To translate and understand it better:
A carousel post. Slide 1: The manga cover. Slide 2: A scenic panel of the apartment complex. Slide 3: A dialogue-heavy emotional scene. joshiochi 2kai kara onnanoko ga futtekita top
No theory is confirmed. The author has stated in an interview: "Don’t think about it. Just laugh." To translate and understand it better: [Image Idea]:
Miki is the childhood friend archetype, but with a twist. She has been watching Kazuya through his ceiling (her floor) for years. When Lilia falls into his life, Miki decides to aggressively insert herself into the situation. No theory is confirmed