document.addEventListener('DOMContentLoaded', function() {

const backToTopButton = document.getElementById('back-to-top');

const mobileNavToggle = document.getElementById('mobile-nav-toggle');

const mobileNavClose = document.getElementById('mobile-nav-close');

const mobileNavOverlay = document.getElementById('mobile-nav-overlay');

// 显示/隐藏返回顶部按钮

window.addEventListener('scroll', function() {

if (window.pageYOffset > 300) {

backToTopButton.style.display = 'block';

} else {

backToTopButton.style.display = 'none';

}

});

// 点击返回顶部

backToTopButton.addEventListener('click', function() {

window.scrollTo({

top: 0,

behavior: 'smooth'

});

});

// 移动端导航栏切换

mobileNavToggle.addEventListener('click', function() {

mobileNavOverlay.classList.add('show');

});

mobileNavClose.addEventListener('click', function() {

mobileNavOverlay.classList.remove('show');

});

// 点击导航链接关闭遮罩层

const mobileNavLinks = document.querySelectorAll('.mobile-nav-overlay .city-nav a');

mobileNavLinks.forEach(link => {

link.addEventListener('click', function() {

mobileNavOverlay.classList.remove('show');

});

});

});