Roommate complaining about cat smell

I live in a college dorm with a small room fit for 2 people and around 2 months ago, I adopted a male kitten that I absolutely adore. My roommate usually never complains since she likes the kitten too but these days, she had been complaining that every time she enters our shared room, it always has a cat smell. I never noticed at all so I never did anything before. I cleaned the litter box often, and made sure that the kitten isn't dirty. I did everything I could to keep the room clean but I don't really know how to get rid of that cat smell that my roommate kept complaining about.

Cat parents, Please I need advice...