(() => {
  document.querySelectorAll('.nav-item.has-children').forEach(group => {
    const btn = group.querySelector('.nav-item-btn');
    const caret = btn.querySelector('.caret');
    const children = group.querySelector('.nav-children');
    btn.addEventListener('click', () => {
      children.classList.toggle('open');
      caret.classList.toggle('rotate');
    });
  });
})();