>>1677702The official artwork is more like concept art. Just look at this Project Diva model, it's the official one so could I not say the same?
The great thing about Teto is that her entire existence has been built up by the fans of her character and the Vocaloid community. To keep that spirit I like to think that the true official colour (even though it is constantly changing) is the average colour of all Teto drawings ever done.