/* roulang page: index */
:root {
            --color-bg-deepest: #08080C;
            --color-bg-primary: #0E0E14;
            --color-bg-card: #16161E;
            --color-bg-card-alt: #1C1C26;
            --color-bg-surface: #22222D;
            --color-brand-orange: #FF5F1F;
            --color-brand-purple: #9B1B6A;
            --color-brand-mid: #D42E6A;
            --color-brand-gradient: linear-gradient(135deg, #FF5F1F 0%, #D42E6A 45%, #9B1B6A 100%);
            --color-brand-gradient-subtle: linear-gradient(135deg, rgba(255, 95, 31, 0.12) 0%, rgba(155, 27, 106, 0.12) 100%);
            --color-accent-cyan: #00D4FF;
            --color-accent-green: #00E676;
            --color-accent-amber: #FFAB00;
            --color-text-primary: #EDEDF5;
            --color-text-secondary: #A0A0B5;
            --color-text-tertiary: #6A6A7A;
            --color-text-inverse: #0E0E14;
            --color-border-subtle: rgba(255, 255, 255, 0.06);
            --color-border-card: rgba(255, 255, 255, 0.10);
            --color-border-accent: rgba(255, 95, 31, 0.40);
            --shadow-card: 0 2px 16px rgba(0, 0, 0, 0.40), 0 0 1px rgba(255, 255, 255, 0.06);
            --shadow-card-hover: 0 8px 32px rgba(0, 0, 0, 0.55), 0 0 0 1px rgba(255, 95, 31, 0.25);
            --shadow-button: 0 4px 14px rgba(255, 95, 31, 0.35);
            --shadow-badge: 0 0 20px rgba(0, 212, 255, 0.25);
            --radius-sm: 8px;
            --radius-md: 16px;
            --radius-lg: 24px;
            --radius-xl: 32px;
            --radius-full: 9999px;
            --font-title: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
            --font-body: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
            --font-mono: "JetBrains Mono", "SF Mono", "Cascadia Code", "Consolas", monospace;
        }

        *,
        *::before,
        *::after {
            box-sizing: border-box;
        }

        html {
            scroll-behavior: smooth;
            scroll-padding-top: 80px;
        }

        body {
            margin: 0;
            padding: 0;
            font-family: var(--font-body);
            font-size: 16px;
            line-height: 1.75;
            color: var(--color-text-primary);
            background-color: var(--color-bg-primary);
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            overflow-x: hidden;
        }

        a {
            text-decoration: none;
            color: inherit;
            transition: color 0.25s ease, background-color 0.25s ease, border-color 0.25s ease, opacity 0.25s ease;
        }

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

        button,
        input,
        select,
        textarea {
            font-family: inherit;
            font-size: inherit;
            outline: none;
            transition: border-color 0.25s ease, box-shadow 0.25s ease, background-color 0.25s ease;
        }

        button {
            cursor: pointer;
            border: none;
        }

        ::selection {
            background: rgba(255, 95, 31, 0.35);
            color: #fff;
        }

        .brand-gradient-text {
            background: var(--color-brand-gradient);
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
            color: transparent;
        }

        .brand-gradient-bg {
            background: var(--color-brand-gradient);
        }

        .brand-gradient-border {
            position: relative;
        }
        .brand-gradient-border::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 100%;
            height: 1px;
            background: linear-gradient(90deg, #FF5F1F 0%, rgba(255, 95, 31, 0.4) 50%, transparent 100%);
        }

        .card-glow {
            box-shadow: var(--shadow-card);
            transition: box-shadow 0.35s ease, transform 0.35s ease, border-color 0.35s ease;
            border: 1px solid transparent;
        }
        .card-glow:hover {
            box-shadow: var(--shadow-card-hover);
            transform: translateY(-4px);
            border-color: var(--color-border-accent);
        }

        .badge-glow {
            box-shadow: var(--shadow-badge);
        }

        .btn-primary {
            background: var(--color-brand-gradient);
            color: #fff;
            font-weight: 700;
            border-radius: var(--radius-full);
            padding: 14px 32px;
            box-shadow: var(--shadow-button);
            transition: all 0.3s ease;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            white-space: nowrap;
        }
        .btn-primary:hover {
            transform: scale(1.04);
            box-shadow: 0 6px 22px rgba(255, 95, 31, 0.5);
            filter: brightness(1.08);
        }

        .btn-outline {
            background: transparent;
            color: var(--color-text-primary);
            font-weight: 600;
            border-radius: var(--radius-full);
            padding: 14px 32px;
            border: 1.5px solid var(--color-text-secondary);
            transition: all 0.3s ease;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            white-space: nowrap;
        }
        .btn-outline:hover {
            border-color: var(--color-brand-orange);
            color: var(--color-brand-orange);
            background: rgba(255, 95, 31, 0.06);
        }

        .nav-pill {
            display: inline-flex;
            align-items: center;
            padding: 10px 20px;
            border-radius: var(--radius-full);
            font-weight: 600;
            font-size: 0.9rem;
            color: var(--color-text-primary);
            background: transparent;
            border: 1.5px solid transparent;
            transition: all 0.3s ease;
            white-space: nowrap;
        }
        .nav-pill:hover {
            background: rgba(255, 95, 31, 0.1);
            border-color: rgba(255, 95, 31, 0.35);
            color: #fff;
        }
        .nav-pill.active {
            background: var(--color-brand-gradient);
            color: #fff;
            border-color: transparent;
            font-weight: 700;
        }

        .input-field {
            background: var(--color-bg-surface);
            border: 1px solid var(--color-border-subtle);
            border-radius: var(--radius-md);
            padding: 14px 18px;
            color: #fff;
            width: 100%;
            font-size: 1rem;
        }
        .input-field::placeholder {
            color: var(--color-text-tertiary);
        }
        .input-field:focus {
            border-color: var(--color-brand-orange);
            box-shadow: 0 0 0 3px rgba(255, 95, 31, 0.15);
        }

        .section-spacing {
            padding: 140px 0;
        }
        @media (max-width: 768px) {
            .section-spacing {
                padding: 80px 0;
            }
            .nav-pill {
                padding: 12px 20px;
                font-size: 1rem;
                border-radius: var(--radius-md);
                width: 100%;
                justify-content: center;
            }
        }
        @media (max-width: 480px) {
            .section-spacing {
                padding: 60px 0;
            }
        }

        .metric-number {
            font-family: var(--font-mono);
            font-variant-numeric: tabular-nums;
            font-feature-settings: "tnum";
            font-weight: 800;
            font-size: 3.2rem;
            line-height: 1;
            letter-spacing: -0.02em;
        }
        @media (max-width: 768px) {
            .metric-number {
                font-size: 2.5rem;
            }
        }

        .trend-bar {
            height: 4px;
            border-radius: 4px;
            background: var(--color-accent-cyan);
            transition: width 0.8s ease;
        }
        .trend-bar.green {
            background: var(--color-accent-green);
        }

        .faq-item {
            border-radius: var(--radius-md);
            overflow: hidden;
            transition: all 0.3s ease;
        }
        .faq-question {
            cursor: pointer;
            background: var(--color-bg-card);
            padding: 20px 24px;
            font-weight: 600;
            font-size: 1.125rem;
            display: flex;
            align-items: center;
            gap: 14px;
            transition: background 0.3s ease;
            user-select: none;
        }
        .faq-question:hover {
            background: var(--color-bg-card-alt);
        }
        .faq-question .faq-icon {
            flex-shrink: 0;
            width: 28px;
            height: 28px;
            border-radius: 50%;
            background: rgba(255, 95, 31, 0.15);
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--color-brand-orange);
            font-size: 0.85rem;
            transition: all 0.35s ease;
        }
        .faq-item.open .faq-question .faq-icon {
            transform: rotate(45deg);
            background: var(--color-brand-gradient);
            color: #fff;
        }
        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.4s ease, padding 0.4s ease;
            background: var(--color-bg-card-alt);
            color: var(--color-text-secondary);
            line-height: 1.7;
        }
        .faq-item.open .faq-answer {
            max-height: 400px;
            padding: 20px 24px;
            border-top: 1px solid var(--color-border-subtle);
        }

        #mobile-menu {
            display: none;
        }
        @media (max-width: 767px) {
            #mobile-menu.open {
                display: flex;
                flex-direction: column;
                position: fixed;
                top: 0;
                left: 0;
                width: 100%;
                height: 100vh;
                background: rgba(8, 8, 12, 0.96);
                backdrop-filter: blur(16px);
                z-index: 999;
                padding: 100px 24px 40px;
                gap: 10px;
                align-items: stretch;
            }
        }