server {
    listen 80;
    server_name quantumtaskai.com www.quantumtaskai.com;
    root /usr/share/nginx/html;
    index index.html;
    charset utf-8;

    # ── Security headers ─────────────────────────────────────────
    add_header X-Frame-Options "SAMEORIGIN" 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;
    add_header Permissions-Policy "camera=(), microphone=(), geolocation=()" always;

    # ── Gzip compression ─────────────────────────────────────────
    gzip on;
    gzip_types text/plain text/css text/javascript application/javascript
               application/json image/svg+xml;
    gzip_min_length 1024;

    # ── Caching: HTML (1 hour) ───────────────────────────────────
    location ~* \.html$ {
        add_header Cache-Control "public, max-age=3600, must-revalidate";
        add_header X-Frame-Options "SAMEORIGIN" always;
        add_header X-Content-Type-Options "nosniff" always;
        try_files $uri $uri/ =404;
    }

    # ── Caching: Static assets (1 year) ─────────────────────────
    location ~* \.(ico|png|jpg|jpeg|webp|gif|svg|woff|woff2|ttf|js|css)$ {
        add_header Cache-Control "public, max-age=31536000, immutable";
        access_log off;
        try_files $uri =404;
    }

    # ── Caching: sitemap and robots (1 day) ─────────────────────
    location ~* \.(xml|txt)$ {
        add_header Cache-Control "public, max-age=86400";
        try_files $uri =404;
    }

    # ── www → non-www redirect ───────────────────────────────────
    if ($host = "www.quantumtaskai.com") {
        return 301 https://quantumtaskai.com$request_uri;
    }

    # ── Main routing ─────────────────────────────────────────────
    location / {
        try_files $uri $uri/ $uri.html =404;
    }

    # ── 404 page ─────────────────────────────────────────────────
    error_page 404 /404.html;
    location = /404.html {
        internal;
    }
}