/* roulang page: index */
:root {
            --color-primary: #FF5F1F;
            --color-primary-hover: #E04D0F;
            --color-primary-light: rgba(255, 95, 31, 0.10);
            --color-primary-glow: rgba(255, 95, 31, 0.35);
            --color-dark: #1C1C1E;
            --color-dark-solid: #141416;
            --color-light-bg: #F2F2F4;
            --color-light-card: #FAFAFB;
            --color-white: #FFFFFF;
            --color-success: #2ECC71;
            --color-danger: #E74C3C;
            --color-text-primary: #0B0B0C;
            --color-text-secondary: #6B6B70;
            --color-text-light: #9A9AA0;
            --color-border: #E5E5EA;
            --radius-sm: 6px;
            --radius-md: 8px;
            --radius-lg: 12px;
            --radius-xl: 30px;
            --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.04), 0 4px 16px rgba(0, 0, 0, 0.04);
            --shadow-card-hover: 0 6px 20px rgba(0, 0, 0, 0.08), 0 8px 32px rgba(0, 0, 0, 0.06);
            --shadow-nav: 0 1px 6px rgba(0, 0, 0, 0.12);
            --font-stack: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', sans-serif;
            --nav-height: 64px;
            --section-padding: 5rem 0;
            --container-max: 1200px;
            --container-padding: 1.5rem;
            --transition-fast: 0.2s ease;
            --transition-smooth: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
        }

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

        html {
            scroll-behavior: smooth;
            scroll-padding-top: var(--nav-height);
            -webkit-text-size-adjust: 100%;
        }

        body {
            font-family: var(--font-stack);
            font-size: 1rem;
            font-weight: 400;
            line-height: 1.7;
            color: var(--color-text-primary);
            background-color: var(--color-white);
            min-width: 320px;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

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

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

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

        input {
            font-family: inherit;
            font-size: 1rem;
            outline: none;
            border: 1px solid var(--color-border);
            border-radius: var(--radius-md);
            padding: 0.75rem 1rem;
            width: 100%;
            transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
            background: var(--color-white);
        }

        input:focus {
            border-color: var(--color-primary);
            box-shadow: 0 0 0 3px var(--color-primary-light);
        }

        input::placeholder {
            color: var(--color-text-light);
            font-size: 0.9rem;
        }

        .container {
            max-width: var(--container-max);
            margin: 0 auto;
            padding: 0 var(--container-padding);
        }

        .section-tag {
            display: inline-block;
            font-size: 0.8rem;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 0.08em;
            color: var(--color-primary);
            background: var(--color-primary-light);
            padding: 0.3rem 0.9rem;
            border-radius: 20px;
            margin-bottom: 1rem;
        }

        .section-title {
            font-size: clamp(1.75rem, 3.5vw, 2.5rem);
            font-weight: 800;
            color: var(--color-text-primary);
            line-height: 1.3;
            margin-bottom: 1rem;
            letter-spacing: -0.02em;
        }

        .section-subtitle {
            font-size: 1.05rem;
            color: var(--color-text-secondary);
            max-width: 620px;
            line-height: 1.65;
            margin-bottom: 2.5rem;
        }

        .text-center {
            text-align: center;
        }
        .text-center .section-subtitle {
            margin-left: auto;
            margin-right: auto;
        }

        /* ========== NAVIGATION ========== */
        #main-nav {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 1000;
            height: var(--nav-height);
            background: rgba(28, 28, 30, 0.85);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            transition: background var(--transition-smooth), box-shadow var(--transition-smooth);
            display: flex;
            align-items: center;
        }

        #main-nav.scrolled {
            background: var(--color-dark);
            box-shadow: var(--shadow-nav);
        }

        #main-nav .nav-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            width: 100%;
            max-width: var(--container-max);
            margin: 0 auto;
            padding: 0 var(--container-padding);
        }

        .nav-logo {
            font-size: 1.35rem;
            font-weight: 900;
            color: var(--color-primary);
            letter-spacing: -0.01em;
            white-space: nowrap;
            flex-shrink: 0;
        }
        .nav-logo:hover {
            color: #FF8C42;
        }

        .nav-links {
            display: flex;
            align-items: center;
            gap: 2rem;
            list-style: none;
        }

        .nav-links a {
            font-size: 0.925rem;
            font-weight: 500;
            color: rgba(255, 255, 255, 0.85);
            position: relative;
            transition: color var(--transition-fast);
            padding: 0.25rem 0;
        }

        .nav-links a::after {
            content: '';
            position: absolute;
            bottom: -3px;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--color-primary);
            border-radius: 2px;
            transition: width var(--transition-fast);
        }

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

        .hamburger {
            display: none;
            flex-direction: column;
            gap: 5px;
            cursor: pointer;
            z-index: 1001;
            padding: 4px;
        }
        .hamburger span {
            display: block;
            width: 26px;
            height: 2.5px;
            background: #FFFFFF;
            border-radius: 2px;
            transition: all var(--transition-fast);
        }

        .hamburger.open span:nth-child(1) {
            transform: rotate(45deg) translate(5px, 5px);
        }
        .hamburger.open span:nth-child(2) {
            opacity: 0;
        }
        .hamburger.open span:nth-child(3) {
            transform: rotate(-45deg) translate(5px, -5px);
        }

        .mobile-menu {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: var(--color-dark);
            z-index: 999;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            gap: 2.2rem;
            list-style: none;
            opacity: 0;
            pointer-events: none;
            transition: opacity var(--transition-smooth);
        }
        .mobile-menu.open {
            opacity: 1;
            pointer-events: all;
        }
        .mobile-menu a {
            font-size: 1.4rem;
            font-weight: 700;
            color: #FFFFFF;
            transition: color var(--transition-fast);
        }
        .mobile-menu a:hover {
            color: var(--color-primary);
        }

        /* ========== HERO ========== */
        #hero {
            position: relative;
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            overflow: hidden;
            background: var(--color-dark-solid);
        }

        #hero .hero-bg {
            position: absolute;
            inset: 0;
            z-index: 0;
            background:
                radial-gradient(ellipse at 50% 35%, rgba(28, 28, 30, 0.3) 0%, rgba(20, 20, 22, 0.85) 75%),
                linear-gradient(180deg, rgba(28, 28, 30, 0.55) 0%, rgba(20, 20, 22, 0.9) 100%),
                url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
        }

        #hero .hero-content {
            position: relative;
            z-index: 2;
            max-width: 720px;
            padding: 2rem var(--container-padding);
        }

        #hero h1 {
            font-size: clamp(2.5rem, 5vw, 4rem);
            font-weight: 900;
            color: #FFFFFF;
            line-height: 1.2;
            letter-spacing: -0.03em;
            margin-bottom: 1.2rem;
        }
        #hero h1 .highlight {
            color: var(--color-primary);
        }

        #hero .hero-subtitle {
            font-size: 1.15rem;
            color: rgba(255, 255, 255, 0.75);
            max-width: 580px;
            margin: 0 auto 2.5rem;
            line-height: 1.6;
        }

        .hero-buttons {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
            justify-content: center;
        }

        .btn {
            display: inline-block;
            font-weight: 600;
            font-size: 0.95rem;
            padding: 0.75rem 2rem;
            border-radius: var(--radius-sm);
            transition: all var(--transition-fast);
            text-align: center;
            white-space: nowrap;
            cursor: pointer;
            border: 2px solid transparent;
        }

        .btn-primary {
            background: var(--color-primary);
            color: #FFFFFF;
            border-color: var(--color-primary);
        }
        .btn-primary:hover {
            background: var(--color-primary-hover);
            border-color: var(--color-primary-hover);
            transform: scale(1.03);
            box-shadow: 0 4px 18px var(--color-primary-glow);
        }

        .btn-outline {
            background: transparent;
            color: #FFFFFF;
            border-color: rgba(255, 255, 255, 0.5);
        }
        .btn-outline:hover {
            background: rgba(255, 255, 255, 0.08);
            border-color: #FFFFFF;
            transform: scale(1.03);
        }

        .btn-cta {
            background: linear-gradient(135deg, #FF5F1F 0%, #FF8C42 100%);
            color: #FFFFFF;
            border: none;
            border-radius: var(--radius-xl);
            padding: 0.9rem 2.8rem;
            font-size: 1.05rem;
            font-weight: 700;
            letter-spacing: 0.02em;
            box-shadow: 0 4px 20px rgba(255, 95, 31, 0.3);
            transition: all var(--transition-fast);
        }
        .btn-cta:hover {
            box-shadow: 0 8px 32px rgba(255, 95, 31, 0.5);
            transform: translateY(-2px) scale(1.04);
        }

        /* ========== DASHBOARD ========== */
        #dashboard {
            padding: var(--section-padding);
            background: var(--color-white);
        }

        #dashboard .dashboard-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 1.5rem;
            max-width: var(--container-max);
            margin: 0 auto;
            padding: 0 var(--container-padding);
        }

        .stat-card {
            background: var(--color-light-card);
            border-radius: var(--radius-lg);
            padding: 1.8rem 1.5rem;
            box-shadow: var(--shadow-card);
            position: relative;
            overflow: hidden;
            transition: all var(--transition-fast);
            border-left: 4px solid var(--color-primary);
        }
        .stat-card:hover {
            box-shadow: var(--shadow-card-hover);
            transform: translateY(-2px);
        }
        .stat-card .stat-number {
            font-size: 2.6rem;
            font-weight: 900;
            color: var(--color-primary);
            line-height: 1;
            margin-bottom: 0.5rem;
            letter-spacing: -0.03em;
        }
        .stat-card .stat-label {
            font-size: 0.875rem;
            color: var(--color-text-secondary);
            font-weight: 500;
            line-height: 1.4;
        }

        /* ========== SERVICES ========== */
        #services {
            padding: var(--section-padding);
            background: var(--color-light-bg);
        }

        #services .services-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 1.5rem;
            max-width: var(--container-max);
            margin: 0 auto;
            padding: 0 var(--container-padding);
        }

        .service-card {
            background: var(--color-white);
            border-radius: var(--radius-lg);
            overflow: hidden;
            box-shadow: var(--shadow-card);
            transition: all var(--transition-fast);
            display: flex;
            flex-direction: column;
        }
        .service-card:hover {
            box-shadow: var(--shadow-card-hover);
            transform: translateY(-3px);
        }
        .service-card.span-2 {
            grid-column: span 2;
        }
        .service-card.span-1 {
            grid-column: span 1;
        }
        .service-card.span-3 {
            grid-column: span 3;
        }

        .service-card .card-img {
            width: 100%;
            height: 200px;
            object-fit: cover;
            display: block;
            background: var(--color-light-bg);
        }
        .service-card.span-2 .card-img {
            height: 240px;
        }

        .service-card .card-body {
            padding: 1.5rem;
            flex: 1;
            display: flex;
            flex-direction: column;
        }
        .service-card .card-body h3 {
            font-size: 1.2rem;
            font-weight: 700;
            color: var(--color-text-primary);
            margin-bottom: 0.5rem;
            line-height: 1.35;
        }
        .service-card .card-body p {
            font-size: 0.9rem;
            color: var(--color-text-secondary);
            line-height: 1.6;
            flex: 1;
        }
        .service-card .card-icon-dot {
            display: inline-block;
            width: 10px;
            height: 10px;
            background: var(--color-primary);
            border-radius: 50%;
            margin-bottom: 0.75rem;
            opacity: 0.7;
        }

        /* ========== COMPARISON ========== */
        #comparison {
            padding: var(--section-padding);
            background: var(--color-white);
        }

        #comparison .comparison-wrapper {
            display: flex;
            align-items: stretch;
            gap: 0;
            max-width: 900px;
            margin: 0 auto;
            padding: 0 var(--container-padding);
            position: relative;
            background: var(--color-light-bg);
            border-radius: var(--radius-lg);
            overflow: hidden;
            box-shadow: var(--shadow-card);
        }

        .comparison-col {
            flex: 1;
            padding: 2.5rem 2rem;
        }
        .comparison-col.old {
            background: #FAFAFB;
        }
        .comparison-col.new {
            background: #FFFBF8;
        }
        .comparison-col h3 {
            font-size: 1.3rem;
            font-weight: 800;
            margin-bottom: 1.5rem;
            text-align: center;
            letter-spacing: -0.01em;
        }
        .comparison-col.old h3 {
            color: var(--color-text-secondary);
        }
        .comparison-col.new h3 {
            color: var(--color-primary);
        }

        .comparison-divider {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 60px;
            flex-shrink: 0;
            background: var(--color-white);
            z-index: 1;
            font-weight: 900;
            font-size: 0.9rem;
            color: var(--color-text-light);
            letter-spacing: 0.05em;
        }
        .comparison-divider .vs-badge {
            background: var(--color-dark);
            color: #FFFFFF;
            width: 44px;
            height: 44px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 900;
            font-size: 0.85rem;
            letter-spacing: 0.04em;
            box-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
        }

        .comparison-row {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            padding: 0.7rem 0;
            border-bottom: 1px solid rgba(0, 0, 0, 0.04);
            font-size: 0.925rem;
            color: var(--color-text-primary);
        }
        .comparison-row:last-child {
            border-bottom: none;
        }
        .comparison-row .icon-fail {
            color: var(--color-danger);
            font-weight: 700;
            flex-shrink: 0;
            font-size: 1.1rem;
        }
        .comparison-row .icon-pass {
            color: var(--color-success);
            font-weight: 700;
            flex-shrink: 0;
            font-size: 1.1rem;
        }

        /* ========== FAQ ========== */
        #faq {
            padding: var(--section-padding);
            background: var(--color-light-bg);
        }

        #faq .faq-list {
            max-width: 720px;
            margin: 0 auto;
            padding: 0 var(--container-padding);
            display: flex;
            flex-direction: column;
            gap: 0.75rem;
        }

        .faq-item {
            background: var(--color-white);
            border-radius: var(--radius-md);
            box-shadow: var(--shadow-card);
            overflow: hidden;
            transition: box-shadow var(--transition-fast);
        }
        .faq-item:hover {
            box-shadow: var(--shadow-card-hover);
        }
        .faq-question {
            width: 100%;
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 1.2rem 1.5rem;
            font-size: 1.05rem;
            font-weight: 700;
            color: var(--color-primary);
            cursor: pointer;
            text-align: left;
            background: none;
            border: none;
            gap: 1rem;
            line-height: 1.4;
        }
        .faq-question .faq-icon {
            flex-shrink: 0;
            font-size: 1.3rem;
            font-weight: 400;
            transition: transform var(--transition-smooth);
            color: var(--color-primary);
            width: 28px;
            height: 28px;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height var(--transition-smooth), padding var(--transition-smooth);
            padding: 0 1.5rem;
            color: var(--color-text-secondary);
            font-size: 0.95rem;
            line-height: 1.7;
        }
        .faq-item.open .faq-answer {
            max-height: 300px;
            padding: 0 1.5rem 1.2rem;
        }
        .faq-item.open .faq-icon {
            transform: rotate(45deg);
        }

        /* ========== CTA ========== */
        #cta {
            padding: var(--section-padding);
            background: linear-gradient(180deg, var(--color-dark) 0%, #0B0B0C 100%);
        }

        #cta .cta-card {
            max-width: 560px;
            margin: 0 auto;
            background: var(--color-white);
            border-radius: var(--radius-lg);
            padding: 3rem 2.5rem;
            box-shadow: 0 8px 40px rgba(0, 0, 0, 0.25);
        }
        #cta .cta-card h2 {
            font-size: 1.75rem;
            font-weight: 800;
            color: var(--color-text-primary);
            margin-bottom: 0.5rem;
            text-align: center;
            letter-spacing: -0.02em;
        }
        #cta .cta-card .cta-desc {
            font-size: 0.95rem;
            color: var(--color-text-secondary);
            text-align: center;
            margin-bottom: 2rem;
            line-height: 1.6;
        }
        .form-group {
            margin-bottom: 1.2rem;
        }
        .form-group label {
            display: block;
            font-size: 0.85rem;
            font-weight: 600;
            color: var(--color-text-primary);
            margin-bottom: 0.35rem;
        }
        .captcha-box {
            display: flex;
            align-items: center;
            gap: 0.75rem;
        }
        .captcha-display {
            flex-shrink: 0;
            width: 90px;
            height: 44px;
            background: #F5F5F7;
            border-radius: var(--radius-sm);
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 1.2rem;
            letter-spacing: 0.06em;
            color: var(--color-text-primary);
            user-select: none;
            border: 1px dashed var(--color-border);
            cursor: pointer;
            transition: background var(--transition-fast);
            font-style: italic;
        }
        .captcha-display:hover {
            background: #EBEBEE;
        }
        .captcha-box input {
            flex: 1;
        }
        .trust-badges {
            display: flex;
            justify-content: center;
            gap: 1.5rem;
            flex-wrap: wrap;
            margin-top: 1.5rem;
            font-size: 0.8rem;
            color: var(--color-text-light);
        }
        .trust-badges span {
            display: flex;
            align-items: center;
            gap: 0.35rem;
        }
        .trust-badges i {
            color: var(--color-success);
            font-size: 0.85rem;
        }

        /* ========== FOOTER ========== */
        #footer {
            background: var(--color-dark);
            padding: 3.5rem 0 1.5rem;
            color: var(--color-text-secondary);
        }
        #footer .footer-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 2rem;
            max-width: var(--container-max);
            margin: 0 auto 3rem;
            padding: 0 var(--container-padding);
        }
        #footer .footer-col h4 {
            font-size: 0.9rem;
            font-weight: 700;
            color: #FFFFFF;
            margin-bottom: 1rem;
            letter-spacing: 0.03em;
        }
        #footer .footer-col ul {
            list-style: none;
            display: flex;
            flex-direction: column;
            gap: 0.55rem;
        }
        #footer .footer-col ul li a {
            font-size: 0.875rem;
            color: var(--color-text-secondary);
            transition: color var(--transition-fast);
        }
        #footer .footer-col ul li a:hover {
            color: var(--color-primary);
        }
        #footer .footer-logo {
            font-size: 1.3rem;
            font-weight: 900;
            color: var(--color-primary);
            margin-bottom: 0.75rem;
            display: inline-block;
        }
        #footer .footer-copy {
            text-align: center;
            font-size: 0.8rem;
            color: var(--color-text-light);
            padding: 1.5rem var(--container-padding) 0;
            border-top: 1px solid rgba(255, 255, 255, 0.08);
            max-width: var(--container-max);
            margin: 0 auto;
        }

        /* ========== RESPONSIVE ========== */
        @media (max-width: 1024px) {
            #dashboard .dashboard-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            #services .services-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            #services .service-card.span-2,
            #services .service-card.span-3 {
                grid-column: span 2;
            }
            #services .service-card.span-1 {
                grid-column: span 1;
            }
            .comparison-wrapper {
                flex-direction: column;
                gap: 0;
            }
            .comparison-divider {
                width: 100%;
                height: 50px;
                flex-direction: row;
            }
            .comparison-divider .vs-badge {
                width: 38px;
                height: 38px;
                font-size: 0.75rem;
            }
            #footer .footer-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        @media (max-width: 768px) {
            :root {
                --section-padding: 3.5rem 0;
                --container-padding: 1.2rem;
            }
            .nav-links {
                display: none;
            }
            .hamburger {
                display: flex;
            }
            .mobile-menu {
                display: flex;
            }
            #hero h1 {
                font-size: clamp(2rem, 7vw, 2.8rem);
            }
            #hero .hero-subtitle {
                font-size: 1rem;
            }
            #dashboard .dashboard-grid {
                grid-template-columns: 1fr;
                gap: 1rem;
            }
            .stat-card {
                padding: 1.4rem 1.2rem;
            }
            .stat-card .stat-number {
                font-size: 2.2rem;
            }
            #services .services-grid {
                grid-template-columns: 1fr;
            }
            #services .service-card.span-2,
            #services .service-card.span-3,
            #services .service-card.span-1 {
                grid-column: span 1;
            }
            .service-card .card-img {
                height: 180px;
            }
            .service-card.span-2 .card-img {
                height: 180px;
            }
            .comparison-col {
                padding: 1.5rem;
            }
            #cta .cta-card {
                padding: 2rem 1.5rem;
            }
            #footer .footer-grid {
                grid-template-columns: 1fr 1fr;
                gap: 1.5rem;
            }
            .hero-buttons {
                flex-direction: column;
                align-items: center;
            }
            .hero-buttons .btn {
                width: 100%;
                max-width: 280px;
            }
        }

        @media (max-width: 520px) {
            #footer .footer-grid {
                grid-template-columns: 1fr;
                gap: 1.2rem;
            }
            .comparison-row {
                font-size: 0.85rem;
                gap: 0.5rem;
            }
            .trust-badges {
                gap: 0.75rem;
                font-size: 0.72rem;
            }
        }