The uniform worn by members of the Chaldea Security Organization in Fate/Grand Order.
There are many variants of the uniform, depending on the rank and position the member is. Male Ritsuka and Female Ritsuka wear a white shirt with black buckles on the chest, with the male uniform having black pants and the female uniform having a black skirt, black pantyhose, and white knee boots. Romani Archaman wears a doctor's uniform beneath a white coat. Other staff members like Jeancle Abel Meuniere and Sylvia wear a black shirt with the secondary color being different depending on the gender - orange for women, and aqua for men - and either white pants or a white skirt.
Dark Young has the same coloration as the protagonists' Chaldea uniforms.