flowchart TB
    classDef frontend fill:#6366f1,stroke:#4338ca,color:#fff
    classDef backend fill:#0ea5e9,stroke:#0284c7,color:#fff
    classDef external fill:#f59e0b,stroke:#d97706,color:#fff

    subgraph FE["Frontend"]
        SearchBar["SearchBar"]
        Filters["Filters"]
        ResultList["ResultList"]
        MapView["MapView — Leaflet.js"]
    end

    subgraph BE["Backend"]
        route["route.ts — Request Handler"]
        parser["parser.ts — NLP Engine"]
        geo["geo.ts — Geocoding"]
        overpass["overpass.ts — OSM Query Builder"]
        cache["cache.ts — Cache Layer"]
    end

    subgraph EX["External APIs"]
        Nominatim["Nominatim — Geocoding API"]
        OverpassAPI["Overpass API — OSM Data"]
    end

    SearchBar & Filters & ResultList & MapView -->|"POST /api/search"| route

    route -->|"parse query"| parser
    route -->|"resolve location"| geo
    route -->|"fetch POIs"| overpass
    route <-->|"read / write"| cache

    geo -->|"geocode"| Nominatim
    overpass -->|"QL query"| OverpassAPI

    class SearchBar,Filters,ResultList,MapView frontend
    class route,parser,geo,overpass,cache backend
    class Nominatim,OverpassAPI external