1girl, b1ack_illust, bikini, blue_hair, breasts, cleavage, collarbone, dark_blue_hair, day, frilled_bikini, frills, hand_in_own_hair, idolmaster, idolmaster_million_live!, looking_at_viewer, medium_breasts, navel, official_alternate_hairstyle, outdoors, ponytail, pool, pool_ladder, poolside, sidelocks, smile, solo, swimsuit, thigh_gap, toyokawa_fuka, water_drop