masterpiece, best quality, clean anime illustration, 1girl, solo, silver hair, medium ponytail, slightly messy hair, vivid blue eyes, detailed blue irises, tsurime, sharp eyes, thin delicate eyelashes, (flat chest:1.3), slender figure, cool sharp gaze, matte charcoal-gray high-neck sporty bikini top, secure coverage, clean white centerline piping, charcoal high-waisted bikini bottoms, barefoot, butterfly sitting, spread toes, full body, from below, looking at viewer