Hecatia’s changing hair colour

I don’t know if you have noticed, but everytime you clear a spellcard, Hecatia’s hair colour resets back to red. 

That means she changes her hair colour only from red to blue or red to yellow. Never from yellow to blue or blue to yellow. 

But there’s another interesting fact: sometimes when she turns blonde, her sprite displays for a short time period a blue-greenish shade, even though the hair colour changes from red to yellow.

It’s not something wow, but it’s nice to know.