Our class colors are light blue and dark blue. What does that mean? What are they for?

Well, apparently, the concept started early in the 20th century at universities such as Harvard. Each class was assigned a color at a ceremony freshman year. This color was used to distinguish individual classes at sporting events and such. The purpose was to build class spirit and class loyalty. The concept had mostly disappeared by the 1960s. Harvard reinstated the class color system in 2015 to help build class spirit and cohesiveness.