A bustling, retro-futuristic city at twilight, with towering art deco skyscrapers interlaced with glowing, pneumatic tube transport systems. Flying vehicles resembling ornate dirigibles navigate the airways, casting long shadows. The sky is a deep indigo, illuminated by a colossal, stylized moon and nebulae of vibrant hues. Inspired by the illustrations of Moebius and the art of the 'Metropolis' film.