1girl, arms_behind_head, bikini, braid, breasts, cleavage, cleavage_cutout, clothing_cutout, colorado_(kancolle), dated, greyscale, h2_(h20000000), headgear, horizon, kantai_collection, large_breasts, monochrome, navel, ocean, sideboob, signature, solo, sun, swimsuit, thighhighs, tilted_headwear