document.addEventListener('DOMContentLoaded', function() {
    const navToggle = document.getElementById('navToggle');
    const navMenu = document.getElementById('navMenu');
    const body = document.body;
    const goTopBtn = document.getElementById('goTop');
    
    // 汉堡菜单切换
    if (navToggle && navMenu) {
        navToggle.addEventListener('click', function(e) {
            e.stopPropagation();
            this.classList.toggle('active');
            navMenu.classList.toggle('active');
            body.classList.toggle('nav-open');
        });
        
        // 点击菜单项自动关闭
        navMenu.querySelectorAll('a').forEach(link => {
            link.addEventListener('click', () => {
                if (window.innerWidth <= 768) {
                    navToggle.classList.remove('active');
                    navMenu.classList.remove('active');
                    body.classList.remove('nav-open');
                }
            });
        });
        
        // 点击外部区域关闭菜单
        document.addEventListener('click', function(e) {
            if (navMenu.classList.contains('active') && 
                !navToggle.contains(e.target) && 
                !navMenu.contains(e.target)) {
                navToggle.classList.remove('active');
                navMenu.classList.remove('active');
                body.classList.remove('nav-open');
            }
        });
    }
    
    // 返回顶部按钮
    if (goTopBtn) {
        window.addEventListener('scroll', () => {
            goTopBtn.style.display = (window.scrollY > 300) ? 'block' : 'none';
        });
        
        goTopBtn.addEventListener('click', () => {
            window.scrollTo({ 
                top: 0, 
                behavior: 'smooth' 
            });
        });
    }
    
    // 导航栏滚动阴影
    const header = document.querySelector('.main-header');
    if (header) {
        window.addEventListener('scroll', () => {
            header.classList.toggle('scrolled', window.scrollY > 10);
        });
    }
    
    // 表单验证增强（移动端友好）
    const phoneInputs = document.querySelectorAll('input[type="tel"]');
    phoneInputs.forEach(input => {
        input.addEventListener('input', function() {
            this.value = this.value.replace(/[^\d]/g, '');
            if (this.value.length > 11) {
                this.value = this.value.slice(0, 11);
            }
        });
    });
    
    // 图片懒加载（原生支持）
    if ('loading' in HTMLImageElement.prototype) {
        const images = document.querySelectorAll('img[loading="lazy"]');
        images.forEach(img => {
            img.setAttribute('src', img.dataset.src || img.getAttribute('src'));
        });
    } else {
        // 降级处理：立即加载
        document.querySelectorAll('img[loading="lazy"]').forEach(img => {
            img.removeAttribute('loading');
        });
    }
    
    // 防止iOS Safari橡皮筋效果（可选）
    if (/iPhone|iPad|iPod/.test(navigator.userAgent)) {
        let startY = 0;
        document.body.addEventListener('touchstart', function(e) {
            startY = e.touches[0].clientY;
        });
        document.body.addEventListener('touchmove', function(e) {
            const scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
            if ((scrollTop === 0 && e.touches[0].clientY > startY) || 
                (scrollTop === document.body.scrollHeight - window.innerHeight && e.touches[0].clientY < startY)) {
                e.preventDefault();
            }
        });
    }
});