Black School Rules (2019)

Sōra is a high school student who is basically invisible at school. He is friends with Chūya, who is an unpredictable character that often surprises those around him. Sōra and Chūya both have feelings for the same classmate, Kio Machida. The Machida girl refuses to come to class, because she doesn't want to dye her naturally brown hair black. Their school has unreasonable school rules, especially about uniforms, which include requiring all students to have black hair. Sōra and Chūya decide to stand up to change their school's black school rules so that Machida won’t have to repeat a year of school from missing too many classes.

Unfortunately the movie Black School Rules is not yet available on HBO Max.