Hilarious, if you finish the Sugar Rush event, you get a 3d music video which shows Kazusa isn't flat in her t-shirt as some fans thought.
That was the problem. The official art her chest is like a chopping board but her 3D sprite says otherwise. It feels like the artist and the one who makes the 3D sprites didn't collaborate enough
None of the official art supports Kazusa having anything more than the very lower end of what we would call medium breasts. In fact, the clearest official art (the one being complained about in these comments) appears almost flat. No excuse for the over-inflation in fanart. Even the classic "sweater/hoodie/jacket hides it" excuse. To paraphrase the above: If you just look at the official art, you get images which show Kazusa doesn't have a huge chest in her jacket as some fans thought.
