This design shows a strong, athletic horse striding across the scene, its rich brown coat set off by bright white markings that trail along its body like a shared secret between old friends. A long, dark mane and tail sweep back as if caught by a steady breeze, adding a sense of forward motion and freedom 🎉. The horse holds its head high with an alert gaze and slightly flared nostrils, giving it a confident, lively presence. Soft, diffused light falls across the coat, shaping gentle shadows over the muscles and making the contours look sculpted. Behind it, the sky fades from muted teal-gray near the top down to warm beige near the horizon, suggesting wide open land. Along the lower edge, a field of golden, dry grasses stretches forward with a few glowing, out-of-focus light specks that feel like little sparks of celebration 🎂. Near the top area, a short birthday greeting sits in small, light-colored lettering against the darker part of the sky.