It's just my theory but she desperately wanted to look average and be nothing special for some strange reason so I believe that her natural appearance is what she has when she is with the Emperor
But that guy was asking about her as a baby, with "Are you sure, it's not purple?" & to monitor her ever since (=・ω・=)
Maybe the mother figured out a way to hide her hair and eye color when she ran away with her.
Could be that
So, is purple her actual hair color?