>>11060661The Japanese school girl sailor uniform is on purpose where it actually sticks out among the cast of characters since most of them are either wearing very modern sci-fi urban wear or some variant of an ornate Chinese attire. So yeah, while it looks generic on the onset, she sticks out like a sore thumb within the setting. Also fits her character since she just wants to live a normal life despite being a wanted criminal/murderer on the run.
Also as this anon said
>>11060785, she originally wore an Eva-style pilot suit.