I found this yesterday. Logically explained, light on maths.
This blog post is an introduction to the CIE 1931 color system, an international standard model of human color vision that is used all around you. Do you see any color prints around you? Are you reading this on a color display? All of that is made possible by CIE 1931.
https://medium.com/hipster-color-science/a-beginners-guide-to-colorimetry-401f1830b65a