I remember a while back I read a manhwa and I really can't remember the name!!! It's similar to Chocolat. It's about a high schooler who wants to be a fashion designer. She lives in Korea and suddenly meets a band out of no where. She didn't even realize who they were until they took her out to dinner. She goes to they're school and one of them moves in with her and her father (who works with them). I remember the last part I read was when she passed out on the track from exhaustion caused by making they're concert costumes.

I believe you are looking for Ardour.