Bit of a long shot, but I'm looking for a one shot that I read a really long time ago. I think it was part of a collection of one shots, maybe the second or third story, and it was about a girl getting locked in on the school rooftop together with her ex-boyfriend. I think at one point it gets cold and he offers her his jacket, and eventually they make up and get back together. It was a pretty old art style from what I remember as well. I doubt anyone has read it but any help would be appreciated!

This sounds like the last story in Ninohime no Monogatari.

that's the one thank you! it was much worse than I remember it being lmao but I'm glad I finally got to read it again!