How two-toned are we talking about? Almost any character with 粉, 粉色 hair seems to have some lighter 粉, 粉色 and some darker 粉, 粉色 in them, depending on the light. 更多 of a contrast than Chokaku here from Koihime Musou? Should the lighter and darker shades actually be different colors, not related to how much light is shining on them?
