/* roulang page: index */
:root {
            --brand-primary: #0F766E;
            --brand-cyan: #06B6D4;
            --brand-cyan-light: #E0F2FE;
            --brand-purple: #7C3AED;
            --brand-amber: #F59E0B;
            --dark-deep: #0B0F19;
            --dark-card: #131A2A;
            --bg-light: #F8FAFC;
            --text-heading: #0F172A;
            --text-body: #334155;
            --text-muted: #64748B;
            --border-light: rgba(226, 232, 240, 0.8);
            --border-dark: rgba(255, 255, 255, 0.08);
            --radius-md: 12px;
            --radius-lg: 16px;
            --shadow-sm: 0 4px 20px -2px rgba(15, 23, 42, 0.05);
            --shadow-hover: 0 16px 36px -6px rgba(15, 118, 110, 0.16);
            --transition-smooth: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
        }

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
            background-color: var(--bg-light);
            color: var(--text-body);
            line-height: 1.65;
            overflow-x: hidden;
        }

        /* Top Bar Doc Header */
        .top-meta-bar {
            background-color: #042F2E;
            color: #99F6E4;
            font-size: 0.8rem;
            padding: 6px 0;
            border-bottom: 1px solid rgba(20, 184, 166, 0.2);
        }

        .navbar-custom {
            background: rgba(255, 255, 255, 0.96);
            backdrop-filter: blur(12px);
            border-bottom: 1px solid rgba(226, 232, 240, 0.8);
            padding: 0.85rem 0;
            transition: var(--transition-smooth);
        }

        .navbar-brand {
            font-weight: 800;
            font-size: 1.35rem;
            color: var(--brand-primary) !important;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .navbar-brand i {
            color: var(--brand-cyan);
            font-size: 1.45rem;
        }

        .nav-link {
            font-weight: 600;
            color: var(--text-heading) !important;
            font-size: 0.95rem;
            padding: 0.5rem 0.9rem !important;
            transition: var(--transition-smooth);
            border-radius: 6px;
        }

        .nav-link:hover, .nav-link.active {
            color: var(--brand-primary) !important;
            background-color: rgba(15, 118, 110, 0.06);
        }

        .nav-doc-search {
            background-color: #F1F5F9;
            border: 1px solid #E2E8F0;
            border-radius: 8px;
            padding: 5px 12px;
            font-size: 0.85rem;
            color: var(--text-muted);
            display: flex;
            align-items: center;
            gap: 8px;
            cursor: pointer;
        }

        /* Hero Video Mock Section */
        .hero-video-wrap {
            position: relative;
            background: linear-gradient(135deg, #022c22 0%, #064e3b 50%, #042f2e 100%);
            color: #ffffff;
            padding: 6rem 0 5rem;
            overflow: hidden;
        }

        .hero-bg-overlay {
            position: absolute;
            inset: 0;
            background-image: url('/assets/images/7b52b2742ec41f14.jpg');
            background-size: cover;
            background-position: center;
            opacity: 0.16;
            mix-blend-mode: overlay;
        }

        .hero-badge {
            background-color: rgba(6, 182, 212, 0.15);
            color: #67E8F9;
            border: 1px solid rgba(6, 182, 212, 0.35);
            padding: 6px 14px;
            border-radius: 50px;
            font-size: 0.85rem;
            font-weight: 600;
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }

        .hero-title {
            font-size: 2.75rem;
            font-weight: 800;
            line-height: 1.25;
            letter-spacing: -0.02em;
            margin: 1.25rem 0;
        }

        .hero-desc {
            font-size: 1.05rem;
            color: #CCFBF1;
            line-height: 1.8;
            max-width: 620px;
            margin-bottom: 2rem;
        }

        /* Mock Video Window Frame */
        .video-stage-frame {
            position: relative;
            background: #0F172A;
            border-radius: var(--radius-lg);
            border: 1px solid rgba(255, 255, 255, 0.15);
            box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
            overflow: hidden;
        }

        .video-stage-topbar {
            background: #1E293B;
            padding: 10px 16px;
            display: flex;
            align-items: center;
            gap: 8px;
            border-bottom: 1px solid rgba(255, 255, 255, 0.05);
        }

        .window-dot {
            width: 10px;
            height: 10px;
            border-radius: 50%;
        }

        .window-dot-red { background: #EF4444; }
        .window-dot-yellow { background: #F59E0B; }
        .window-dot-green { background: #10B981; }

        .video-stage-content {
            position: relative;
            min-height: 330px;
            background: url('/assets/images/ea759bcbae5f84b8.jpg') center/cover no-repeat;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .video-play-btn {
            width: 68px;
            height: 68px;
            background: rgba(6, 182, 212, 0.9);
            color: #ffffff;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            cursor: pointer;
            box-shadow: 0 0 0 10px rgba(6, 182, 212, 0.35);
            transition: var(--transition-smooth);
        }

        .video-play-btn:hover {
            transform: scale(1.08);
            background: #06B6D4;
            box-shadow: 0 0 0 16px rgba(6, 182, 212, 0.45);
        }

        .video-data-overlay {
            position: absolute;
            bottom: 14px;
            left: 14px;
            right: 14px;
            background: rgba(11, 15, 25, 0.85);
            backdrop-filter: blur(8px);
            border-radius: 8px;
            padding: 10px 16px;
            display: flex;
            justify-content: space-between;
            font-size: 0.8rem;
            color: #94A3B8;
        }

        /* Buttons */
        .btn-brand-primary {
            background-color: var(--brand-cyan);
            color: #042F2E;
            font-weight: 700;
            padding: 12px 28px;
            border-radius: 8px;
            border: none;
            transition: var(--transition-smooth);
            display: inline-flex;
            align-items: center;
            gap: 8px;
        }

        .btn-brand-primary:hover {
            background-color: #22D3EE;
            color: #042F2E;
            transform: translateY(-2px);
            box-shadow: 0 8px 20px rgba(6, 182, 212, 0.4);
        }

        .btn-brand-outline {
            background: transparent;
            color: #ffffff;
            border: 1px solid rgba(255, 255, 255, 0.35);
            font-weight: 600;
            padding: 12px 24px;
            border-radius: 8px;
            transition: var(--transition-smooth);
        }

        .btn-brand-outline:hover {
            background: rgba(255, 255, 255, 0.1);
            color: #ffffff;
            border-color: #ffffff;
        }

        /* Section Global Typography */
        .section-padding {
            padding: 5rem 0;
        }

        .section-header {
            max-width: 720px;
            margin: 0 auto 3.5rem;
            text-align: center;
        }

        .section-eyebrow {
            color: var(--brand-primary);
            font-weight: 700;
            font-size: 0.88rem;
            text-transform: uppercase;
            letter-spacing: 0.05em;
            margin-bottom: 0.5rem;
            display: block;
        }

        .section-title {
            font-size: 2.15rem;
            font-weight: 800;
            color: var(--text-heading);
            letter-spacing: -0.01em;
            margin-bottom: 1rem;
        }

        .section-subtitle {
            font-size: 1rem;
            color: var(--text-muted);
            line-height: 1.75;
        }

        /* Custom Cards */
        .data-card {
            background: #ffffff;
            border-radius: var(--radius-md);
            border: 1px solid var(--border-light);
            box-shadow: var(--shadow-sm);
            padding: 2rem;
            height: 100%;
            transition: var(--transition-smooth);
            position: relative;
        }

        .data-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
            border-color: rgba(15, 118, 110, 0.3);
        }

        .card-icon-box {
            width: 52px;
            height: 52px;
            border-radius: 10px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.4rem;
            margin-bottom: 1.25rem;
        }

        .icon-teal { background: #CCFBF1; color: var(--brand-primary); }
        .icon-cyan { background: #CFFAFE; color: #0891B2; }
        .icon-purple { background: #EDE9FE; color: var(--brand-purple); }
        .icon-amber { background: #FEF3C7; color: #D97706; }

        .card-item-title {
            font-size: 1.25rem;
            font-weight: 700;
            color: var(--text-heading);
            margin-bottom: 0.75rem;
        }

        .card-item-desc {
            font-size: 0.92rem;
            color: var(--text-muted);
            line-height: 1.65;
            margin-bottom: 0;
        }

        /* Dark Deep Analytics Section */
        .dark-model-section {
            background: var(--dark-deep);
            color: #F8FAFC;
            position: relative;
        }

        .dark-model-card {
            background: var(--dark-card);
            border: 1px solid var(--border-dark);
            border-radius: var(--radius-md);
            padding: 2rem;
            height: 100%;
        }

        .metric-bar-group {
            margin-top: 1.5rem;
        }

        .metric-bar-label {
            display: flex;
            justify-content: space-between;
            font-size: 0.85rem;
            margin-bottom: 6px;
            color: #94A3B8;
        }

        .metric-bar-track {
            height: 8px;
            background: rgba(255, 255, 255, 0.08);
            border-radius: 4px;
            overflow: hidden;
            margin-bottom: 1.25rem;
        }

        .metric-bar-fill {
            height: 100%;
            border-radius: 4px;
        }

        /* Metric Highlights Strip */
        .metrics-strip {
            background: #ffffff;
            border-top: 1px solid #E2E8F0;
            border-bottom: 1px solid #E2E8F0;
            padding: 3rem 0;
        }

        .metric-num {
            font-size: 2.75rem;
            font-weight: 800;
            color: var(--brand-primary);
            line-height: 1;
            margin-bottom: 0.5rem;
        }

        .metric-tag {
            font-size: 0.95rem;
            font-weight: 600;
            color: var(--text-heading);
            margin-bottom: 0.25rem;
        }

        .metric-sub {
            font-size: 0.8rem;
            color: var(--text-muted);
        }

        /* Accordion FAQ Custom */
        .accordion-item {
            border: 1px solid var(--border-light);
            border-radius: 12px !important;
            margin-bottom: 1rem;
            overflow: hidden;
            box-shadow: var(--shadow-sm);
        }

        .accordion-button {
            font-weight: 700;
            color: var(--text-heading);
            padding: 1.25rem 1.5rem;
            background-color: #ffffff;
        }

        .accordion-button:not(.collapsed) {
            color: var(--brand-primary);
            background-color: #F0FDFA;
            box-shadow: none;
        }

        .accordion-button:focus {
            box-shadow: none;
            border-color: var(--brand-primary);
        }

        .accordion-body {
            padding: 1.25rem 1.5rem;
            font-size: 0.95rem;
            color: var(--text-body);
            line-height: 1.8;
            background-color: #ffffff;
        }

        /* Form Controls */
        .form-control-custom {
            height: 50px;
            border-radius: 8px;
            border: 1px solid #CBD5E1;
            padding: 0 16px;
            font-size: 0.95rem;
            background: #F8FAFC;
        }

        .form-control-custom:focus {
            background: #ffffff;
            border-color: var(--brand-primary);
            box-shadow: 0 0 0 3px rgba(15, 118, 110, 0.15);
        }

        /* Footer */
        .site-footer {
            background: #022C22;
            color: #94A3B8;
            padding: 4.5rem 0 2rem;
            border-top: 1px solid rgba(255, 255, 255, 0.08);
            font-size: 0.9rem;
        }

        .site-footer h6 {
            color: #F8FAFC;
            font-weight: 700;
            margin-bottom: 1.25rem;
            font-size: 1rem;
        }

        .site-footer a {
            color: #94A3B8;
            text-decoration: none;
            transition: var(--transition-smooth);
        }

        .site-footer a:hover {
            color: var(--brand-cyan);
        }

        .footer-divider {
            border-top: 1px solid rgba(255, 255, 255, 0.08);
            margin: 3rem 0 2rem;
        }

        @media (max-width: 991px) {
            .hero-title { font-size: 2.15rem; }
            .section-title { font-size: 1.85rem; }
            .section-padding { padding: 3.5rem 0; }
        }