Explorable Cinematic 3D Landscape World

You are an expert Three.js developer and 3D world designer specializing in atmospheric, exploration-focused browser experiences. Your strength is creating visually stunning, performance-optimized environments that prioritize composition, mood, and architectural wonder over gameplay mechanics.

Create a cinematic, freely explorable 3D browser world centered on {{world-theme}}. The experience should evoke pure visual discovery—no combat, no objectives, just breathtaking exploration.

## World Design Requirements

### Architecture & Structures
- Design monumental, original buildings that feel strange and ambitious—massive scale, impossible geometries, unforgettable silhouettes
- Include surreal ruins, colossal monuments, and ultra-detailed architectural elements that reward close inspection
- Make every structure feel purposeful in composition but mysterious in origin
- Vary architectural styles: organic flowing forms, brutal angular megastructures, delicate lattice towers, weathered ancient fragments

### Landscape & Environment
- Integrate dramatic natural features: towering cliffs, deep valleys, dense forests, reflective water bodies
- Create strong visual rhythms—alternate between open vistas and intimate enclosed spaces
- Use elevation changes to reveal new views and create memorable "hero shots"
- Design the terrain to guide exploration naturally through visual interest

### Atmosphere & Polish
- Implement dynamic lighting: volumetric fog, god rays, dramatic shadows, time-of-day or weather if performance allows
- Add environmental detail: particle systems (dust, mist, floating debris), ambient audio cues, wind-affected vegetation
- Optimize LoD (level of detail) aggressively—use impostors and billboards for distant elements
- Ensure smooth 60fps camera movement with WASD + mouse look controls

## Technical Implementation

**Stack**: Three.js (latest), vanilla JavaScript or lightweight framework

**Performance targets**:
- Initial load < 5s, lazy-load distant chunks
- Draw calls < 200 per frame; use instanced meshes for repeated elements
- Texture atlases for terrain; compressed formats (Basis, KTX2) preferred

**Camera system**: Smooth free-fly or third-person with collision detection, adjustable speed (shift-sprint, ctrl-slow), optional cinematic camera paths or auto-framing for key vistas

**Architecture generation**: Procedural + hand-placed hero structures. Use modular pieces that combine into unique forms. Bias toward verticality and layering.

**Code structure**: ModularScene Manager, Asset Loader, Camera Controller, Lighting System, Post-Processing (bloom, SSAO, color grading). Comment architectural design patterns and optimization choices.

Output the complete, production-ready codebase with clear setup instructions. Prioritize visual impact and atmosphere above all—this should feel like exploring a concept art painting come to life.