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

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

    # Security headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;

    # Cache static assets
    location ~* \.(css|js|png|jpg|jpeg|gif|svg|ico|woff2?)$ {
        expires 30d;
        add_header Cache-Control "public, immutable";
    }

    # Service worker - no cache
    location = /sw.js {
        expires -1;
        add_header Cache-Control "no-store, no-cache, must-revalidate";
    }

    # SPA fallback
    location / {
        try_files $uri $uri/ /index.html;
    }
}