Implement a Content Security Policy (CSP) Header

server {
    listen 80;
    server_name example.com www.example.com;

    # Redirect HTTP to HTTPS
    return 301 https://$host$request_uri;
}

server {
    listen 443 ssl;
    server_name example.com www.example.com;

    # SSL certificate configuration
    # ...

    # Content Security Policy (CSP) header
    # This CSP allows scripts and styles only from the same origin,
    # images from any origin, fonts from Google Fonts,
    # and disallows object/embed tags.
    add_header Content-Security-Policy "default-src 'self';
          script-src 'self' https://trusted.cdn.com;
          style-src 'self' 'unsafe-inline' https://fonts.googleapis.com;
          img-src 'self' data: https:;
          font-src 'self' https://fonts.gstatic.com;
          object-src 'none';
          base-uri 'self';
          form-action 'self';
          frame-ancestors 'self';";

    # Other security headers (optional but recommended)
    add_header X-Frame-Options "SAMEORIGIN";
    add_header X-Content-Type-Options "nosniff";
    add_header X-XSS-Protection "1; mode=block";
    add_header Referrer-Policy "no-referrer-when-downgrade";

    root /var/www/html;
    index index.html index.htm;

    location / {
        try_files $uri $uri/ =404;
    }
}