The default costume of Phase Connect's Jelly Hoshiumi, as seen in post #6346914.
It is a blue dress with short, white, puffy detached sleeves and matching gloves, a white collar with a blue bow, a yellow bow on the stomach, star ornaments on the skirt and in her hair, fake star antennae star on a yellow hairband, white thighhighs with garter straps and blue shoes.
This tag implicates jelly_hoshiumi (learn more).