/* roulang page: index */
:root {
            --primary: #1e5fbb;
            --primary-deep: #0f3b7a;
            --accent: #f39c12;
            --accent-glow: #e67e22;
            --bg-white: #ffffff;
            --bg-light-gray: #f7f9fc;
            --bg-compare-left: #f0f2f5;
            --bg-compare-right: #e8f0fe;
            --text-primary: #1a1a1a;
            --text-secondary: #5a5a5a;
            --text-muted: #a0aab4;
            --border-light: #eaeaea;
            --border-input: #d0d5dd;
            --radius-card: 16px;
            --radius-btn: 8px;
            --radius-faq: 12px;
            --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
            --shadow-hover: 0 8px 24px rgba(30,95,187,0.12);
            --shadow-btn: 0 4px 12px rgba(30,95,187,0.25);
            --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", "Inter", sans-serif;
            --font-mono: "SF Mono", "Menlo", "Consolas", monospace;
            --transition: 0.2s ease;
            --header-height: 72px;
        }

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

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: var(--font-sans);
            font-size: 16px;
            line-height: 1.7;
            font-weight: 400;
            color: var(--text-primary);
            background-color: var(--bg-white);
            -webkit-font-smoothing: antialiased;
            text-rendering: optimizeLegibility;
        }

        a {
            text-decoration: none;
            color: inherit;
            transition: color var(--transition);
        }

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

        button, input, textarea {
            font-family: inherit;
            font-size: inherit;
        }

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

        /* Header & Navigation */
        #header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: var(--header-height);
            background: rgba(255,255,255,0.92);
            backdrop-filter: blur(10px);
            -webkit-backdrop-filter: blur(10px);
            box-shadow: 0 1px 4px rgba(0,0,0,0.02);
            z-index: 100;
            display: flex;
            align-items: center;
        }

        .header-inner {
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 100%;
        }

        .logo {
            font-size: 24px;
            font-weight: 700;
            letter-spacing: 0.5px;
            color: var(--primary);
            display: flex;
            align-items: center;
            gap: 6px;
        }

        .logo i {
            font-size: 28px;
            color: var(--accent);
        }

        .nav-links {
            display: flex;
            align-items: center;
            gap: 40px;
        }

        .nav-links a {
            font-size: 15px;
            font-weight: 500;
            color: var(--text-primary);
            position: relative;
            padding: 8px 0;
        }

        .nav-links a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--primary);
            transition: width var(--transition);
        }

        .nav-links a:hover::after,
        .nav-links a.active::after {
            width: 100%;
        }

        .nav-links a.active {
            color: var(--primary);
            font-weight: 600;
        }

        .hamburger {
            display: none;
            background: none;
            border: none;
            font-size: 24px;
            color: var(--primary);
            cursor: pointer;
            padding: 8px;
        }

        /* Mobile Nav */
        @media (max-width: 767px) {
            .hamburger {
                display: block;
            }
            .nav-links {
                position: fixed;
                top: var(--header-height);
                left: 0;
                width: 100%;
                height: calc(100vh - var(--header-height));
                background: rgba(255,255,255,0.98);
                backdrop-filter: blur(12px);
                flex-direction: column;
                justify-content: center;
                gap: 28px;
                transform: translateX(100%);
                transition: transform 0.3s ease;
                z-index: 99;
            }
            .nav-links.open {
                transform: translateX(0);
            }
            .nav-links a {
                font-size: 20px;
            }
        }

        /* Sections Spacing */
        section {
            padding: 100px 0;
        }

        @media (max-width: 767px) {
            section {
                padding: 60px 0;
            }
        }

        /* Hero */
        #hero {
            min-height: 90vh;
            display: flex;
            align-items: center;
            background-color: var(--bg-white);
            padding-top: var(--header-height);
        }

        .hero-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 60px;
            align-items: center;
        }

        .hero-left h1 {
            font-size: 36px;
            font-weight: 700;
            line-height: 1.2;
            letter-spacing: -0.5px;
            color: var(--text-primary);
            margin-bottom: 16px;
        }

        .hero-left .subtitle {
            font-size: 20px;
            font-weight: 500;
            color: var(--primary);
            margin-bottom: 16px;
        }

        .hero-left p {
            font-size: 16px;
            color: var(--text-secondary);
            margin-bottom: 32px;
            max-width: 480px;
        }

        .hero-buttons {
            display: flex;
            gap: 16px;
            flex-wrap: wrap;
        }

        .btn-primary {
            background: var(--primary);
            color: #fff;
            border: none;
            padding: 14px 32px;
            border-radius: var(--radius-btn);
            font-weight: 600;
            font-size: 16px;
            letter-spacing: 0.5px;
            cursor: pointer;
            transition: background var(--transition), box-shadow var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }

        .btn-primary:hover {
            background: var(--primary-deep);
            box-shadow: var(--shadow-btn);
        }

        .btn-outline {
            background: transparent;
            color: var(--primary);
            border: 1.5px solid var(--primary);
            padding: 14px 32px;
            border-radius: var(--radius-btn);
            font-weight: 600;
            font-size: 16px;
            cursor: pointer;
            transition: background var(--transition), color var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }

        .btn-outline:hover {
            background: #eef4fc;
            color: var(--primary-deep);
        }

        .hero-right img {
            max-width: 520px;
            width: 100%;
            animation: float 6s ease-in-out infinite;
            border-radius: 24px;
        }

        @keyframes float {
            0% { transform: translateY(0); }
            50% { transform: translateY(-8px); }
            100% { transform: translateY(0); }
        }

        @media (max-width: 1023px) {
            .hero-grid {
                grid-template-columns: 1fr;
                text-align: center;
            }
            .hero-left p {
                max-width: 100%;
            }
            .hero-buttons {
                justify-content: center;
            }
            .hero-right img {
                margin: 0 auto;
                max-width: 400px;
            }
        }

        /* Metrics */
        .metrics-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 28px;
        }

        .metric-card {
            background: #fff;
            border-radius: var(--radius-card);
            padding: 32px 28px;
            box-shadow: var(--shadow-sm);
            transition: transform var(--transition), box-shadow var(--transition);
            text-align: center;
        }

        .metric-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .metric-number {
            font-family: var(--font-mono);
            font-size: 48px;
            font-weight: 700;
            background: linear-gradient(135deg, var(--accent), var(--accent-glow));
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
            display: inline-block;
            margin-bottom: 8px;
        }

        .metric-label {
            font-size: 18px;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: 6px;
        }

        .metric-desc {
            font-size: 14px;
            color: var(--text-secondary);
        }

        @media (max-width: 767px) {
            .metrics-grid {
                grid-template-columns: 1fr;
            }
        }

        /* Services */
        .section-title {
            text-align: center;
            margin-bottom: 50px;
        }

        .section-title h2 {
            font-size: 28px;
            font-weight: 600;
            color: var(--text-primary);
        }

        .services-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }

        .service-card {
            background: #fff;
            border: 1px solid var(--border-light);
            border-radius: var(--radius-card);
            padding: 28px;
            transition: border-color var(--transition), box-shadow var(--transition);
        }

        .service-card:hover {
            border-color: var(--primary);
            box-shadow: var(--shadow-hover);
        }

        .service-icon {
            width: 48px;
            height: 48px;
            background: #eef4fc;
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--primary);
            font-size: 24px;
            margin-bottom: 20px;
        }

        .service-card h4 {
            font-size: 18px;
            font-weight: 600;
            margin-bottom: 10px;
        }

        .service-card p {
            font-size: 14px;
            color: var(--text-secondary);
        }

        @media (max-width: 1023px) {
            .services-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        @media (max-width: 767px) {
            .services-grid {
                grid-template-columns: 1fr;
            }
        }

        /* Compare */
        #compare {
            background: var(--bg-light-gray);
        }

        .compare-wrapper {
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 20px;
            flex-wrap: wrap;
        }

        .compare-card {
            flex: 1;
            min-width: 280px;
            background: #fff;
            border-radius: var(--radius-card);
            padding: 36px 28px;
            box-shadow: var(--shadow-sm);
        }

        .compare-card.before {
            background: var(--bg-compare-left);
            color: #4a4a4a;
        }

        .compare-card.after {
            background: var(--bg-compare-right);
            border: 1px solid var(--primary);
        }

        .compare-card h3 {
            font-size: 22px;
            font-weight: 600;
            margin-bottom: 20px;
            color: inherit;
        }

        .compare-list {
            list-style: none;
        }

        .compare-list li {
            display: flex;
            align-items: center;
            gap: 10px;
            margin-bottom: 14px;
            font-size: 15px;
        }

        .compare-list i.fa-times {
            color: #b0a0a0;
            font-size: 18px;
        }

        .compare-list i.fa-check {
            color: var(--primary);
            font-size: 18px;
        }

        .vs-badge {
            width: 60px;
            height: 60px;
            background: #fff;
            border: 2px solid var(--primary);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 20px;
            color: var(--primary);
            flex-shrink: 0;
        }

        @media (max-width: 767px) {
            .compare-wrapper {
                flex-direction: column;
            }
            .vs-badge {
                margin: 10px 0;
            }
        }

        /* FAQ */
        #faq {
            background: var(--bg-white);
        }

        .faq-list {
            max-width: 800px;
            margin: 0 auto;
            display: flex;
            flex-direction: column;
            gap: 12px;
        }

        .faq-item {
            background: #fff;
            border-bottom: 1px solid var(--border-light);
            border-radius: var(--radius-faq);
            overflow: hidden;
        }

        .faq-question {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 20px 24px;
            cursor: pointer;
            font-weight: 600;
            font-size: 16px;
            background: #fff;
            transition: background var(--transition);
        }

        .faq-question:hover {
            background: #fafbfc;
        }

        .faq-toggle {
            font-size: 20px;
            transition: transform var(--transition);
            color: var(--primary);
        }

        .faq-item.active .faq-toggle {
            transform: rotate(45deg);
        }

        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease, padding 0.3s ease;
            padding: 0 24px;
            color: var(--text-secondary);
            font-size: 15px;
        }

        .faq-item.active .faq-answer {
            max-height: 200px;
            padding: 0 24px 20px;
        }

        /* CTA Form */
        #contact {
            background: var(--bg-white);
        }

        .contact-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 60px;
            align-items: center;
        }

        .contact-left h2 {
            font-size: 28px;
            font-weight: 600;
            margin-bottom: 16px;
        }

        .contact-left p {
            color: var(--text-secondary);
            font-size: 16px;
        }

        .contact-form {
            background: #fff;
            padding: 32px 28px;
            border-radius: var(--radius-card);
            box-shadow: var(--shadow-sm);
        }

        .form-group {
            margin-bottom: 16px;
        }

        .form-group input {
            width: 100%;
            height: 48px;
            border: 1px solid var(--border-input);
            border-radius: var(--radius-btn);
            padding: 0 16px;
            font-size: 16px;
            transition: border-color var(--transition);
            background: #fff;
        }

        .form-group input:focus {
            outline: none;
            border-color: var(--primary);
        }

        .btn-submit {
            width: 100%;
            background: var(--primary);
            color: #fff;
            border: none;
            padding: 14px;
            border-radius: var(--radius-btn);
            font-weight: 600;
            font-size: 16px;
            cursor: pointer;
            transition: background var(--transition), transform var(--transition);
            margin-top: 8px;
        }

        .btn-submit:hover {
            background: var(--primary-deep);
            transform: translateY(-2px);
        }

        @media (max-width: 767px) {
            .contact-grid {
                grid-template-columns: 1fr;
                gap: 30px;
            }
        }

        /* Footer */
        #footer {
            background: #1a2332;
            color: var(--text-muted);
            padding: 60px 0 30px;
            font-size: 15px;
        }

        .footer-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 40px;
        }

        .footer-logo {
            font-size: 22px;
            font-weight: 700;
            color: #fff;
            margin-bottom: 12px;
        }

        .footer-links {
            display: flex;
            flex-direction: column;
            gap: 8px;
        }

        .footer-links a {
            color: var(--text-muted);
            transition: color var(--transition);
        }

        .footer-links a:hover {
            color: #fff;
        }

        .copyright {
            margin-top: 40px;
            text-align: center;
            font-size: 14px;
            color: #6a737d;
        }

        @media (max-width: 767px) {
            .footer-grid {
                grid-template-columns: 1fr;
                text-align: center;
            }
        }