乐手后台人像

生成一张 4:5 竖版乐手后台人像。中国年轻男性吉他手坐在演出后台的旧沙发上，穿黑色无字夹克和深色牛仔裤，低头给一把无品牌木吉他调弦，身旁是打开的无字琴盒、卷好的线缆和一盏暖色台灯。背景为深色幕布、挂衣架和虚化舞台入口光，不出现观众或舞台表演。构图为半身到膝部环境肖像，人物偏左，吉他横向形成视觉线条。光线为后台暖灯和门缝冷蓝光，色调暖棕、黑、冷蓝。真实后台纪实摄影，50mm 镜头，人物比例和手部自然。画面内不要出现任何可读文字、logo、水印、品牌、演出海报、票据或琴头标识。

Create a 4:5 vertical backstage musician portrait. A young Chinese male guitarist sits on an old sofa backstage before a performance, wearing a plain black jacket and dark jeans. He looks down while tuning an unbranded wooden guitar; beside him are an open text-free guitar case, coiled cables, and a warm table lamp. The background has dark curtains, a clothing rack, and blurred light from the stage entrance, with no audience or live stage performance. Half-body to knee-level environmental portrait, subject slightly left, guitar forming a horizontal visual line. Lighting from warm backstage lamp and cool blue light through the doorway; palette of warm brown, black, and cool blue. Real backstage documentary photography, 50mm lens, natural proportions and hands. No readable text, logo, watermark, brand, show poster, ticket, or headstock mark anywhere.