window.addEventListener('DOMContentLoaded', () => {
    const el = document.createElement('div');
    el.textContent = '✅ Header script working';
    el.style.cssText = 'position:fixed;top:0;left:0;background:lime;color:black;padding:8px;z-index:99999;font-family:monospace';
    document.body.appendChild(el);
  });