Hareta Hi no Dress Code 

If only I could wear my favorite clothes however I want— Natsuki Yonei, a first-year high school girl, thought about wearing slacks to school, but she ended up going with the "safe" option of a skirt instead. But there is one girl, Miwa Omi, who is wearing pants, even though all the other girls are wearing skirts. Intrigued, Natsuki tries to befriend her, and she learns the reason why Miwa doesn't wear skirts... A first-love in uniform, a sparkling yet slightly bittersweet chapter of high school life.