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

    # Gzip compression
    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_types text/plain text/css text/xml text/javascript application/javascript application/json;

    # Security headers (enhanced for admin panel)
    add_header X-Frame-Options "DENY" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header Referrer-Policy "strict-origin-when-cross-origin" always;

    # Cache static assets
    location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
        expires 1h;
        add_header Cache-Control "private, must-revalidate";
    }

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

    # Health check endpoint
    location /health {
        access_log off;
        return 200 "OK";
        add_header Content-Type text/plain;
    }

    # Security - deny access to hidden files
    location ~ /\. {
        deny all;
    }
}