A medium shot from behind and a low-angle view shows a (solo:1.0) man in his 40s immersed up to mid-back in a large, pond-like Japanese open-air bath at night. The man has a (grown-up face:1.0) and a (toned body:1.0) with (muscular body:1.0) features, his (beautiful back muscles:1.0) prominently defined and glistening with sweat. He has (black hair:1.2) that is short with (parted bangs:1.0) and ends that are flipped out, and he is (facing up:1.0) toward the sky. He is surrounded by the serene outdoors of an onsen, with vivid red maple and yellow ginkgo autumn leaves framing the water's edge. A bright moon hangs in the night sky, casting ethereal moonlight through swirling steam over the water. The visual style is a (realistic:0.8) watercolor painting with soft tones, soft brushstrokes, and natural lighting, creating a beautiful and exquisite anime illustration with a tranquil, nocturnal atmosphere.
