/* ==========================================================================
           1. 全局极简复位与核心变量 (炭黑 #111 & 极简灰 #444)
           ========================================================================== */
        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        :root {
            --text-dark: #111111;   /* 炭黑 */
            --text-muted: #444444;  /* 极简灰 */
            --border-light: #eeeeee;
            --bg-light: #f9f9f9;
            --white: #ffffff;
            --img-bg: #f0f0f0;      /* 图片占位底色 */
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
            color: var(--text-dark);
            background-color: var(--white);
            line-height: 1.6;
        }

        /* Top Info Bar */
        .top-bar {
            background-color: var(--text-dark);
            color: var(--white);
            font-size: 15px;
            padding: 8px 5%;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .top-bar-left span {
            margin-right: 20px;
        }
        .top-bar-right a {
            color: #ffffff;
            text-decoration: underline;
        }

        /* ==========================================================================
           2. 纯 CSS 响应式导航结构
           ========================================================================== */
        header {
            background-color: var(--white);
            border-bottom: 1px solid var(--border-light);
            position: sticky;
            top: 0;
            z-index: 1000;
        }
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            max-width: 1200px;
            margin: 0 auto;
            padding: 18px 24px;
            position: relative;
        }
        .logo a {
            font-size: 20px;
            font-weight: 700;
            color: var(--text-dark);
            text-decoration: none;
            letter-spacing: 0.5px;
            display: inline-flex;
            align-items: center;
        }
        .logo span {
            font-size: 20px;
            font-weight: 700;
            margin-left: 4px;
            letter-spacing: 0.5px;
        }

        #menu-toggle {
            display: none;
        }

        nav ul {
            display: flex;
            list-style: none;
            align-items: center;
        }
        nav ul li {
            margin-left: 28px;
        }
        nav ul li a {
            text-decoration: none;
            color: var(--text-muted);
            font-weight: 500;
            font-size: 15px;
            transition: color 0.2s ease;
        }
        nav ul li a:hover {
            color: var(--text-dark);
        }
        .btn-rfq {
            background-color: var(--text-dark);
            color: var(--white) !important;
            padding: 10px 20px;
            border-radius: 4px;
            font-size: 14px;
            font-weight: 600;
        }

        .hamburger-icon {
            display: none;
            flex-direction: column;
            justify-content: space-between;
            width: 24px;
            height: 16px;
            cursor: pointer;
            z-index: 1005;
        }
        .hamburger-icon span {
            width: 100%;
            height: 2px;
            background-color: var(--text-dark);
            transition: transform 0.3s ease, opacity 0.3s ease;
        }

        /* ==========================================================================
           3. 页面公共版块与图片占位通用样式 (Lazy Load Placeholder)
           ========================================================================== */
        section {
            padding: 80px 24px;
        }
        .container {
            max-width: 1200px;
            margin: 0 auto;
        }
        .section-title {
            text-align: center;
            margin-bottom: 50px;
        }
        .section-title h2 {
            font-size: 32px;
            font-weight: 700;
            color: var(--text-dark);
            margin-bottom: 12px;
        }
        .section-title p {
            color: var(--text-muted);
            font-size: 16px;
        }

        /* 标准化图片占位容器 */
        .img-placeholder {
            background-color: var(--img-bg);
            position: relative;
            display: block;
            width: 100%;
            overflow: hidden;
        }
        /* 预留懒加载图片样式 */
        .img-placeholder img {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            object-fit: cover;
            border: 0;
        }
        /* 未加载出图片时的文字提示 */
        .img-tip {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            font-size: 13px;
            color: #999999;
            white-space: nowrap;
            pointer-events: none;
            z-index: 1;
        }

        /* Hero Showcase */
        .hero {
            background-color: var(--bg-light);
            text-align: center;
            padding: 100px 24px;
        }
        .hero h1 {
            font-size: 46px;
            font-weight: 800;
            line-height: 1.2;
            margin-bottom: 20px;
        }
        .hero p {
            font-size: 18px;
            color: var(--text-muted);
            max-width: 750px;
            margin: 0 auto 35px auto;
        }
        .hero-badges {
            display: flex;
            justify-content: center;
            gap: 15px;
            flex-wrap: wrap;
        }
        .hero-cta {
            display: inline-block;
            background-color: var(--text-dark);
            color: var(--white);
            text-decoration: none;
            padding: 14px 40px;
            font-size: 16px;
            font-weight: 600;
            border-radius: 4px;
            margin-top: 30px;
            transition: background-color 0.2s ease;
        }
        .hero-cta:hover {
            background-color: #333333;
        }
        .badge {
            background: #ffffff;
            border: 1px solid #dddddd;
            padding: 8px 16px;
            font-size: 14px;
            font-weight: 500;
            border-radius: 4px;
        }

        /* About Factory */
        .about-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 50px;
            align-items: center;
        }
        .about-text h3 {
            font-size: 26px;
            margin-bottom: 20px;
        }
        .about-text p {
            color: var(--text-muted);
            margin-bottom: 15px;
            text-align: justify;
        }
        .stats-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 20px;
        }
        .stat-box {
            background: var(--bg-light);
            padding: 30px;
            border-radius: 4px;
            text-align: center;
        }
        .stat-box .num {
            font-size: 32px;
            font-weight: 700;
            color: var(--text-dark);
            margin-bottom: 5px;
        }
        .stat-box .label {
            font-size: 13px;
            color: var(--text-muted);
        }

        /* ==========================================================================
           4. 证书版块升级：精准预留图片占位 (匹配 image_65e6a4.png)
           ========================================================================== */
        .cert-section {
            background-color: var(--bg-light);
        }
        .cert-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 30px;
        }
        .cert-card {
            background: var(--white);
            border: 1px solid var(--border-light);
            padding: 30px 30px 24px 30px;
            border-radius: 6px;
            text-align: center;
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        .cert-card h3 {
            font-size: 20px;
            margin-bottom: 10px;
            color: var(--text-dark);
        }
        .cert-card p {
            font-size: 14px;
            color: var(--text-muted);
            margin-bottom: 20px;
            flex-grow: 1;
        }
        /* 证书图片宽度铺满、高度等比例 */
        .cert-card .img-placeholder {
            width: 100%;
            height: auto;
            border-radius: 4px;
            border: 1px solid transparent;
        }
        .cert-card .img-placeholder img {
            position: relative;
            width: 100%;
            height: auto;
            object-fit: initial;
        }
        /* 隐藏证书和产品卡片的占位提示文字 */
        .cert-card .img-tip,
        .product-card .img-tip {
            display: none;
        }

        /* ==========================================================================
           5. 17类花边大目录产品栅格布局 (内置延迟懒加载结构)
           ========================================================================== */
        .catalog-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 30px;
        }
        .product-card {
            border: 1px solid var(--border-light);
            border-radius: 4px;
            overflow: hidden;
            background: var(--white);
            display: flex;
            flex-direction: column;
        }
        .product-card .img-placeholder {
            height: 220px;
        }
        .product-info {
            padding: 24px;
            flex: 1;
            display: flex;
            flex-direction: column;
        }
        .product-info h3 {
            font-size: 18px;
            margin-bottom: 12px;
            color: var(--text-dark);
        }
        .product-info p {
            font-size: 14px;
            color: var(--text-muted);
            margin-bottom: 15px;
            height: 44px;
            overflow: hidden;
        }
        /* 极简无边框表格样式 */
        .spec-table {
            width: 100%;
            border-collapse: collapse;
            font-size: 13px;
            margin-bottom: 15px;
            margin-top: auto;
        }
        .spec-table td {
            padding: 6px 0;
            border-bottom: 1px dashed #f0f0f0;
        }
        .spec-table td:first-child {
            color: #888888;
        }
        .spec-table td:last-child {
            text-align: right;
            font-weight: 600;
        }
        .card-btn {
            display: block;
            text-align: center;
            background: var(--text-dark);
            color: var(--white);
            text-decoration: none;
            padding: 10px;
            font-size: 13px;
            font-weight: 500;
            border-radius: 4px;
        }

        /* RFQ Form */
        .rfq-section {
            background-color: var(--bg-light);
        }
        .rfq-container {
            max-width: 600px;
            margin: 0 auto;
            background: var(--white);
            padding: 40px;
            border-radius: 6px;
            border: 1px solid var(--border-light);
        }
        .form-group {
            margin-bottom: 20px;
        }
        .form-group label {
            display: block;
            font-size: 13px;
            font-weight: 600;
            margin-bottom: 8px;
        }
        .form-control {
            width: 100%;
            padding: 12px;
            border: 1px solid #cccccc;
            border-radius: 4px;
            font-size: 14px;
        }
        .btn-submit {
            width: 100%;
            background: var(--text-dark);
            color: var(--white);
            border: none;
            padding: 14px;
            font-size: 15px;
            font-weight: 600;
            border-radius: 4px;
            cursor: pointer;
        }

        /* Footer & Social */
        footer {
            background: var(--text-dark);
            color: #999999;
            padding: 60px 24px 30px 24px;
            font-size: 14px;
        }
        .footer-grid {
            max-width: 1200px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: 2fr 1fr 2fr;
            gap: 40px;
            border-bottom: 1px solid #222222;
            padding-bottom: 40px;
            margin-bottom: 30px;
        }
        .footer-col h4 {
            color: var(--white);
            margin-bottom: 15px;
        }
        .footer-col p {
            line-height: 1.5;
        }

        .social-container {
            display: flex;
            gap: 14px;
            margin-top: 20px;
        }
        .social-icon {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 38px;
            height: 38px;
            border-radius: 50%;
            background-color: rgba(255, 255, 255, 0.08);
            transition: background-color 0.2s ease, transform 0.2s ease;
        }
        .social-icon:hover {
            background-color: rgba(255, 255, 255, 0.18);
            transform: translateY(-2px);
        }
        .social-icon svg {
            width: 18px;
            height: 18px;
            fill: #ffffff;
        }

        /* WhatsApp Float Component */
        .whatsapp-float {
            position: fixed;
            bottom: 30px;
            right: 30px;
            background-color: var(--text-dark);
            color: var(--white);
            padding: 12px 20px;
            border-radius: 4px;
            text-decoration: none;
            font-size: 14px;
            font-weight: 600;
            letter-spacing: 0.5px;
            box-shadow: 0 4px 15px rgba(0,0,0,0.15);
            z-index: 9999;
            display: flex;
            align-items: center;
            gap: 8px;
            transition: background-color 0.2s ease, transform 0.2s ease;
        }
        .whatsapp-float:hover {
            background-color: #333333;
            transform: translateY(-2px);
        }

        /* 📱 移动端自适应 */
        @media (max-width: 991px) {
            .hamburger-icon {
                display: flex;
            }
            nav {
                display: none;
                position: absolute;
                top: 100%;
                left: 0;
                width: 100%;
                background-color: var(--white);
                box-shadow: 0 10px 20px rgba(0,0,0,0.05);
                border-top: 1px solid var(--border-light);
                padding: 10px 0 24px 0;
                z-index: 1001;
            }
            nav ul {
                flex-direction: column;
                align-items: stretch;
            }
            nav ul li {
                margin: 0;
            }
            nav ul li a {
                display: block;
                padding: 14px 24px;
                font-size: 16px;
                border-bottom: 1px solid #fafafa;
            }
            .btn-rfq {
                margin: 16px 24px 0 24px;
                text-align: center;
            }

            #menu-toggle:checked ~ nav {
                display: block !important;
            }
            #menu-toggle:checked ~ .hamburger-icon span:nth-child(1) {
                transform: rotate(45deg) translate(4px, 4px);
            }
            #menu-toggle:checked ~ .hamburger-icon span:nth-child(2) {
                opacity: 0;
            }
            #menu-toggle:checked ~ .hamburger-icon span:nth-child(3) {
                transform: rotate(-45deg) translate(5px, -6px);
            }

            .about-grid, .cert-grid, .catalog-grid {
                grid-template-columns: 1fr;
            }
            .footer-grid {
                grid-template-columns: 1fr;
            }
            .hero h1 {
                font-size: 30px;
            }
            .whatsapp-float {
                bottom: 20px;
                right: 20px;
                padding: 10px 16px;
                font-size: 13px;
            }
        }