A stylish young woman taking a mirror selfie in a modern luxury gym, sitting cross-legged on a wooden workout bench. She has long, straight dark-brown hair, a calm natural expression, and holds a black smartphone in front of her face. She wears a sleek all-black sleeveless athletic outfit with loose black pants and light-colored chunky sneakers, with a simple wristwatch. Spacious upscale gym interior with large mirrors, fitness machines, warm beige lighting, polished wooden flooring, clean minimalist atmosphere, soft ambient lighting, realistic photography, natural skin texture, shallow depth of field, subtle background blur, full-body composition, vertical 9:16, high detail.