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

    # Security headers
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;
    add_header Permissions-Policy "camera=(), microphone=(), geolocation=()" always;

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

    # Cache static assets (hashed filenames — safe to cache forever)
    location /assets/ {
        expires 1y;
        add_header Cache-Control "public, immutable";
    }

    # Don't cache index.html (SPA entry point must always be fresh)
    location = /index.html {
        add_header Cache-Control "no-cache, no-store, must-revalidate";
        add_header Pragma "no-cache";
        add_header Expires "0";
    }

    # Gzip
    gzip on;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml text/javascript image/svg+xml;
    gzip_min_length 256;
}
