First of all, as far as "men want handsome soap" is concerned, the ancients believed that men, as the pillars of the family, needed to establish a mature and stable image. Dark clothes can just help them increase their sense of stability, while light clothes will make them look a little frivolous. At the same time, in ancient China, men cultivated land and women wove, and men often had to work in the fields or do other heavy work. In the process of doing these things, their clothes get dirty easily, while dark clothes are relatively resistant to dirt.
Let's look at "women should be beautiful and filial", which can actually be seen in many film and television dramas. For example, the little dragon girl in "The Condor Heroes" and Wang Yuyan in "Eight Dragons" are both dressed in light colors, and their roles are also "fairy".
On the contrary, many enchanting and vicious female characters often wear red and black clothes. After the ancients formed such a dress aesthetic, it was passed down from generation to generation until today. Although people's choice of clothes colors is no longer so limited, there are still many girls and boys wearing fancy clothes. However, this kind of attention has not disappeared. Many times, many people in many places still follow this fastidious style.