# Game Systems

Core mechanics that govern how the game economy and logistics work.

## Expansion
- [Settlement](./settlement.md) - Settling new islands and cities

## Trade & Logistics
- [Trading](./trading.md) - Complete trading system overview (passive, active, contracts)
- [Trade Routes](./trade-routes.md) - Automated ship loops between islands
- [Diplomatic Trade](./diplomatic-trade.md) - Passive buy/sell with AI via treaties

## Progression
- [Accolades](./accolades.md) - Hall of Fame metaprogression and achievements
- [Skill Tree](./skill-tree.md) - Research system for unlocking buildings, bonuses, and abilities

## Economy
- [Maintenance Model](./maintenance.md) - Building upkeep and workforce costs
- [Area Effects](./area-effects.md) - Proximity bonuses and penalties
- [Statistics Screen](./statistics-screen.md) - Production vs consumption diagnostics
- [Specialists](./specialists.md) - Specialist items system, categories, and acquisition

## Resources
- [Fertility](./fertility.md) - Island resource availability and regional differences

## City Management
- [Citizen Needs](./citizen-needs.md) - Goods and services required by each population tier
- [City Status](./city-status.md) - Population thresholds, bonuses, and penalties
- [Health, Happiness & Fire Safety](./health-happiness-fire.md) - Incident prevention and City Watch

## Infrastructure
- [Shipyard](./shipyard.md) - Ship construction system
- [Warehouse Cloud](./warehouse-cloud.md) - Shared island storage

## Key Concepts

### Maintenance
Nearly every building has ongoing gold + workforce maintenance:
- Fishing Hut: -6 gold/min, 4 Tier I workers
- Bakery: -14 gold/min, 3 Tier II workers
- Deleting buildings stops upkeep and frees workforce

### Area Effects
Buildings can give positive/negative proximity modifiers:
- Shown by green/red arrows on placement
- Spinner gives income boost near buildings
- Polluters (e.g., Charcoal Burner) decrease happiness/health
