/* --- 全局变量 --- */
        :root {
            --primary-color: #F37021;
            --hover-color: #d95e16;
            --text-color: #333;
            --bg-light: #f4f4f4;
            --white: #ffffff;
            --border-color: #ddd;
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            margin: 0;
            padding: 0;
            background-color: var(--bg-light);
            color: var(--text-color);
        }

        a { text-decoration: none; color: inherit; }

        /* --- 顶部栏 --- */
        header {
            background-color: var(--white);
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
            position: sticky;
            top: 0;
            z-index: 1000;
        }

        .top-bar {
            background-color: #222;
            color: var(--white);
            padding: 8px 20px;
            display: flex;
            justify-content: flex-end;
            font-size: 0.9em;
        }

        .lang-selector { position: relative; cursor: pointer; padding: 0 10px; }
        .lang-selector:hover .lang-dropdown { display: block; }
        .current-lang::after { content: ' ▼'; font-size: 0.8em; }

        .lang-dropdown {
            display: none;
            position: absolute;
            right: 0;
            top: 100%;
            background-color: #333;
            list-style: none;
            margin: 0;
            padding: 0;
            min-width: 150px;
            z-index: 1001;
            box-shadow: 0 4px 6px rgba(0,0,0,0.3);
        }

        .lang-dropdown li a {
            display: block;
            padding: 10px 15px;
            color: #ccc;
            border-bottom: 1px solid #444;
        }
        .lang-dropdown li a:hover { background-color: var(--primary-color); color: var(--white); }

        /* --- 主菜单栏 --- */
        .main-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 0 40px;
            height: 80px;
            position: relative;
        }

        .logo {
            font-size: 28px;
            font-weight: bold;
            color: var(--primary-color);
            display: flex;
            align-items: center;
            z-index: 1002; /* 确保Logo在移动端菜单之上 */
        }
        .logo span { color: #333; margin-left: 10px; font-size: 18px; font-weight: normal; }

        /* 桌面端导航样式 */
        .nav-menu { display: flex; height: 100%; align-items: center; }
        .nav-item { position: relative; height: 100%; display: flex; align-items: center; }
        .nav-link {
            padding: 0 20px;
            font-weight: 600;
            font-size: 16px;
            height: 100%;
            display: flex;
            align-items: center;
            transition: color 0.3s;
            cursor: pointer;
            white-space: nowrap; /* 防止文字换行 */
        }
        .nav-link:hover { color: var(--primary-color); }

        /* 下拉菜单 (Desktop) */
        .dropdown-menu {
            display: none; /* 默认隐藏 */
            position: absolute;
            top: 80px;
            left: 50%;
            transform: translateX(-50%);
            background-color: var(--white);
            box-shadow: 0 5px 15px rgba(0,0,0,0.1);
            width: 600px;
            border-top: 2px solid var(--primary-color);
            padding: 20px;
            z-index: 999;
        }
        
        /* 桌面端 Hover 显示 */
        @media (min-width: 769px) {
            .nav-item:hover .dropdown-menu { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
            .nav-item:hover .nav-link { border-bottom: 3px solid var(--primary-color); }
        }

        .product-group {
            border: 1px solid #eee;
            border-radius: 4px;
            padding: 10px;
            transition: all 0.2s;
            background: #fff;
        }
        .product-group:hover { border-color: var(--primary-color); background-color: #fffaf5; }
        .product-title { font-weight: bold; color: #222; margin-bottom: 8px; display: block; font-size: 16px; border-bottom: 1px solid #eee; padding-bottom: 5px; }
        .product-links { display: flex; gap: 10px; font-size: 12px; color: #666; flex-wrap: wrap; }
        .product-links a:hover { color: var(--primary-color); text-decoration: underline; }

        /* --- 汉堡菜单按钮 (默认隐藏) --- */
        .mobile-menu-toggle {
            display: none;
            font-size: 28px;
            cursor: pointer;
            color: #333;
            z-index: 1002;
        }

        /* --- 移动端响应式布局 (Mobile Styles) --- */
        @media (max-width: 768px) {
            .main-header { padding: 0 20px; height: 60px; }
            .logo { font-size: 22px; }
            .logo span { font-size: 14px; margin-left: 5px; }
            .mobile-menu-toggle { display: block; } /* 显示汉堡按钮 */

            /* 移动端菜单容器 */
            .nav-menu {
                display: none; /* 默认关闭 */
                position: fixed;
                top: 96px; /* Header高度 + TopBar高度的大概值 */
                left: 0;
                width: 100%;
                height: calc(100vh - 96px);
                background-color: var(--white);
                flex-direction: column;
                align-items: flex-start;
                padding: 0;
                overflow-y: auto; /* 允许菜单过长时滚动 */
                box-shadow: 0 5px 10px rgba(0,0,0,0.1);
            }

            /* 菜单打开时的状态 */
            .nav-menu.active { display: flex; }

            .nav-item {
                width: 100%;
                height: auto;
                flex-direction: column;
                align-items: flex-start;
                border-bottom: 1px solid #eee;
            }

            .nav-link {
                width: 100%;
                height: 50px; /* 增加点击区域 */
                justify-content: space-between; /* 文字靠左，箭头靠右 */
                padding: 0 20px;
                box-sizing: border-box;
            }
            
            /* 在移动端添加一个下箭头指示 */
            .nav-link::after {
                content: '+';
                font-size: 18px;
                color: #999;
            }

            /* 移动端下拉菜单样式重置 */
            .dropdown-menu {
                position: static; /* 不再绝对定位 */
                width: 100%;
                transform: none;
                box-shadow: none;
                border-top: none;
                padding: 0;
                background-color: #f9f9f9;
                display: none; /* JS 控制显示 */
                grid-template-columns: 1fr !important; /* 强制单列 */
                gap: 0;
            }
            
            .dropdown-menu.show { display: block; }

            .product-group {
                border: none;
                border-bottom: 1px solid #e0e0e0;
                border-radius: 0;
                padding: 15px 30px; /* 增加缩进 */
                background: transparent;
            }
        }

        /* --- 内容区域 --- */
        .hero-section {
            background: linear-gradient(135deg, #2c3e50 0%, #000 100%);
            color: white;
            padding: 60px 20px;
            text-align: center;
        }
        .hero-section h1 { font-size: 2em; margin-bottom: 15px; text-transform: uppercase; letter-spacing: 1px; }
        .hero-section span { color: var(--primary-color); }

        .content-container {
            max-width: 1200px;
            margin: 30px auto;
            padding: 20px;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 20px;
        }
        .card {
            background: white;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
            border-left: 4px solid var(--primary-color);
        }/* --- 固件弹窗样式 (Modal Styles) --- */
.modal {
    display: none; /* 默认隐藏 */
    position: fixed;
    z-index: 2000; /* 保证在最上层 */
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.5); /* 半透明黑色背景 */
    animation: fadeIn 0.3s;
}

.modal-content {
    background-color: #fff;
    margin: 10% auto; /* 距顶部10%，水平居中 */
    padding: 0;
    border-radius: 8px;
    width: 90%;
    max-width: 500px; /* 最大宽度 */
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
    position: relative;
}

.modal-header {
    padding: 15px 20px;
    border-bottom: 1px solid #eee;
    background-color: var(--primary-color);
    color: white;
    border-radius: 8px 8px 0 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.close-btn {
    color: white;
    font-size: 24px;
    font-weight: bold;
    cursor: pointer;
}
.close-btn:hover { color: #eee; }

.modal-body {
    padding: 20px;
}

/* 固件列表样式 */
.firmware-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px;
    border-bottom: 1px solid #f0f0f0;
}
.firmware-item:last-child { border-bottom: none; }

.fw-info { display: flex; flex-direction: column; }
.fw-version { font-weight: bold; color: #333; }
.fw-date { font-size: 12px; color: #888; margin-top: 4px; }

.fw-download-btn {
    background-color: #eee;
    color: #333;
    padding: 6px 15px;
    border-radius: 4px;
    font-size: 13px;
    transition: all 0.2s;
}
.fw-download-btn:hover {
    background-color: var(--primary-color);
    color: white;
}
/* --- CSS 样式部分 --- */

    /* 1. 提交按钮的样式 */
    .submit-btn {
        background-color: #007bff; /* 蓝色背景 */
        color: white;
        padding: 12px 30px;
        border: none;
        border-radius: 5px;
        cursor: pointer;
        font-size: 16px;
    }
    .submit-btn:hover {
        background-color: #0056b3;
    }

    /* 2. 弹窗背景 (默认隐藏) */
    .modal {
        display: none; /* 默认不显示 */
        position: fixed; 
        z-index: 1000; /* 保证在最上层 */
        left: 0;
        top: 0;
        width: 100%; 
        height: 100%; 
        overflow: auto; 
        background-color: rgba(0,0,0,0.5); /* 半透明黑色背景 */
    }

    /* 3. 弹窗内容框 */
    .modal-content {
        background-color: #fefefe;
        margin: 15% auto; /* 距离顶部15%，水平居中 */
        padding: 25px;
        border: 1px solid #888;
        width: 90%;
        max-width: 450px; /* 最大宽度 */
        border-radius: 8px;
        box-shadow: 0 4px 8px rgba(0,0,0,0.2);
        text-align: center;
        font-family: Arial, sans-serif;
    }

    /* 关闭按钮 (X) */
    .close {
        color: #aaa;
        float: right;
        font-size: 28px;
        font-weight: bold;
        cursor: pointer;
    }
    .close:hover,
    .close:focus {
        color: black;
        text-decoration: none;
        cursor: pointer;
    }

    /* 联系方式列表样式 */
    .contact-list {
        list-style: none;
        padding: 0;
        margin-top: 20px;
    }
    .contact-list li {
        margin: 15px 0;
        font-size: 16px;
    }
    /* 链接样式 */
    .contact-link {
        text-decoration: none;
        color: #333;
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 10px;
        padding: 10px;
        background-color: #f9f9f9;
        border-radius: 5px;
        transition: background 0.2s;
    }
    .contact-link:hover {
        background-color: #e9ecef;
        color: #007bff;
    }