Koyama :))

the mc is in debt and he loves with his stepbrother who is also inlove with him, and he meets the ml who was blonde behind a car bcos mc was puking and he also accidentally spilt coffee on rhe ml’s shirt and their interactions were multiplying, I think the ml was a famous author too? and the stepbrother had a role-playing job

sooo it’s an office setting and they are enemies since high school, they make a bet on who ever falls inlove first loses, but the top was already inlove with the bottom from the start