// 汉堡菜单切换
document.addEventListener('DOMContentLoaded', function() {
  const menuToggle = document.querySelector('.menu-toggle');
  const siteNav = document.querySelector('.site-nav');
  
  if (menuToggle && siteNav) {
    menuToggle.addEventListener('click', function() {
      this.classList.toggle('active');
      siteNav.classList.toggle('active');
      const isOpen = siteNav.classList.contains('active');
      this.setAttribute('aria-expanded', isOpen);
    });
  }
});