The default costume of hololive English's Tsukumo Sana, as seen in post #4723656 and post #4726987.
It consists of a white skin tight halter shirt, white elbow gloves, a backless underbust blue leotard worn under a pleated see-through white miniskirt and a blue skirt overskirt with a starry sky print held with a blue back bow and an anklet. She also goes barefoot and paints her toenails blue.
This tag implicates tsukumo_sana (learn more).