Every Atcoder contest has a color related to it, like for AGC, it is red, and for ARC, it is yellow. For contests between ABC042 to ABC125, it was green, then it turned blue when the number of tasks increased to 6 from 4. Now, the number of problems is 8, color is not changed. Is it related to something else? Please explain it to me.
Maybe it's the upper bound of rated participation.