GRAVITY STEP：极限鱼眼球鞋广告

Create a premium vertical streetwear advertising poster for a fictional urban footwear brand called GRAVITY STEP. Use an extreme worm's-eye fisheye perspective from ground level in the middle of a city street, looking dramatically upward. A stylized yet premium urban mascot character towers above the viewer. One massive sneaker sole thrusts directly toward the camera from the lower-right foreground, dominating the frame, while one open hand reaches toward the lens from the lower-left foreground in dynamic perspective. The body sits in the middle distance, framed by tall curved city buildings that rise around the edges into a bright sky opening above.