Mermaid, fantasy, underwater city, majestic castle, grand staircase, shimmering scales, flowing golden hair, seashell bra, pearl necklace, fish-tail skirt, delicate fins, sparkling eyes, soft focus, warm lighting, vibrant coral, seaweed, schools of small fish, sunken shipwrecks, treasure chests, ancient ruins, mysterious artifacts, misty atmosphere, dreamy composition, cinematic color grading.