SF：環状都市と青い惑星

Use case: stylized-concept. Create one standalone finished image for a premium prompt-gallery card. Portrait 3:4 composition, full bleed, no border. High-end cinematic photorealistic detail with a strong, instantly legible main subject sized large enough to read in a narrow thumbnail. Keep the essential subject in the central 80% so a portrait crop remains safe. No text, lettering, numbers, logos, watermarks, user interface, collage, panels, or recognizable franchise designs. Primary request: An original colossal orbital city, a gleaming inhabited ring with elegant radial towers, suspended above the curved horizon of a blue ocean planet. The city ring fills the middle of the portrait frame at a dramatic three-quarter angle, with the luminous planet covering the bottom third. A tiny sleek shuttle crossing the foreground establishes scale. Crisp engineering, glass habitation bands, believable metal joints and minute warm window lights. Deep cobalt space, restrained violet nebula haze, sunrise rim light catching the white-gold structure. Awe-inspiring, peaceful future. Cinematic 35mm view, dimensional depth, controlled highlight bloom, no excessive clutter.