Costume Analysis:

Raydance Says: The twins' Type C costumes are short yukatas, with what looks like black slippers. :)

Mayu wears a pink yukata with a squared pattern on it, with a purple obi. Mio wears a green yukata with a floral pattern, together with a hot pink obi. Both bows, according to Beyond the Camera's Lens are Butterfly Bows.

We've had a hard time finding something similar to the cloth patterns, but we think that these are pretty good substitutes. :)