Create a 9:16 vertical screenshot-style image of a brand-neutral Chinese livestream app interface. The scene shows an authorized or fictional streamer named [Streamer Name] broadcasting live at night, smiling happily and facing the camera. The streamer holds a large handwritten sign with the exact message: [Sign Message]. Design the screen like a mobile livestream: dark translucent top status bar, streamer avatar and name area, follow button, viewer count, ranking badges, small circular viewer thumbnails, floating gift animations, chat comments along the lower left, and bottom input/action buttons. Keep the interface lively and realistic but do not copy any real platform logo, mascot, icon set, or official app branding. The background can be an outdoor urban night scene with streetlights and soft bokeh, but avoid recognizable store logos or private information. The sign should be large and readable, with friendly handwritten Chinese-style lettering if the message is Chinese. Preserve a casual social-streaming mood: cheerful expression, relaxed posture, handheld sign centered in the lower half, vertical phone screenshot framing, soft night lighting, and clear UI hierarchy. Avoid celebrity likeness unless authorized, real platform names, copied logos, private account data, offensive chat content, unreadable sign text, malformed hands, distorted face, extra watermarks, and low-resolution artifacts.