hate to say it, but her hair is more of a blue isn't it?

For the older anime series Blue/Black/Dark Purple were pretty much interchangeable.

That said, I always thought she was more of a black haired girl, typical japanese girl you know?

At least, when it comes to looks.

CLAMP is pretty consistent with Japanese characters having Japanese hair color. (minus Rayearth their early work)

so yeah, it was black, using this dark blue tint