钢琴家蝴蝶光（中景情感） prompt

Subject: a pianist in his 30s wearing a simple, elegant black suit. Action: his fingers move across the keys with precision and emotion; he leans slightly into the keyboard during a crescendo, then settles back. Scene: a concert hall stage at evening. Light: classic butterfly lighting from above-front (slightly higher than 45 degrees), a single warm spotlight, soft fall-off behind. Camera: medium shot, locked-off, no movement. Style: cinematic concert film, shallow depth of field. Audio: solo piano, faint audience presence in the background. Constraints: maintain face stable, no watermark, no text, no extra hands.