I was going to ask what their fight was about, but I realize that arguing, bickering, picking at each other was a foundation of their friendship from day one. That doesn't stop my curiosity, but rather increases my being impressed: You had the dynamic of these two figured out from the get-go. It totally makes sense, given canon-material for them. If they didn't kill each other, then they'd end up as friends of a sort, but never in a completely relaxed friendship.
Yay for more colors, and the deliberately cute / cheesy heart and sunshine at the end!