Gakuran’s hair is fire red in the source character info I found, not white or black.

Quick note

If you meant a specific Roblox avatar or skin based on Gakuran, the exact hair color can vary by the outfit creator, but the character reference itself lists fire red.

Related Roblox context

Roblox hair items come in many colors, including black, blue, red, golden, rainbow, and teal, so creators can match Gakuran with different looks depending on the version they’re making.

TL;DR: Gakuran’s canon hair color is fire red.