/* 基础样式设置 */
        :root {
            --primary-color: #0066cc;
            --dark-color: #333;
            --light-color: #fff;
            --gray-color: #f5f5f5;
            --transition: all 0.3s ease;
        }

        /* 顶部信息栏 */
        .header_top {
            background-color: var(--light-color);
            padding: 10px 5%;
            display: flex;
            justify-content: space-between;
            align-items: center;
            box-shadow: 0 2px 5px rgba(0,0,0,0.05);
            transition: var(--transition);
        }

        .welcome-text {
            font-size: 14px;
            color: #666;
        }

        .contact-info {
            display: flex;
            align-items: center;
        }

        .contact-text {
            margin-right: 10px;
            font-size: 14px;
            color: #666;
        }

        .phone-number {
            font-weight: bold;
            font-size: 16px;
            color: var(--primary-color);
        }

        /* 主导航区域 */
        .header_main {
            background-color: var(--light-color);
            padding: 15px 5%;
            display: flex;
            justify-content: space-between;
            align-items: center;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
            position: sticky;
            top: 0;
            z-index: 1000;
            transition: var(--transition);
        }

        .logo-container {
            display: flex;
            align-items: center;
        }

        .logo {
            height: 50px;
            width: auto;
        }

        /* 桌面端导航菜单 */
        .desktop-nav {
            display: flex;
            align-items: center;
        }

        .nav-item {
            position: relative;
            margin: 0 15px;
        }

        .nav-link {
            text-decoration: none;
            color: var(--dark-color);
            font-weight: bold-;
            font-size: 16px;
            padding: 10px 15px;
            display: block;
            transition: var(--transition);
            position: relative;
        }

        .nav-link:hover {
            color: var(--light-color);
            background-color: var(--primary-color);
            border-radius: 0px;
        }

        .nav-link i {
            margin-left: 5px;
            font-size: 12px;
        }

        /* 下拉菜单样式 */
        .dropdown-menu {
            position: absolute;
            top: 149%;
            left: 0;
            width: 200px;
            background-color: var(--light-color);
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            border-radius: 0px;
            opacity: 0;
            visibility: hidden;
            transform: translateY(10px);
            transition: var(--transition);
            z-index: 100;
        }

        .nav-item:hover .dropdown-menu {
            opacity: 1;
            visibility: visible;
            transform: translateY(0);
        }

        .dropdown-item {
            padding: 10px 15px;
            border-bottom: 1px solid var(--gray-color);
        }

        .dropdown-item:last-child {
            border-bottom: none;
        }

        .dropdown-link {
            text-decoration: none;
            color: var(--dark-color);
            display: block;
            transition: var(--transition);
            font-size: 14px;
        }

        .dropdown-link:hover {
            color: var(--primary-color);
            padding-left: 5px;
        }

        /* 移动端菜单按钮 */
        .mobile-menu-btn {
            display: none;
            background: none;
            border: none;
            cursor: pointer;
            padding: 8px;
        }

        .hamburger {
            display: block;
            width: 30px;
            height: 3px;
            background-color: var(--dark-color);
            position: relative;
            transition: var(--transition);
        }

        .hamburger::before,
        .hamburger::after {
            content: '';
            position: absolute;
            width: 30px;
            height: 3px;
            background-color: var(--dark-color);
            left: 0;
            transition: var(--transition);
        }

        .hamburger::before {
            top: -8px;
        }

        .hamburger::after {
            top: 8px;
        }

        /* 移动端菜单样式 */
        .mobile-nav {
            position: fixed;
            top: 0;
            right: -100%;
            width: 80%;
            max-width: 300px;
            height: 100vh;
            background-color: var(--light-color);
            box-shadow: -5px 0 15px rgba(0,0,0,0.1);
            z-index: 1001;
            transition: var(--transition);
            overflow-y: auto;
        }

        .mobile-nav.active {
            right: 0;
        }

        .mobile-nav-header {
            padding: 20px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            border-bottom: 1px solid var(--gray-color);
        }

        .close-btn {
            background: none;
            border: none;
            font-size: 24px;
            cursor: pointer;
            color: #777;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background-color: #eee;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: var(--transition);
        }

        .close-btn:hover {
            background-color: #ddd;
        }

        .header_menu-nav-list {
            list-style: none;
            padding: 10px 0;
        }

        .header_menu-nav-item {
            border-bottom: 1px solid var(--gray-color);
        }

        .header_menu-nav-link {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px 20px;
            text-decoration: none;
            color: var(--dark-color);
            font-weight: bold;
            transition: var(--transition);
        }

        .header_menu-nav-link:hover {
            background-color: var(--gray-color);
        }

        .header_menu-arrow {
            transition: var(--transition);
        }

        .header_menu-nav-item.active .header_menu-arrow {
            transform: rotate(180deg);
        }

        .header_menu-dropdown {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease;
            background-color: #f9f9f9;
        }

        .header_menu-nav-item.active .header_menu-dropdown {
            max-height: 500px;
        }

        .header_menu-dropdown-item {
            padding: 10px 20px 10px 30px;
            border-bottom: 1px solid #eee;
        }

        .header_menu-dropdown-link {
            text-decoration: none;
            color: #666;
            display: block;
            transition: var(--transition);
            font-size: 14px;
        }

        .header_menu-dropdown-link:hover {
            color: var(--primary-color);
        }

        /* 滚动时隐藏顶部栏 */
        body.scrolled .header_top {
            transform: translateY(-100%);
            opacity: 0;
        }

        /* 响应式设计 */
        @media (max-width: 992px) {
            .desktop-nav {
                display: none;
            }
            
            .mobile-menu-btn {
                display: block;
            }
        }