/* roulang page: index */
:root {
            --primary: #E85D04;
            --primary-hover: #D14D02;
            --secondary: #1A1A2E;
            --bg-light: #F5F7FA;
            --card-bg: #FFFFFF;
            --accent-blue: #2B6CB0;
            --success: #10B981;
            --text-body: #4A5568;
            --text-muted: #718096;
            --border-radius: 12px;
            --btn-radius: 8px;
            --card-shadow: 0 2px 12px rgba(0,0,0,0.06);
            --card-shadow-hover: 0 8px 24px rgba(0,0,0,0.10);
            --section-padding: 80px 0;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
            font-size: 16px;
            line-height: 26px;
            color: var(--text-body);
            background-color: var(--bg-light);
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

        img {
            max-width: 100%;
            height: auto;
            display: block;
        }

        a {
            text-decoration: none;
            color: inherit;
            transition: color 0.25s ease;
        }

        button {
            font-family: inherit;
            cursor: pointer;
            border: none;
            outline: none;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 24px;
        }

        /* 导航 */
        header {
            background: #fff;
            position: sticky;
            top: 0;
            z-index: 1000;
            box-shadow: 0 1px 0 rgba(0,0,0,0.05);
            transition: box-shadow 0.3s ease;
        }
        header.scrolled {
            box-shadow: 0 2px 12px rgba(0,0,0,0.08);
        }
        .nav-container {
            display: flex;
            align-items: center;
            justify-content: space-between;
            height: 72px;
        }
        .logo-group {
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .logo-icon {
            width: 36px;
            height: 36px;
            background: var(--primary);
            border-radius: 8px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: #fff;
            font-size: 22px;
            font-weight: 700;
        }
        .logo-text {
            font-size: 22px;
            font-weight: 700;
            color: var(--secondary);
            letter-spacing: 1px;
        }
        nav ul {
            display: flex;
            list-style: none;
            gap: 32px;
        }
        nav ul li a {
            font-size: 16px;
            font-weight: 500;
            color: var(--text-body);
            position: relative;
            padding: 8px 0;
            transition: color 0.25s ease;
        }
        nav ul li a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0%;
            height: 2px;
            background: var(--primary);
            transition: width 0.25s ease;
        }
        nav ul li a:hover,
        nav ul li a.active {
            color: var(--primary);
        }
        nav ul li a:hover::after,
        nav ul li a.active::after {
            width: 100%;
        }
        .hamburger {
            display: none;
            flex-direction: column;
            justify-content: space-between;
            width: 40px;
            height: 40px;
            background: var(--secondary);
            border-radius: 8px;
            padding: 12px 10px;
            cursor: pointer;
        }
        .hamburger span {
            display: block;
            height: 2px;
            background: #fff;
            border-radius: 1px;
        }
        .mobile-menu {
            position: fixed;
            top: 72px;
            left: 0;
            width: 100%;
            height: calc(100vh - 72px);
            background: #fff;
            transform: translateX(-100%);
            transition: transform 0.35s ease;
            z-index: 999;
            padding: 24px;
            display: flex;
            flex-direction: column;
            gap: 8px;
        }
        .mobile-menu.open {
            transform: translateX(0);
        }
        .mobile-menu a {
            display: block;
            padding: 16px 24px;
            font-size: 18px;
            font-weight: 500;
            color: var(--secondary);
            border-radius: var(--btn-radius);
            transition: all 0.2s ease;
        }
        .mobile-menu a:hover {
            background: var(--primary);
            color: #fff;
        }

        /* 区块标题公用 */
        .section-intro {
            text-align: center;
            margin-bottom: 56px;
        }
        h2 {
            font-size: 32px;
            font-weight: 600;
            color: var(--secondary);
            line-height: 40px;
            margin-bottom: 16px;
            text-align: center;
        }
        .section-subtitle {
            font-size: 18px;
            color: var(--text-muted);
            line-height: 30px;
        }

        /* 按钮 */
        .btn {
            display: inline-block;
            padding: 14px 32px;
            font-size: 16px;
            font-weight: 600;
            border-radius: var(--btn-radius);
            transition: all 0.3s ease;
            text-align: center;
        }
        .btn-primary {
            background: var(--primary);
            color: #fff;
        }
        .btn-primary:hover {
            background: var(--primary-hover);
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(232,93,4,0.3);
        }
        .btn-outline {
            background: transparent;
            color: var(--accent-blue);
            border: 1.5px solid var(--accent-blue);
        }
        .btn-outline:hover {
            background: rgba(43,108,176,0.08);
            transform: translateY(-2px);
        }

        /* Hero */
        .hero {
            padding: var(--section-padding);
            background: #fff;
        }
        .hero .container {
            display: flex;
            align-items: center;
            gap: 60px;
        }
        .hero-content {
            flex: 1;
        }
        .hero h1 {
            font-size: 44px;
            font-weight: 700;
            color: var(--secondary);
            line-height: 56px;
            margin-bottom: 20px;
            text-align: left;
        }
        .hero-sub {
            font-size: 18px;
            color: var(--text-body);
            line-height: 30px;
            margin-bottom: 40px;
            max-width: 500px;
        }
        .hero-btns {
            display: flex;
            gap: 20px;
            flex-wrap: wrap;
        }
        .hero-image {
            flex: 1;
            position: relative;
        }
        .hero-image img {
            width: 100%;
            border-radius: 16px;
            box-shadow: var(--card-shadow);
        }
        .hero-image::after {
            content: '';
            position: absolute;
            top: 0; right: 0; bottom: 0; left: 0;
            background: linear-gradient(transparent, rgba(232,93,4,0.08));
            border-radius: 16px;
            pointer-events: none;
        }

        /* 亮点网格 3x2 非对称 */
        .features {
            padding: var(--section-padding);
        }
        .grid-3x2 {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            grid-template-rows: auto;
            gap: 24px;
        }
        .feat-card {
            background: var(--card-bg);
            border-radius: var(--border-radius);
            padding: 32px;
            box-shadow: var(--card-shadow);
            transition: all 0.25s ease;
            display: flex;
            flex-direction: column;
            justify-content: flex-start;
        }
        .feat-card:hover {
            box-shadow: var(--card-shadow-hover);
            transform: translateY(-4px);
        }
        .feat-icon {
            width: 48px; height: 48px;
            background: rgba(43,108,176,0.1);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 28px;
            color: var(--accent-blue);
            margin-bottom: 20px;
            transition: background 0.3s;
        }
        .feat-card:hover .feat-icon {
            background: rgba(232,93,4,0.1);
            color: var(--primary);
        }
        .feat-card h3 {
            font-size: 20px;
            font-weight: 600;
            color: var(--secondary);
            line-height: 28px;
            margin-bottom: 8px;
        }
        .feat-card p {
            font-size: 14px;
            color: var(--text-muted);
            line-height: 22px;
        }
        /* 破除非对称 grid: 某些卡片跨列 */
        .grid-3x2 .feat-card:nth-child(1) { grid-column: span 2; }
        .grid-3x2 .feat-card:nth-child(2) { grid-column: span 1; }
        .grid-3x2 .feat-card:nth-child(3) { grid-column: span 1; }
        .grid-3x2 .feat-card:nth-child(4) { grid-column: span 1; }
        .grid-3x2 .feat-card:nth-child(5) { grid-column: span 1; }
        .grid-3x2 .feat-card:nth-child(6) { grid-column: span 2; }

        /* 案例瀑布流 */
        .cases {
            padding: var(--section-padding);
            background: #fff;
        }
        .masonry {
            columns: 3;
            column-gap: 24px;
            break-inside: avoid;
        }
        .case-card {
            background: var(--card-bg);
            border-radius: var(--border-radius);
            box-shadow: var(--card-shadow);
            overflow: hidden;
            transition: all 0.25s ease;
            margin-bottom: 24px;
            display: inline-block;
            width: 100%;
        }
        .case-card:hover {
            box-shadow: var(--card-shadow-hover);
            transform: translateY(-4px);
        }
        .case-image {
            width: 100%;
            aspect-ratio: 4/3;
            object-fit: cover;
        }
        .case-info {
            padding: 16px;
        }
        .case-tag {
            display: inline-block;
            background: rgba(232,93,4,0.12);
            color: var(--primary);
            font-size: 12px;
            font-weight: 600;
            padding: 4px 12px;
            border-radius: 20px;
            margin-bottom: 8px;
            text-transform: uppercase;
            letter-spacing: 0.5px;
        }
        .case-title {
            font-size: 18px;
            font-weight: 600;
            color: var(--secondary);
            margin-bottom: 4px;
        }
        .case-desc {
            font-size: 14px;
            color: var(--text-muted);
            line-height: 22px;
        }

        /* 方案对比 */
        .comparison {
            padding: var(--section-padding);
        }
        .compare-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 0;
            border-radius: var(--border-radius);
            overflow: hidden;
            box-shadow: var(--card-shadow);
            background: #fff;
        }
        .compare-col {
            padding: 40px 32px;
        }
        .compare-col-left {
            background: #EDF2F7;
        }
        .compare-col-right {
            background: #fff;
            position: relative;
        }
        .compare-col-right::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 4px;
            height: 100%;
            background: var(--primary);
            border-radius: 0 4px 4px 0;
        }
        .compare-h {
            font-size: 22px;
            font-weight: 700;
            margin-bottom: 28px;
            color: var(--secondary);
        }
        .compare-row {
            display: flex;
            align-items: center;
            gap: 14px;
            margin-bottom: 24px;
            font-size: 16px;
            color: var(--text-body);
            line-height: 1.5;
        }
        .compare-row .check-icon {
            color: var(--success);
            font-size: 20px;
            margin-right: 6px;
            flex-shrink: 0;
        }
        .compare-row .negative {
            opacity: 0.6;
        }

        /* FAQ */
        .faq {
            padding: var(--section-padding);
            background: #fff;
        }
        .accordion {
            max-width: 800px;
            margin: 40px auto 0;
        }
        .accordion-item {
            margin-bottom: 20px;
            border-left: 5px solid transparent;
            background: #F0F4FF;
            border-radius: var(--border-radius);
            transition: all 0.3s ease;
            overflow: hidden;
        }
        .accordion-item.active {
            border-left-color: var(--accent-blue);
            background: #F0F4FF;
        }
        .accordion-toggle {
            width: 100%;
            padding: 24px 24px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            text-align: left;
            font-size: 18px;
            font-weight: 600;
            color: var(--secondary);
            background: transparent;
            transition: 0.2s;
        }
        .accordion-toggle span {
            flex-grow: 1;
        }
        .accordion-toggle .icon {
            font-size: 24px;
            color: var(--primary);
            transition: transform 0..3s;
            transform: rotate(0deg);
        }
        .accordion-item.active .icon {
            transform: rotate(45deg);
        }
        .accordion-content {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.35s ease, padding 0.35s;
            padding: 0 24px;
        }
        .accordion-item.active .accordion-content {
            max-height: 250px;
            padding-bottom: 24px;
        }
        .accordion-content p {
            color: var(--text-body);
            font-size: 16px;
            line-height: 26px;
        }

        /* CTA Banner */
        .cta-banner {
            background: #EBF4FF;
            padding: 60px 24px;
            text-align: center;
            border-radius: 16px;
            margin: 20px 0 80px;
        }
        .cta-banner h3 {
            font-size: 28px;
            font-weight: 700;
            color: var(--secondary);
            margin-bottom: 20px;
        }
        .cta-sub {
            font-size: 16px;
            color: var(--text-muted);
            margin-top: 12px;
        }

        /* 页脚 */
        .footer {
            background: var(--secondary);
            color: rgba(255,255,255,0.85);
            padding: 60px 0 30px;
        }
        .footer-grid {
            display: grid;
            grid-template-columns: 2fr 1fr 1fr 1fr;
            gap: 40px;
        }
        .footer a:hover {
            color: var(--primary);
        }
        .footer-logo {
            font-size: 24px;
            font-weight: 700;
            color: #fff;
            letter-spacing: 2px;
            margin-bottom: 14px;
        }
        .footer h4 {
            font-weight: 700;
            color: #fff;
            margin-bottom: 16px;
        }
        .footer-link li {
            list-style: none;
            margin-bottom: 10px;
        }
        .copyright {
            border-top: 1px solid rgba(255,255,255,0.1);
            padding-top: 25px;
            margin-top: 40px;
            text-align: center;
            color: rgba(255,255,255,0.6);
            font-size: 15px;
        }