A vast underwater scene featuring a fantastical steampunk submarine, reminiscent of the Nautilus from Jules Verne's tales, drifting through a luminescent coral reef. Its brass and copper exterior gleams in the filtered sunlight, with rotating gears and intricately etched patterns covering its hull. The submarine's large glass portholes glow with a warm light, revealing a glimpse of shadowy figures moving inside. Sea creatures, curious about this mechanical marvel, swim alongside, their vibrant colors contrasting with the submarine's metallic sheen. Shafts of light penetrate the ocean's surface above, casting a mystical aura over the entire scene.