城市日转夜锁定延时

Subject: an entire dense city skyline. Action: locked-off wide shot from a high vantage; morning light sweeps across the rooftops, shadows rotate, clouds roll through in fast motion, afternoon haze settles, then city lights ignite one cluster at a time as dusk falls; the final ten seconds slow to real time with a helicopter tracking slowly across frame. Scene: a generic large city downtown. Light: full daylight cycle baked into the timelapse, ending in cool night with motivated practical city light. Camera: a single locked tripod position throughout, no cuts. Style: nature-doc timelapse cinematic. Audio: subtle ambient city drone, single helicopter blade hum at the end. Constraints: no watermark, no text overlays, no scene cuts.