/* 固定顶部导航 */
        .navbar {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            background: #00263b;
            padding: 0 48px;
            height: 80px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            box-shadow: 0 8px 20px rgba(0,20,30,0.6);
            z-index: 2000;
            border-bottom: 2px solid #1f6390;
        }

        .nav-left {
            display: flex;
            gap: 48px;
            height: 100%;
            align-items: center;
        }

        .nav-item {
            cursor: pointer;
            color: white;
            align-items: center;
            transition: 0.15s;
        }

        .nav-item:hover {
            color: #c5e5ff;
        }

        .nav-item.active {
            border-bottom-color:#007aff;
        }

        .nav-right {
            display: flex;
            align-items: center;
            gap: 32px;
        }

        .cooling-tag {
            color: #b0dcff;
            background: rgba(255,255,255,0.08);
            padding: 6px 20px;
            border-radius: 40px;
            border: 1px solid #376e9a;
            font-size: 0.95rem;
        }

        .contact-pill {
            border: 2px solid #5f9acb;
            color: white;
            padding: 8px 30px;
            border-radius: 40px;
            font-weight: 600;
        }

        /* 主内容区域 */
        .main-content {
            margin-top: 100px;
            padding: 20px 40px 40px 40px;
            transition: opacity 0.2s;
        }

        /* 当下拉打开时，主内容半透明 */
        body.menu-open .main-content {
            opacity: 0.4;
            pointer-events: none;
        }

        /* 下拉菜单 - 紧贴导航下方 */
        .dropdown-overlay {
            position: fixed;
            top: 125px;
            left: 0;
            width: 100%;
            background: rgba(10, 30, 50, 0.2);
            backdrop-filter: blur(4px);
            -webkit-backdrop-filter: blur(4px);
            z-index: 1500;
            display: flex;
            justify-content: center;
            align-items: flex-start;
            opacity: 0;
            visibility: hidden;
            transition: opacity 0.25s ease, visibility 0s 0.25s;
            min-height: calc(100vh - 80px);
            padding: 16px 20px 40px 20px;
            overflow-y: auto;
        }

        .dropdown-overlay.active {
            opacity: 1;
            visibility: visible;
            transition: opacity 0.25s ease, visibility 0s 0s;
        }

        /* 下拉卡片 */
        .dropdown-card {
            background: #f8fcff;
            width: calc(100% - 40px);
            border-radius: 16px;
            box-shadow: 0 30px 60px -20px #001a33, 0 0 0 1px rgba(255,255,255,0.6) inset;
            padding: 20px;
            transform: translateY(-10px);
            transition: transform 0.3s cubic-bezier(0.15,1,0.3,1);
            border: 1px solid #bdd2e8;
        }

        .dropdown-overlay.active .dropdown-card {
            transform: translateY(0);
        }

        /* 卡片头部 */
        .dropdown-header {
            display: flex;
            align-items: center;
            justify-content: space-between;
            margin-bottom: 20px;
            /*padding-bottom: 12px;*/
        }

        .dropdown-header h2 {
            font-size: 2.2rem;
            font-weight: 600;
            color: #00263b;
            display: flex;
            align-items: center;
            gap: 18px;
        }

        .dropdown-header h2 span {
            background: #c3dffc;
            padding: 6px 20px;
            border-radius: 60px;
            font-size: 1rem;
            color: #003e6b;
        }

        .close-btn {
            background: white;
            border: none;
            width: 36px;
            height: 36px;
            border-radius: 50%;
            font-size: 28px;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            box-shadow: 0 4px 10px rgba(0, 30, 60, 0.2);
            border: 1px solid #b5cee8;
            transition: 0.15s;
            color: #0f3d60;
        }

        .close-btn:hover {
            background: #e1efff;
            transform: rotate(90deg);
        }

        /* 级联容器 */
        .cascade-container {
            background: #f2f7fd;
            border-radius: 14px;
            padding: 16px;
            min-height: 400px;
            border: 1px solid #c5daf0;
            margin-bottom: 20px;
        }

        /* ========== 电脑端横向级联样式 ========== */
        .desktop-cascade-row {
            display: flex;
            flex-direction: row;
            align-items: flex-start;
            gap: 16px;
            overflow-x: auto;
            padding: 8px;
        }

        .desktop-column {
            background: white;
            border-radius: 12px;
            padding: 16px 0 20px 0;
            width: 400px;
            box-shadow: 0 8px 20px -8px rgba(0,40,70,0.25), 0 0 0 1px #cddcec inset;
        }
.desktop-column:nth-child(2){background: #f5f3f2;}
.desktop-column:nth-child(3){background: #eeeeec;}
.desktop-column:nth-child(2) .desktop-column-header,.desktop-column:nth-child(3) .desktop-column-header{display: none}

        .desktop-column-header {
            font-weight: 700;
            padding: 0 20px 12px 20px;
            color: #1a4d7a;
            border-bottom: 2px solid #dde9f5;
            margin-bottom: 8px;
            text-transform: uppercase;
            letter-spacing: 0.4px;font-size: 12px;
        }

        .desktop-item {
            padding: 5px 15px;
            margin: 2px 8px;
            /*border-radius: 16px;*/
            color: #0b3a5a;
            display: flex;
            align-items: center;
            justify-content: space-between;
            cursor: pointer;
            transition: all 0.2s ease;
            border-left: 3px solid transparent;
            font-size: 12px;
        }

        .desktop-item.has-child::after {
            content: "›";
            line-height: 1;
            color: #2f79b0;
            opacity: 0.7;
            margin-left: 12px;
        }

        .desktop-item:hover {
            background: #d3eaff;
            border-left-color: #0077be;
            padding-left: 26px;
            box-shadow: 0 2px 8px rgba(0,100,200,0.15);
            color: #003a70;
            font-weight: 600;
            transform: translateX(2px);
        }

        .desktop-item:hover.has-child::after {
            opacity: 1;
            transform: translateX(4px);
            color: #004c97;
        }

        /* 路径高亮样式 - 深色块 */
        .desktop-item.path-highlight {
            background: #f5f3f2 !important;
            border-left-color: #0059b3 !important;
            border-left-width: 6px !important;
            box-shadow: 0 4px 12px rgba(0,80,160,0.3) !important;
            color: #002856 !important;
            font-weight: 700 !important;
        }
.desktop-column:nth-child(2) .desktop-item.path-highlight{background: #eeeeec !important;}

        .desktop-item.path-highlight.has-child::after {
            opacity: 1;
            color: #004c97;
            transform: translateX(4px);
        }

        /* ========== 手机端垂直逐级返回样式 ========== */
        .mobile-nav {
            display: flex;
            align-items: center;
            gap: 12px;
            margin-bottom: 16px;
            padding: 8px 12px;
            background: white;
            border-radius: 40px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.05);
        }

        .back-btn {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 36px;
            height: 36px;
            background: #e9f0f7;
            border-radius: 50%;
            color: #003a70;
            font-size: 1.5rem;
            cursor: pointer;
            transition: 0.15s;
            border: 1px solid #b5cee8;
        }

        .back-btn:hover {
            background: #d3e5ff;
        }

        .back-btn.hidden {
            opacity: 0.3;
            pointer-events: none;
        }

        .current-title {
            font-size: 1rem;
            font-weight: 600;
            color: #0077be;
            flex: 1;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        .mobile-item {
            padding: 16px 20px;
            background: white;
            border-radius: 16px;
            font-size: 1.1rem;
            font-weight: 500;
            color: #0b3a5a;
            display: flex;
            align-items: center;
            justify-content: space-between;
            cursor: pointer;
            box-shadow: 0 2px 8px rgba(0,0,0,0.05);
            transition: all 0.2s ease;
            border-left: 4px solid transparent;
            margin-bottom: 4px;
        }

        .mobile-item.has-child::after {
            content: "›";
            font-size: 1.8rem;
            line-height: 1;
            color: #2f79b0;
            opacity: 0.7;
            margin-left: 8px;
        }

        .mobile-item:hover {
            background: #d3eaff;
            border-left-color: #0077be;
            box-shadow: 0 4px 12px rgba(0,100,200,0.2);
            color: #003a70;
            font-weight: 600;
            transform: translateX(2px);
        }

        .mobile-item:hover.has-child::after {
            opacity: 1;
            color: #004c97;
            transform: translateX(4px);
        }

        .mobile-item.path-highlight {
            background: #c0e1ff !important;
            border-left-color: #0059b3 !important;
            border-left-width: 6px !important;
            box-shadow: 0 4px 12px rgba(0,80,160,0.3) !important;
            color: #002856 !important;
            font-weight: 700 !important;
        }

        .mobile-item.path-highlight.has-child::after {
            opacity: 1;
            color: #004c97;
            transform: translateX(4px);
        }

        /* 底部工具区块 */
        .safety-footer {
            background: #e3effb;
            border-radius: 60px;
            padding: 16px 30px;
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 20px;
            border: 1px solid #b1cef0;
        }

        .safety-footer span {
            background: white;
            padding: 8px 28px;
            border-radius: 40px;
            font-weight: 600;
            color: #00325c;
        }

        .safety-footer .product-safety {
            background: #feedb7;
            margin-left: auto;
            border: 1px solid #dcb228;
        }

        .news-area {
            margin-top: 22px;
            padding: 14px 22px;
            background: #d7e7f8;
            border-radius: 60px;
            color: #00356b;
            display: flex;
            gap: 24px;
            flex-wrap: wrap;
        }

        /* ========== 手机端适配 CSS ========== */
        @media screen and (max-width: 768px) {
            .navbar {
                padding: 0 16px;
                height: 60px;
            }

            .nav-left {
                gap: 16px;
            }

            .nav-item {width: 100%;}
            

            .nav-right {
                gap: 8px;
            }


            .cooling-tag {
                display: none;
            }

            .contact-pill {
                padding: 4px 16px;
                font-size: 0.8rem;
                white-space: nowrap;
            }

            .main-content {
                margin-top: 80px;
                padding: 12px 12px 20px 12px;
            }

            .dropdown-overlay {
                top: 60px;
                min-height: calc(100vh - 60px);
                padding: 8px 8px 20px 8px;
            }

            .dropdown-card {
                width: calc(100% - 16px);
                padding: 20px 16px 30px 16px;
            }

            .dropdown-header h2 {
                font-size: 1.4rem;
                gap: 8px;
                flex-wrap: wrap;
            }

            .dropdown-header h2 span {
                padding: 4px 12px;
                font-size: 0.8rem;
            }

            .close-btn {
                width: 40px;
                height: 40px;
                font-size: 24px;
            }

            .safety-footer {
                padding: 12px 16px;
                gap: 10px;
                border-radius: 30px;
                flex-direction: column;
            }

            .safety-footer span {
                padding: 6px 16px;
                font-size: 0.85rem;
                width: 100%;
                text-align: center;
            }

            .safety-footer .product-safety {
                margin-left: 0;
            }

            .news-area {
                padding: 10px 14px;
                gap: 10px;
                font-size: 0.85rem;
                flex-direction: column;
                text-align: center;
            }
        }