what is the meaning of the colour of the mothers clothes?

We first see the Mother dancing in the field and she is wearing shades of blue, eg. a blue dress and purple coat. Thereafter we see her wearing red, whereas everyone else wears shades of blue. When she is getting close to the truth she is wearing a purple coat and after she finds out the truth she goes to dance in the field again. She is wearing a blue dress underneath her purple coat so we can assume this is the same dancing scene as the beginning. After that she returns to wearing red again.

What do you think is the meaning of the colour of her clothes? Red to blue to red again.