A realistic photography showing a documentary moment in the gym. In the center of the picture is a young woman with a well-proportioned figure and clear muscle lines. Her upper body is wearing a dark purple tight-fitting navel-baring camisole. The fabric of the clothing is close to the body and shows the chest lines and abdominal muscles. The lower body is paired with pure black ultra-low-waisted tights, showing off her round buttocks. Wearing retro white canvas shoes. She stood sideways, holding a smartphone with dual cameras in her right hand and taking a selfie in the mirror, her eyes focused. The background is a real gym environment. The floor is paved with dark gray non-slip rubber mats with a frosted grain texture. There are silver-gray metal dumbbell racks, tensioners and various professional weight equipment scattered around. There are blurred figures of fitness crowds in the distant view, which enhances the liveliness of the space. Several rows of parallel cold fluorescent tubes are distributed on the ceiling. The light is spread evenly, outlining a soft edge light on the back and shoulders of the characters, and forming soft shadows on the ground. The composition is shot from a distance, the characters are tall and straight and have great visual tension. The picture has real sensitivity noise and a life-like shooting perspective. 35mm lens, f/4.0 aperture