A vibrant and futuristic recruitment poster for the "SeaArc" universe, 16:9 aspect ratio. The scene depicts a bustling, multi-layered floating city (SeaArc) in the upper half, with illuminated coral-like structures, sleek submarine docks, and various residents (humans, anthropomorphic AI robots, and gentle, bioluminescent aquatic beings) interacting. In the lower half, the deep sea is visible, with mysterious, glowing flora, schools of exotic fish, and hints of ancient submerged ruins. A beam of sunlight or artificial light pierces the water, connecting the city to the depths. In the foreground, a diverse group of "citizens" (a repair technician with tools, an AI researcher with a submersible miniature, a whimsical bard with a sea creature companion, an old-era human looking thoughtful) stands together, looking out towards the viewer with expressions of welcome and adventure. The overall mood is hopeful, adventurous, and harmonious, with a blend of futuristic technology and natural oceanic beauty. The color palette emphasizes deep blues, radiant aquamarines, bioluminescent greens, and warm golden light from the city. Detailed, photorealistic, cinematic lighting, 8k, ultra quality.