yasuzero, shinosawa_hiro, year_2024, 1girl, bikini, flat_chest, full_body, grey_hair, hat, innertube, jacket, long_hair, looking_at_viewer, navel, orange_eyes, sandals, smile, solo, straw_hat, swim_ring, swimsuit, unzipped, absurdres, highres, gakuen_idolmaster, idolmaster