Whispering Sakura River

Generate a 12-second 4K, 24fps cinematic video of pale-pink sakura petals drifting along a clear mountain river at golden hour. Camera: slow gimbal dolly from low angle across water surface, shallow depth of field, soft lens flare. Emphasize micro-ripples, bokeh, and petal textures. Natural sound design of water and birds implied. No text, no watermark.