>>717854439 (OP)
"Blue" in Anime/Jap terms just means youth. The color is supposed to represent the feeling that you're in the peak of your life and a world of possibilities are in front of you. That's why a shit ton of anime have blue in the title
So we extrapolate that then to the word Archive, as in a record or historical documentation
And you get something like Records of Youth, which is fitting for a game about high school girls having fun together.