immediately began to implement a series of measures to strengthen centralization, such as unified measurement and criminal laws and regulations. , including clothing and clothing systems. However, due to Qin Shihuang's short ruling time, the clothing system was only preliminary and incomplete. Only the color of the clothes is unified. Qin Shihuang was deeply influenced by the theory of Yin-Yang and Five Elements. I believe that Qin Zhouke should be fire and water, because the Zhou Dynasty was "fire is better than gold, and color is better than red", so Qin Shengzhou is a water virtue, and color advocates black. In this way, in the Qin Dynasty, black was a noble color, and clothing was also a fashionable color.