1girl, bare_shoulders, bikini, black_bikini, blunt_bangs, brown_eyes, from_behind, halterneck, idolmaster, idolmaster_cinderella_girls, kamiya_nao, light_brown_hair, looking_at_viewer, looking_back, nikukai, side-tie_bikini_bottom, simple_background, sitting, solo, string_bikini, swimsuit, thick_eyebrows, wariza, white_background