server {
    listen 80;
    server_name localhost;

    root /usr/share/nginx/html;
    index index.html index.htm;

    # Gzip compression for high performance
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied any;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript image/svg+xml;

    # SPA routing: fallback to index.html for client-side routing
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Cache static assets with long TTL
    location /assets/ {
        expires 1y;
        add_header Cache-Control "public, no-transform, immutable";
    }

    # Security headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;

    # Health check endpoint
    location /healthz {
        access_log off;
        return 200 "healthy\n";
    }
}