/* roulang page: index */
:root {
            --color-black: #0B0D10;
            --color-cyan: #00E5A1;
            --color-cyan-dark: #00B87A;
            --color-silver: #E8ECF0;
            --color-graphite: #2A2E35;
            --color-text: #0B0D10;
            --color-text-secondary: #5C626A;
            --color-text-white: #FFFFFF;
            --color-text-muted: #9BA3AE;
            --color-green: #00C48C;
            --color-red: #FF4D4F;
            --font-stack: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
            --container-max: 1280px;
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 16px;
            --radius-pill: 20px;
            --shadow-card: 0 2px 12px rgba(0, 0, 0, 0.04), 0 0 0 1px rgba(0, 0, 0, 0.03);
            --shadow-card-hover: 0 8px 24px rgba(0, 0, 0, 0.08), 0 0 0 1px rgba(0, 0, 0, 0.04);
            --shadow-glow: 0 0 32px rgba(0, 229, 161, 0.20);
            --transition-fast: 0.2s ease;
            --transition-smooth: 0.25s ease;
            --transition-slow: 0.35s ease;
            --nav-height: 72px;
        }

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

        html {
            scroll-behavior: smooth;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

        body {
            font-family: var(--font-stack);
            font-size: 16px;
            line-height: 1.75;
            font-weight: 400;
            color: var(--color-text);
            background-color: #FFFFFF;
            overflow-x: hidden;
        }

        a {
            color: inherit;
            text-decoration: none;
        }
        img {
            display: block;
            max-width: 100%;
            height: auto;
        }
        button {
            font-family: inherit;
            cursor: pointer;
            border: none;
            background: none;
            font-size: inherit;
        }
        input {
            font-family: inherit;
            font-size: inherit;
        }
        ul,
        ol {
            list-style: none;
        }
        h1,
        h2,
        h3,
        h4 {
            font-weight: 700;
            color: var(--color-text);
        }

        .container {
            max-width: var(--container-max);
            margin: 0 auto;
            padding: 0 24px;
        }
        @media(max-width:767px) {
            .container {
                padding: 0 16px;
            }
        }

        .section-padding {
            padding: 120px 0;
        }
        @media(max-width:1023px) {
            .section-padding {
                padding: 80px 0;
            }
        }
        @media(max-width:767px) {
            .section-padding {
                padding: 60px 0;
            }
        }

        .section-title-group {
            text-align: center;
            margin-bottom: 56px;
        }
        .section-title-group.left-align {
            text-align: left;
        }
        .section-title-group .decorator-line {
            display: block;
            width: 40px;
            height: 2px;
            background: var(--color-cyan);
            margin: 0 auto 16px;
            border-radius: 1px;
        }
        .section-title-group.left-align .decorator-line {
            margin: 0 0 16px;
        }
        .section-title-group h3 {
            font-size: 28px;
            line-height: 1.4;
            font-weight: 600;
            letter-spacing: -0.005em;
        }
        .section-title-group p.subtitle {
            font-size: 16px;
            color: var(--color-text-secondary);
            margin-top: 8px;
            max-width: 520px;
            margin-left: auto;
            margin-right: auto;
        }
        .section-title-group.left-align p.subtitle {
            margin-left: 0;
            margin-right: 0;
        }
        @media(max-width:767px) {
            .section-title-group h3 {
                font-size: 22px;
            }
            .section-title-group {
                margin-bottom: 36px;
            }
        }

        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            font-weight: 600;
            font-size: 15px;
            padding: 14px 32px;
            border-radius: var(--radius-sm);
            transition: transform var(--transition-fast), box-shadow var(--transition-fast), background var(--transition-fast), filter var(--transition-fast);
            letter-spacing: 0.01em;
            white-space: nowrap;
        }
        .btn-primary {
            background: linear-gradient(135deg, var(--color-cyan) 0%, var(--color-cyan-dark) 100%);
            color: #FFFFFF;
            box-shadow: 0 4px 16px rgba(0, 229, 161, 0.25);
        }
        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 28px rgba(0, 229, 161, 0.35);
            filter: brightness(1.08);
        }
        .btn-primary:active {
            transform: translateY(0);
            box-shadow: 0 2px 8px rgba(0, 229, 161, 0.20);
        }
        .btn-outline {
            background: transparent;
            color: var(--color-cyan);
            border: 1.5px solid var(--color-cyan);
        }
        .btn-outline:hover {
            background: rgba(0, 229, 161, 0.08);
            transform: translateY(-2px);
        }
        .btn-outline:active {
            transform: translateY(0);
        }
        .btn-sm {
            padding: 10px 22px;
            font-size: 14px;
        }

        .text-link {
            color: var(--color-cyan);
            font-weight: 500;
            background: linear-gradient(var(--color-cyan), var(--color-cyan)) 0 100% / 0% 2px no-repeat;
            transition: background-size var(--transition-smooth);
            padding-bottom: 2px;
        }
        .text-link:hover {
            background-size: 100% 2px;
        }

        .tag {
            display: inline-block;
            font-size: 12px;
            font-weight: 500;
            padding: 4px 14px;
            border-radius: var(--radius-pill);
            border: 1px solid var(--color-cyan);
            color: var(--color-cyan);
            background: rgba(0, 229, 161, 0.05);
            letter-spacing: 0.02em;
        }

        /* Header / Nav */
        #header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 1000;
            height: var(--nav-height);
            display: flex;
            align-items: center;
            background: rgba(255, 255, 255, 0.92);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            transition: background var(--transition-smooth), box-shadow var(--transition-smooth);
            border-bottom: 1px solid transparent;
        }
        #header.scrolled {
            background: rgba(255, 255, 255, 0.85);
            box-shadow: 0 1px 20px rgba(0, 0, 0, 0.06);
            border-bottom: 1px solid rgba(0, 0, 0, 0.06);
        }
        #header .nav-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            width: 100%;
            max-width: var(--container-max);
            margin: 0 auto;
            padding: 0 24px;
        }
        #header .logo {
            display: flex;
            align-items: center;
            gap: 10px;
            font-weight: 700;
            font-size: 20px;
            color: var(--color-black);
            letter-spacing: -0.01em;
            flex-shrink: 0;
        }
        #header .logo svg {
            width: 34px;
            height: 34px;
            flex-shrink: 0;
        }
        #header .nav-links {
            display: flex;
            align-items: center;
            gap: 28px;
        }
        #header .nav-links a {
            font-size: 15px;
            font-weight: 500;
            color: var(--color-text-secondary);
            transition: color var(--transition-fast);
            position: relative;
            padding: 4px 0;
        }
        #header .nav-links a:hover,
        #header .nav-links a.active {
            color: var(--color-cyan);
        }
        #header .nav-links a::after {
            content: '';
            position: absolute;
            bottom: -2px;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--color-cyan);
            border-radius: 1px;
            transition: width var(--transition-fast);
        }
        #header .nav-links a.active::after {
            width: 100%;
        }
        #header .hamburger {
            display: none;
            flex-direction: column;
            gap: 5px;
            cursor: pointer;
            z-index: 1001;
            padding: 8px;
        }
        #header .hamburger span {
            display: block;
            width: 26px;
            height: 2px;
            background: var(--color-black);
            border-radius: 1px;
            transition: transform var(--transition-fast), opacity var(--transition-fast);
        }
        #header .hamburger.open span:nth-child(1) {
            transform: translateY(7px) rotate(45deg);
        }
        #header .hamburger.open span:nth-child(2) {
            opacity: 0;
        }
        #header .hamburger.open span:nth-child(3) {
            transform: translateY(-7px) rotate(-45deg);
        }
        #mobile-menu {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100vh;
            background: var(--color-black);
            z-index: 999;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            gap: 32px;
            opacity: 0;
            pointer-events: none;
            transition: opacity var(--transition-smooth);
        }
        #mobile-menu.open {
            display: flex;
            opacity: 1;
            pointer-events: all;
        }
        #mobile-menu a {
            color: #FFFFFF;
            font-size: 22px;
            font-weight: 600;
            transition: color var(--transition-fast);
        }
        #mobile-menu a:hover {
            color: var(--color-cyan);
        }
        #mobile-menu .btn-primary {
            margin-top: 16px;
        }
        @media(max-width:767px) {
            #header .nav-links {
                display: none;
            }
            #header .hamburger {
                display: flex;
            }
            #header .nav-inner {
                padding: 0 16px;
            }
        }

        /* Hero */
        #hero {
            min-height: 100vh;
            display: flex;
            align-items: center;
            padding-top: var(--nav-height);
            background: #FAFBFC;
            position: relative;
            overflow: hidden;
        }
        #hero .hero-grid {
            display: grid;
            grid-template-columns: 5fr 7fr;
            gap: 48px;
            align-items: center;
            width: 100%;
        }
        #hero .hero-left h1 {
            font-size: 56px;
            line-height: 1.2;
            font-weight: 700;
            letter-spacing: -0.02em;
            color: var(--color-black);
            margin-bottom: 16px;
        }
        #hero .hero-left h2 {
            font-size: 22px;
            line-height: 1.5;
            font-weight: 400;
            color: var(--color-text-secondary);
            letter-spacing: 0;
            margin-bottom: 8px;
        }
        #hero .hero-left .hero-desc {
            font-size: 15px;
            color: var(--color-text-muted);
            margin-bottom: 28px;
            max-width: 380px;
        }
        #hero .hero-left .btn-group {
            display: flex;
            gap: 14px;
            flex-wrap: wrap;
        }
        #hero .hero-right {
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 420px;
        }
        #hero .hero-card-wrapper {
            position: relative;
            width: 100%;
            max-width: 540px;
            background: #FFFFFF;
            border-radius: var(--radius-lg);
            padding: 8px;
            transform: rotate(3deg);
            box-shadow: var(--shadow-card-hover);
            z-index: 2;
        }
        #hero .hero-card-wrapper img {
            border-radius: var(--radius-md);
            width: 100%;
            height: auto;
            object-fit: cover;
            aspect-ratio: 16/10;
        }
        #hero .hero-card-outline {
            position: absolute;
            top: -12px;
            left: -12px;
            right: 12px;
            bottom: 12px;
            border: 1.5px solid rgba(0, 229, 161, 0.4);
            border-radius: var(--radius-lg);
            z-index: 1;
            pointer-events: none;
        }
        #hero .hero-bg-dots {
            position: absolute;
            width: 300px;
            height: 300px;
            background: radial-gradient(circle, rgba(0, 229, 161, 0.10) 1px, transparent 1px);
            background-size: 20px 20px;
            border-radius: 50%;
            z-index: 0;
            animation: heroFloat 8s ease-in-out infinite;
            right: -40px;
            bottom: -60px;
        }
        @keyframes heroFloat {
            0%,
            100% {
                transform: translate(0, 0);
            }
            25% {
                transform: translate(6px, -8px);
            }
            50% {
                transform: translate(-4px, 4px);
            }
            75% {
                transform: translate(8px, 6px);
            }
        }
        @media(max-width:1023px) {
            #hero .hero-grid {
                grid-template-columns: 1fr 1fr;
                gap: 32px;
            }
            #hero .hero-left h1 {
                font-size: 40px;
            }
            #hero .hero-left h2 {
                font-size: 18px;
            }
            #hero .hero-right {
                min-height: 320px;
            }
        }
        @media(max-width:767px) {
            #hero .hero-grid {
                grid-template-columns: 1fr;
                text-align: center;
            }
            #hero .hero-left {
                order: 1;
            }
            #hero .hero-right {
                order: 0;
                min-height: 260px;
            }
            #hero .hero-left h1 {
                font-size: 36px;
            }
            #hero .hero-left h2 {
                font-size: 17px;
            }
            #hero .hero-left .hero-desc {
                max-width: 100%;
            }
            #hero .hero-left .btn-group {
                justify-content: center;
            }
            #hero .hero-card-wrapper {
                max-width: 90%;
                margin: 0 auto;
                transform: rotate(1.5deg);
            }
            #hero .hero-bg-dots {
                width: 180px;
                height: 180px;
                right: -20px;
                bottom: -30px;
            }
        }

        /* Highlights */
        #highlights {
            background: var(--color-silver);
        }
        #highlights .highlights-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }
        #highlights .highlight-card {
            background: #FFFFFF;
            border-radius: var(--radius-md);
            padding: 40px 28px;
            text-align: center;
            box-shadow: var(--shadow-card);
            transition: transform var(--transition-smooth), box-shadow var(--transition-smooth);
        }
        #highlights .highlight-card:hover {
            transform: translateY(-6px);
            box-shadow: var(--shadow-card-hover);
        }
        #highlights .highlight-card .data-number {
            font-size: 64px;
            line-height: 1;
            font-weight: 700;
            color: var(--color-cyan);
            font-variant-numeric: tabular-nums;
            letter-spacing: -0.03em;
            margin-bottom: 12px;
        }
        #highlights .highlight-card h4 {
            font-size: 20px;
            line-height: 1.5;
            font-weight: 600;
            margin-bottom: 6px;
        }
        #highlights .highlight-card p {
            font-size: 14px;
            color: var(--color-text-secondary);
        }
        @media(max-width:1023px) {
            #highlights .highlights-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            #highlights .highlights-grid .highlight-card:nth-child(3) {
                grid-column: 1 / -1;
                max-width: 400px;
                justify-self: center;
            }
        }
        @media(max-width:767px) {
            #highlights .highlights-grid {
                grid-template-columns: 1fr;
            }
            #highlights .highlights-grid .highlight-card:nth-child(3) {
                grid-column: auto;
                max-width: 100%;
            }
            #highlights .highlight-card .data-number {
                font-size: 48px;
            }
        }

        /* Cases */
        #cases .cases-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 28px;
        }
        #cases .case-card {
            background: #FFFFFF;
            border-radius: var(--radius-lg);
            overflow: hidden;
            box-shadow: var(--shadow-card);
            transition: transform var(--transition-smooth), box-shadow var(--transition-smooth);
            opacity: 0;
            transform: translateY(20px);
        }
        #cases .case-card.visible {
            opacity: 1;
            transform: translateY(0);
            transition: opacity 0.6s ease, transform 0.6s ease, box-shadow var(--transition-smooth);
        }
        #cases .case-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-card-hover);
        }
        #cases .case-card:nth-child(odd) {
            margin-top: 0;
        }
        #cases .case-card:nth-child(even) {
            margin-top: 48px;
        }
        #cases .case-card img {
            width: 100%;
            height: 240px;
            object-fit: cover;
            border-radius: var(--radius-md) var(--radius-md) 0 0;
        }
        #cases .case-card .case-body {
            padding: 22px 20px 20px;
        }
        #cases .case-card .case-body h4 {
            font-size: 20px;
            font-weight: 600;
            margin-bottom: 8px;
        }
        #cases .case-card .case-body .tag-row {
            margin-bottom: 8px;
            display: flex;
            flex-wrap: wrap;
            gap: 6px;
        }
        #cases .case-card .case-body .case-desc {
            font-size: 14px;
            color: var(--color-text-secondary);
            margin-bottom: 12px;
        }
        @media(max-width:767px) {
            #cases .cases-grid {
                grid-template-columns: 1fr;
                gap: 20px;
            }
            #cases .case-card:nth-child(even) {
                margin-top: 0;
            }
        }

        /* Solutions */
        #solutions .solutions-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 28px;
            align-items: stretch;
        }
        #solutions .solution-card {
            background: #FFFFFF;
            border-radius: var(--radius-lg);
            padding: 40px 32px;
            box-shadow: var(--shadow-card);
            display: flex;
            flex-direction: column;
            transition: transform var(--transition-smooth), box-shadow var(--transition-smooth);
        }
        #solutions .solution-card.featured {
            background: var(--color-graphite);
            color: #FFFFFF;
            border: 1.5px solid rgba(0, 229, 161, 0.35);
            position: relative;
        }
        #solutions .solution-card.featured h4,
        #solutions .solution-card.featured .feature-item span {
            color: #FFFFFF;
        }
        #solutions .solution-card h4 {
            font-size: 22px;
            font-weight: 600;
            margin-bottom: 20px;
        }
        #solutions .solution-card .feature-list {
            display: flex;
            flex-direction: column;
            gap: 14px;
            flex: 1;
            margin-bottom: 24px;
        }
        #solutions .solution-card .feature-item {
            display: flex;
            align-items: flex-start;
            gap: 10px;
            font-size: 15px;
            color: var(--color-text-secondary);
        }
        #solutions .solution-card.featured .feature-item {
            color: #CCD0D5;
        }
        #solutions .solution-card .feature-item .icon-check {
            color: var(--color-cyan);
            font-weight: 700;
            flex-shrink: 0;
            font-size: 16px;
            margin-top: 1px;
        }
        #solutions .solution-card .feature-item .icon-dash {
            color: var(--color-text-muted);
            flex-shrink: 0;
            font-weight: 400;
            font-size: 16px;
            margin-top: 1px;
        }
        #solutions .solution-card .btn-wrap {
            margin-top: auto;
        }
        @media(max-width:767px) {
            #solutions .solutions-grid {
                grid-template-columns: 1fr;
            }
            #solutions .solution-card.featured {
                order: -1;
            }
        }

        /* FAQ */
        #faq .faq-wrapper {
            max-width: 800px;
            margin: 0 auto;
        }
        #faq .faq-item {
            border-bottom: 1px solid var(--color-silver);
        }
        #faq .faq-question {
            display: flex;
            align-items: center;
            justify-content: space-between;
            width: 100%;
            padding: 20px 0;
            text-align: left;
            font-size: 20px;
            font-weight: 600;
            color: var(--color-text);
            cursor: pointer;
            transition: color var(--transition-fast);
            gap: 16px;
        }
        #faq .faq-question:hover {
            color: var(--color-cyan);
        }
        #faq .faq-question .faq-icon {
            flex-shrink: 0;
            width: 28px;
            height: 28px;
            border-radius: 50%;
            border: 2px solid var(--color-text-muted);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 18px;
            font-weight: 500;
            transition: transform var(--transition-smooth), border-color var(--transition-fast), color var(--transition-fast);
            line-height: 1;
        }
        #faq .faq-question:hover .faq-icon {
            border-color: var(--color-cyan);
            color: var(--color-cyan);
        }
        #faq .faq-item.open .faq-question .faq-icon {
            transform: rotate(45deg);
            border-color: var(--color-cyan);
            color: var(--color-cyan);
        }
        #faq .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height var(--transition-slow), padding var(--transition-slow);
        }
        #faq .faq-item.open .faq-answer {
            max-height: 300px;
        }
        #faq .faq-answer-inner {
            padding: 0 0 20px;
            font-size: 15px;
            color: var(--color-text-secondary);
            line-height: 1.75;
        }
        @media(max-width:767px) {
            #faq .faq-question {
                font-size: 17px;
            }
        }

        /* CTA */
        #contact {
            background: var(--color-black);
            padding: 80px 0;
            text-align: center;
            position: relative;
            overflow: hidden;
        }
        #contact::before {
            content: '';
            position: absolute;
            inset: 0;
            background: radial-gradient(ellipse at 50% 30%, rgba(0, 229, 161, 0.06) 0%, transparent 70%);
            pointer-events: none;
        }
        #contact .cta-bg-pattern {
            position: absolute;
            inset: 0;
            background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%2300E5A1' fill-opacity='0.04'%3E%3Ccircle cx='30' cy='30' r='1.5'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
            pointer-events: none;
            opacity: 0.7;
        }
        #contact .container {
            position: relative;
            z-index: 1;
        }
        #contact h2 {
            font-size: 40px;
            line-height: 1.3;
            font-weight: 600;
            letter-spacing: -0.01em;
            color: #FFFFFF;
            margin-bottom: 12px;
        }
        #contact .cta-sub {
            font-size: 17px;
            color: var(--color-text-muted);
            margin-bottom: 28px;
        }
        #contact .btn-primary {
            box-shadow: var(--shadow-glow);
            font-size: 16px;
            padding: 16px 40px;
        }
        @media(max-width:767px) {
            #contact h2 {
                font-size: 28px;
            }
            #contact {
                padding: 60px 0;
            }
        }

        /* Footer */
        #footer {
            background: var(--color-black);
            color: var(--color-text-muted);
            padding: 56px 0 24px;
            border-top: 1px solid rgba(255, 255, 255, 0.06);
        }
        #footer .footer-grid {
            display: grid;
            grid-template-columns: 3fr 2fr 2fr 3fr;
            gap: 32px;
            margin-bottom: 40px;
        }
        #footer .footer-col .footer-logo {
            display: flex;
            align-items: center;
            gap: 8px;
            font-weight: 700;
            font-size: 18px;
            color: #FFFFFF;
            margin-bottom: 12px;
        }
        #footer .footer-col .footer-logo svg {
            width: 28px;
            height: 28px;
        }
        #footer .footer-col p {
            font-size: 14px;
            line-height: 1.7;
        }
        #footer .footer-col h5 {
            font-size: 15px;
            font-weight: 600;
            color: #FFFFFF;
            margin-bottom: 14px;
            letter-spacing: 0.01em;
        }
        #footer .footer-col a {
            display: block;
            font-size: 14px;
            color: var(--color-text-muted);
            padding: 4px 0;
            transition: color var(--transition-fast);
        }
        #footer .footer-col a:hover {
            color: var(--color-cyan);
        }
        #footer .footer-bottom {
            text-align: center;
            font-size: 12px;
            color: var(--color-text-muted);
            padding-top: 20px;
            border-top: 1px solid rgba(255, 255, 255, 0.08);
        }
        #footer .social-dots {
            display: flex;
            gap: 12px;
            flex-wrap: wrap;
        }
        #footer .social-dots .social-circle {
            width: 36px;
            height: 36px;
            border-radius: 50%;
            border: 1.5px solid rgba(255, 255, 255, 0.2);
            display: flex;
            align-items: center;
            justify-content: center;
            transition: border-color var(--transition-fast), background var(--transition-fast);
            cursor: pointer;
            color: var(--color-text-muted);
            font-size: 14px;
        }
        #footer .social-dots .social-circle:hover {
            border-color: var(--color-cyan);
            background: rgba(0, 229, 161, 0.08);
            color: var(--color-cyan);
        }
        @media(max-width:1023px) {
            #footer .footer-grid {
                grid-template-columns: 1fr 1fr;
            }
        }
        @media(max-width:767px) {
            #footer .footer-grid {
                grid-template-columns: 1fr;
                gap: 24px;
            }
        }