Make a browser animation of a zebra running across the African savanna, side view, like a nature documentary shot. Get the gallop right: legs, body bounce, head, mane and tail all moving like a real zebra. Golden-hour light, grass that sways, acacia trees and distant hills with parallax, dust kicked up by the hooves. It should loop smoothly and look great the moment it loads. Single HTML page, no external images or video.