server {
    listen 80;
    server_name _;
    root /usr/share/nginx/html;
    index index.html;

    # Gzip for the text assets.
    gzip on;
    gzip_types text/html text/css application/javascript application/json image/svg+xml;
    gzip_min_length 512;

    # Lightweight health endpoint for Coolify / Docker healthcheck.
    location = /healthz {
        access_log off;
        add_header Content-Type text/plain;
        return 200 "ok\n";
    }

    # Vendor libs + fonts can be cached hard.
    location /vendor/ {
        expires 30d;
        add_header Cache-Control "public, immutable";
    }

    # Service worker and manifest must always revalidate.
    location = /sw.js {
        add_header Cache-Control "no-cache";
    }
    location = /manifest.webmanifest {
        default_type application/manifest+json;
        add_header Cache-Control "no-cache";
    }

    # Never cache the app shell, so updates land immediately.
    location = /index.html {
        add_header Cache-Control "no-cache";
    }

    location / {
        try_files $uri $uri.html $uri/ /index.html;
    }

    # Hardening headers.
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "DENY" always;
    add_header Referrer-Policy "no-referrer" always;
    add_header Strict-Transport-Security "max-age=31536000" always;
    add_header Permissions-Policy "geolocation=(), camera=(), microphone=(), payment=(), usb=(), interest-cohort=()" always;

    # Content Security Policy.
    # connect-src 'none' ist hier das eigentliche Versprechen: der Browser selbst
    # unterbindet jede fetch/XHR/WebSocket-Verbindung. "Nothing is uploaded" ist damit
    # nicht nur behauptet, sondern erzwungen. img-src erlaubt https, damit Bilder aus
    # eingefuegtem Markdown in der Vorschau sichtbar bleiben.
    add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob: https:; font-src 'self'; connect-src 'none'; object-src 'none'; frame-src 'none'; frame-ancestors 'none'; base-uri 'none'; form-action 'none'; manifest-src 'self'; worker-src 'self'" always;
}