Hi :) ! Some parts depends on other colors in the game. For exemple, in the "The sun was setting fire to the sky" chapter, the left branch is the color of the couch you picked in the green sky chapter (when the girls pick the colors they want for their future home).
The warm afternoon depends on a color in the first sky, with the spring blue sky. I don't want to say too much, but if you need more precisions feel free to ask! :)
(and thanks for playing the game! It warms my heart to see people really dig into the story that way ;;/)