Koisuru Hotaru to Kurashiteru

Koisuru Hotaru to Kurashiteru summary:

He's a little difficult to understand, but he's kind.

Due to a renovation, high school student, Mayama Suzu, has to freeload at the home of one of her mom's friends.
However, the family's son is actually her classmate, Saeki Hotaru, who's a total downer.
Thus begins their sudden co-habitation due to special circumstances, all the while keeping it a secret at school.
She had always wanted to close the distance, but living together under one roof is the distance of love…