National Style City Promotion Poster

Generate a vertical city promotional poster for city_name. Do not use fixed templates; first extract the city's unique cultural background, geographical environment, industrial development, and urban philosophy, then design the composition. The image must be instantly recognizable as city_name: select the most identifiable historical symbols, natural landmarks, modern features, and future visions. Composition is flexible. Requirements: Historical culture (traditional architecture, folklore), modern development (skyline, technology, ecology), and urban spirit (innovation, internationalization). Poster quality: 9:16 vertical, high-end 'Guochao' style, realistic digital painting blended with ink/light effects, cinematic lighting, high detail, commercial layout. Text: The city name "city_name" as a calligraphic title, plus a slogan; avoid messy small text. No generic collages, incorrect landmarks, or cheap advertising feel.