/* roulang page: index */
:root {
            --primary: #8B5CF6;
            --primary-light: #9B6DF7;
            --primary-glow: rgba(139, 92, 246, 0.5);
            --primary-subtle: rgba(139, 92, 246, 0.12);
            --accent: #06B6D4;
            --accent-glow: rgba(6, 182, 212, 0.45);
            --accent-subtle: rgba(6, 182, 212, 0.15);
            --bg-deep: #0A0A12;
            --bg-card: #111122;
            --bg-darker: #06060E;
            --bg-nav: rgba(10, 10, 18, 0.85);
            --text-primary: #F1F0FB;
            --text-secondary: #A0A0B8;
            --text-muted: #6B6B80;
            --success: #22D65D;
            --warning: #F97316;
            --border-subtle: rgba(255, 255, 255, 0.06);
            --border-light: rgba(255, 255, 255, 0.1);
            --border-primary: rgba(139, 92, 246, 0.35);
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 16px;
            --radius-xl: 20px;
            --radius-full: 9999px;
            --shadow-card: 0 4px 24px rgba(139, 92, 246, 0.08);
            --shadow-card-hover: 0 8px 40px rgba(6, 182, 212, 0.2);
            --shadow-btn-primary: 0 0 24px rgba(139, 92, 246, 0.5);
            --shadow-img-glow: 0 0 36px rgba(139, 92, 246, 0.35);
            --font-h1: 700 48px/56px 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
            --font-h2: 600 36px/44px 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
            --font-h3: 600 24px/32px 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
            --font-h4: 600 20px/28px 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
            --font-body: 400 16px/26px 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
            --font-small: 400 13px/20px 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
            --font-btn: 600 16px/1.2 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
            --font-mono: 'Inter', 'SF Pro Display', system-ui, sans-serif;
            --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
            --transition-smooth: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
            --transition-slow: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
            --container-max: 1280px;
            --container-px: 24px;
            --section-py: 100px;
            --section-py-mobile: 60px;
            --nav-height: 72px;
            --nav-height-mobile: 56px;
            --letter-spacing-h1: -0.02em;
            --letter-spacing-btn: 0.05em;
        }

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

        html {
            scroll-behavior: smooth;
            scroll-padding-top: var(--nav-height);
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

        body {
            font: var(--font-body);
            color: var(--text-primary);
            background-color: var(--bg-deep);
            min-height: 100vh;
            letter-spacing: 0.01em;
        }

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

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

        button,
        input,
        textarea {
            font-family: inherit;
            font-size: inherit;
            border: none;
            outline: none;
            background: none;
        }
        button {
            cursor: pointer;
        }
        input,
        textarea {
            color: var(--text-primary);
        }

        ::selection {
            background: var(--primary);
            color: #fff;
        }

        ::-webkit-scrollbar {
            width: 6px;
            height: 6px;
        }
        ::-webkit-scrollbar-track {
            background: var(--bg-deep);
        }
        ::-webkit-scrollbar-thumb {
            background: var(--border-primary);
            border-radius: var(--radius-full);
        }
        ::-webkit-scrollbar-thumb:hover {
            background: var(--primary);
        }

        .container {
            max-width: var(--container-max);
            margin: 0 auto;
            padding: 0 var(--container-px);
            width: 100%;
        }

        /* ========== 导航 ========== */
        .nav {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 1000;
            height: var(--nav-height);
            display: flex;
            align-items: center;
            transition: background var(--transition-smooth), box-shadow var(--transition-smooth), backdrop-filter var(--transition-smooth);
            background: transparent;
            border-bottom: 1px solid transparent;
        }
        .nav.scrolled {
            background: var(--bg-nav);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            border-bottom: 1px solid var(--border-primary);
            box-shadow: 0 2px 20px rgba(0, 0, 0, 0.5);
        }
        .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-px);
            height: 100%;
        }
        .nav-logo {
            display: flex;
            align-items: center;
            gap: 10px;
            font-size: 22px;
            font-weight: 700;
            letter-spacing: 0.03em;
            color: var(--text-primary);
            white-space: nowrap;
            text-decoration: none;
            flex-shrink: 0;
        }
        .nav-logo:hover {
            color: var(--text-primary);
        }
        .nav-logo-icon {
            width: 32px;
            height: 32px;
            background: var(--primary);
            transform: rotate(45deg);
            border-radius: 4px;
            flex-shrink: 0;
            box-shadow: 0 0 16px rgba(139, 92, 246, 0.55);
            animation: logoPulse 3s ease-in-out infinite;
        }
        @keyframes logoPulse {
            0%,
            100% {
                box-shadow: 0 0 16px rgba(139, 92, 246, 0.55);
            }
            50% {
                box-shadow: 0 0 28px rgba(139, 92, 246, 0.85), 0 0 50px rgba(6, 182, 212, 0.3);
            }
        }
        .nav-links {
            display: flex;
            align-items: center;
            gap: 32px;
            list-style: none;
        }
        .nav-links a {
            font-size: 15px;
            font-weight: 500;
            color: var(--text-secondary);
            letter-spacing: 0.02em;
            position: relative;
            padding: 6px 0;
            transition: color var(--transition-fast);
        }
        .nav-links a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--accent);
            border-radius: 1px;
            transition: width var(--transition-smooth);
            box-shadow: 0 0 8px var(--accent-glow);
        }
        .nav-links a:hover,
        .nav-links a.active {
            color: var(--text-primary);
        }
        .nav-links a:hover::after,
        .nav-links a.active::after {
            width: 100%;
        }
        .nav-cta {
            display: flex;
            align-items: center;
            gap: 12px;
            flex-shrink: 0;
        }
        .btn-nav {
            padding: 10px 22px;
            border-radius: var(--radius-sm);
            font-weight: 600;
            font-size: 14px;
            letter-spacing: var(--letter-spacing-btn);
            transition: all var(--transition-smooth);
            background: var(--primary);
            color: #fff;
            white-space: nowrap;
        }
        .btn-nav:hover {
            background: var(--primary-light);
            box-shadow: var(--shadow-btn-primary);
            color: #fff;
        }
        .nav-hamburger {
            display: none;
            flex-direction: column;
            gap: 5px;
            cursor: pointer;
            z-index: 1001;
            padding: 8px;
            background: none;
            border: none;
        }
        .nav-hamburger span {
            display: block;
            width: 24px;
            height: 2px;
            background: var(--text-primary);
            border-radius: 1px;
            transition: all var(--transition-smooth);
        }
        .nav-hamburger.active span:nth-child(1) {
            transform: rotate(45deg) translate(5px, 5px);
        }
        .nav-hamburger.active span:nth-child(2) {
            opacity: 0;
        }
        .nav-hamburger.active span:nth-child(3) {
            transform: rotate(-45deg) translate(5px, -5px);
        }
        .nav-mobile-overlay {
            display: none;
            position: fixed;
            inset: 0;
            background: rgba(6, 6, 14, 0.95);
            backdrop-filter: blur(16px);
            -webkit-backdrop-filter: blur(16px);
            z-index: 999;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            gap: 36px;
            opacity: 0;
            pointer-events: none;
            transition: opacity var(--transition-smooth);
        }
        .nav-mobile-overlay.open {
            opacity: 1;
            pointer-events: auto;
        }
        .nav-mobile-overlay a {
            font-size: 20px;
            font-weight: 600;
            color: var(--text-primary);
            letter-spacing: 0.04em;
            padding: 10px 28px;
            border-left: 3px solid transparent;
            transition: all var(--transition-fast);
        }
        .nav-mobile-overlay a:hover,
        .nav-mobile-overlay a:focus {
            border-left-color: var(--accent);
            color: var(--accent);
        }

        /* ========== Hero ========== */
        .hero {
            min-height: 90vh;
            display: flex;
            align-items: center;
            padding-top: var(--nav-height);
            position: relative;
            overflow: hidden;
            background: var(--bg-deep);
        }
        .hero-particles {
            position: absolute;
            inset: 0;
            pointer-events: none;
            z-index: 0;
        }
        .hero-particle {
            position: absolute;
            border-radius: 50%;
            opacity: 0.18;
            animation: floatParticle 12s ease-in-out infinite;
        }
        .hero-particle:nth-child(1) {
            width: 4px;
            height: 4px;
            background: var(--primary);
            top: 18%;
            left: 10%;
            animation-delay: 0s;
            animation-duration: 14s;
            box-shadow: 0 0 12px var(--primary-glow);
        }
        .hero-particle:nth-child(2) {
            width: 3px;
            height: 3px;
            background: var(--accent);
            top: 30%;
            right: 15%;
            animation-delay: 2s;
            animation-duration: 16s;
            box-shadow: 0 0 10px var(--accent-glow);
        }
        .hero-particle:nth-child(3) {
            width: 5px;
            height: 5px;
            background: var(--primary);
            top: 65%;
            left: 25%;
            animation-delay: 4s;
            animation-duration: 18s;
            box-shadow: 0 0 14px var(--primary-glow);
        }
        .hero-particle:nth-child(4) {
            width: 3px;
            height: 3px;
            background: var(--accent);
            bottom: 20%;
            right: 30%;
            animation-delay: 1s;
            animation-duration: 13s;
            box-shadow: 0 0 9px var(--accent-glow);
        }
        .hero-particle:nth-child(5) {
            width: 4px;
            height: 4px;
            background: var(--primary);
            top: 50%;
            left: 60%;
            animation-delay: 6s;
            animation-duration: 15s;
            box-shadow: 0 0 11px var(--primary-glow);
        }
        @keyframes floatParticle {
            0%,
            100% {
                transform: translateY(0) translateX(0) scale(1);
                opacity: 0.18;
            }
            25% {
                transform: translateY(-30px) translateX(20px) scale(1.5);
                opacity: 0.3;
            }
            50% {
                transform: translateY(-10px) translateX(-15px) scale(0.8);
                opacity: 0.14;
            }
            75% {
                transform: translateY(-40px) translateX(10px) scale(1.6);
                opacity: 0.25;
            }
        }
        .hero-grid-bg {
            position: absolute;
            inset: 0;
            pointer-events: none;
            z-index: 0;
            background-image:
                linear-gradient(rgba(139, 92, 246, 0.04) 1px, transparent 1px),
                linear-gradient(90deg, rgba(139, 92, 246, 0.04) 1px, transparent 1px);
            background-size: 60px 60px;
            mask-image: radial-gradient(ellipse at center, black 35%, transparent 70%);
            -webkit-mask-image: radial-gradient(ellipse at center, black 35%, transparent 70%);
        }
        .hero .container {
            position: relative;
            z-index: 1;
            display: grid;
            grid-template-columns: 55% 40%;
            gap: 40px;
            align-items: center;
        }
        .hero-content {
            display: flex;
            flex-direction: column;
            gap: 22px;
        }
        .hero-badge {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            font-size: 13px;
            font-weight: 600;
            color: var(--accent);
            background: var(--accent-subtle);
            border-radius: var(--radius-full);
            padding: 6px 16px;
            width: fit-content;
            letter-spacing: 0.04em;
            border: 1px solid rgba(6, 182, 212, 0.25);
        }
        .hero-badge-dot {
            width: 7px;
            height: 7px;
            border-radius: 50%;
            background: var(--accent);
            box-shadow: 0 0 8px var(--accent-glow);
            animation: dotBlink 2s ease-in-out infinite;
        }
        @keyframes dotBlink {
            0%,
            100% {
                opacity: 1;
            }
            50% {
                opacity: 0.35;
            }
        }
        .hero h1 {
            font: var(--font-h1);
            letter-spacing: var(--letter-spacing-h1);
            color: var(--text-primary);
            margin: 0;
        }
        .hero h1 .highlight {
            color: var(--primary);
            position: relative;
        }
        .hero h2 {
            font: var(--font-h2);
            font-weight: 400;
            color: var(--text-secondary);
            margin: 0;
            font-size: 20px;
            line-height: 30px;
        }
        .hero-buttons {
            display: flex;
            gap: 16px;
            flex-wrap: wrap;
            margin-top: 8px;
        }
        .btn-primary {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 14px 32px;
            border-radius: var(--radius-sm);
            font: var(--font-btn);
            letter-spacing: var(--letter-spacing-btn);
            background: var(--primary);
            color: #fff;
            transition: all var(--transition-smooth);
            white-space: nowrap;
            text-align: center;
            border: 2px solid transparent;
        }
        .btn-primary:hover {
            background: var(--primary-light);
            box-shadow: var(--shadow-btn-primary);
            color: #fff;
            transform: translateY(-1px);
        }
        .btn-primary:focus-visible {
            outline: 3px solid var(--accent);
            outline-offset: 3px;
            border-radius: var(--radius-sm);
        }
        .btn-outline {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 14px 32px;
            border-radius: var(--radius-sm);
            font: var(--font-btn);
            letter-spacing: var(--letter-spacing-btn);
            background: transparent;
            color: var(--primary);
            border: 2px solid var(--primary);
            transition: all var(--transition-smooth);
            white-space: nowrap;
            text-align: center;
        }
        .btn-outline:hover {
            background: var(--primary);
            color: #fff;
            box-shadow: var(--shadow-btn-primary);
            transform: translateY(-1px);
        }
        .btn-outline:focus-visible {
            outline: 3px solid var(--accent);
            outline-offset: 3px;
            border-radius: var(--radius-sm);
        }
        .btn-accent {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 14px 32px;
            border-radius: var(--radius-sm);
            font: var(--font-btn);
            letter-spacing: var(--letter-spacing-btn);
            background: var(--accent);
            color: var(--bg-deep);
            border: 2px solid transparent;
            transition: all var(--transition-smooth);
            white-space: nowrap;
            text-align: center;
            font-weight: 700;
        }
        .btn-accent:hover {
            box-shadow: 0 0 28px var(--accent-glow);
            color: var(--bg-deep);
            transform: translateY(-1px);
        }
        .btn-accent:focus-visible {
            outline: 3px solid var(--primary);
            outline-offset: 3px;
            border-radius: var(--radius-sm);
        }
        .hero-visual {
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        .hero-visual-frame {
            width: 100%;
            aspect-ratio: 4/5;
            border-radius: var(--radius-lg);
            overflow: hidden;
            position: relative;
            box-shadow: var(--shadow-img-glow);
            border: 1px solid var(--border-primary);
            background: var(--bg-card);
        }
        .hero-visual-frame img {
            width: 100%;
            height: 100%;
            object-fit: cover;
            display: block;
        }
        .hero-visual-frame::after {
            content: '';
            position: absolute;
            inset: 0;
            border-radius: var(--radius-lg);
            box-shadow: inset 0 0 40px rgba(139, 92, 246, 0.2);
            pointer-events: none;
        }
        .hero-visual-glow {
            position: absolute;
            width: 140%;
            height: 140%;
            border-radius: 50%;
            background: radial-gradient(circle, rgba(139, 92, 246, 0.2) 0%, transparent 70%);
            pointer-events: none;
            z-index: -1;
            top: -20%;
            left: -20%;
        }

        /* ========== Section 通用 ========== */
        section {
            padding: var(--section-py) 0;
            position: relative;
        }
        .section-header {
            text-align: center;
            margin-bottom: 56px;
        }
        .section-label {
            display: inline-block;
            font: var(--font-small);
            font-weight: 600;
            color: var(--accent);
            letter-spacing: 0.06em;
            text-transform: uppercase;
            margin-bottom: 12px;
            background: var(--accent-subtle);
            padding: 5px 14px;
            border-radius: var(--radius-full);
        }
        .section-header h2 {
            font: var(--font-h2);
            color: var(--text-primary);
            margin: 0 0 10px;
            letter-spacing: -0.01em;
        }
        .section-header p {
            font: var(--font-body);
            color: var(--text-secondary);
            max-width: 600px;
            margin: 0 auto;
        }

        /* ========== Highlights ========== */
        #highlights {
            background: var(--bg-darker);
            position: relative;
        }
        #highlights::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 1px;
            background: linear-gradient(90deg, transparent, var(--border-primary), transparent);
        }
        .highlights-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 24px;
        }
        .highlight-card {
            background: var(--bg-card);
            border-radius: var(--radius-md);
            padding: 32px 24px 28px;
            border: 1px solid var(--border-subtle);
            text-align: center;
            transition: all var(--transition-smooth);
            position: relative;
            box-shadow: var(--shadow-card);
        }
        .highlight-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-card-hover);
            border-color: rgba(6, 182, 212, 0.35);
        }
        .highlight-card-icon {
            width: 64px;
            height: 64px;
            border-radius: 50%;
            margin: 0 auto 18px;
            display: flex;
            align-items: center;
            justify-content: center;
            border: 2px solid var(--accent);
            font-size: 26px;
            color: var(--accent);
            box-shadow: 0 0 18px rgba(6, 182, 212, 0.2);
            transition: all var(--transition-smooth);
            background: var(--bg-card);
        }
        .highlight-card:hover .highlight-card-icon {
            box-shadow: 0 0 30px rgba(6, 182, 212, 0.45);
            border-color: var(--accent);
        }
        .highlight-card h3 {
            font: var(--font-h3);
            color: var(--text-primary);
            margin: 0 0 8px;
        }
        .highlight-card p {
            font: var(--font-body);
            font-size: 14px;
            line-height: 22px;
            color: var(--text-secondary);
            margin: 0;
        }

        /* ========== Cases 瀑布流 ========== */
        #cases {
            background: var(--bg-deep);
        }
        .cases-masonry {
            column-count: 3;
            column-gap: 24px;
        }
        .case-card {
            break-inside: avoid;
            margin-bottom: 24px;
            background: var(--bg-card);
            border-radius: var(--radius-md);
            overflow: hidden;
            border: 1px solid var(--border-subtle);
            transition: all var(--transition-smooth);
            box-shadow: var(--shadow-card);
            cursor: default;
        }
        .case-card:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-card-hover);
            border-color: rgba(6, 182, 212, 0.35);
        }
        .case-card-img {
            width: 100%;
            display: block;
            object-fit: cover;
            aspect-ratio: 16/10;
            background: var(--bg-darker);
        }
        .case-card-body {
            padding: 18px 20px 20px;
        }
        .case-card-tags {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
            margin-bottom: 8px;
        }
        .case-tag {
            font: var(--font-small);
            font-weight: 500;
            background: var(--accent-subtle);
            color: var(--accent);
            padding: 3px 12px;
            border-radius: var(--radius-full);
            letter-spacing: 0.03em;
        }
        .case-card h4 {
            font: var(--font-h4);
            color: var(--text-primary);
            margin: 0 0 6px;
            font-size: 18px;
            line-height: 26px;
        }
        .case-card .case-year {
            font: var(--font-small);
            color: var(--text-muted);
            letter-spacing: 0.04em;
        }

        /* ========== Solutions ========== */
        #solutions {
            background: var(--bg-darker);
            position: relative;
        }
        #solutions::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 1px;
            background: linear-gradient(90deg, transparent, var(--border-primary), transparent);
        }
        .solutions-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 20px;
        }
        .solution-card {
            background: var(--bg-card);
            border-radius: var(--radius-md);
            padding: 30px 22px 26px;
            border: 1px solid var(--border-subtle);
            text-align: center;
            transition: all var(--transition-smooth);
            position: relative;
            box-shadow: var(--shadow-card);
        }
        .solution-card:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-card-hover);
            border-color: rgba(6, 182, 212, 0.3);
        }
        .solution-card.featured {
            border-color: var(--primary);
            box-shadow: 0 4px 28px rgba(139, 92, 246, 0.2);
            transform: translateY(-6px);
        }
        .solution-card.featured:hover {
            transform: translateY(-8px);
            box-shadow: 0 8px 44px rgba(139, 92, 246, 0.35);
        }
        .solution-badge {
            position: absolute;
            top: -13px;
            left: 50%;
            transform: translateX(-50%);
            background: var(--primary);
            color: #fff;
            font-size: 12px;
            font-weight: 700;
            padding: 5px 16px;
            border-radius: var(--radius-full);
            letter-spacing: 0.05em;
            white-space: nowrap;
            box-shadow: 0 0 16px var(--primary-glow);
        }
        .solution-card h3 {
            font: var(--font-h3);
            color: var(--text-primary);
            margin: 0 0 6px;
            font-size: 20px;
            line-height: 28px;
        }
        .solution-price {
            font: var(--font-mono);
            font-size: 15px;
            font-weight: 600;
            color: var(--accent);
            margin-bottom: 18px;
            letter-spacing: 0.02em;
        }
        .solution-features {
            list-style: none;
            text-align: left;
            margin: 0 0 20px;
            padding: 0;
        }
        .solution-features li {
            padding: 7px 0;
            font-size: 14px;
            line-height: 22px;
            color: var(--text-secondary);
            display: flex;
            align-items: center;
            gap: 10px;
            border-bottom: 1px solid var(--border-subtle);
        }
        .solution-features li .check {
            color: var(--success);
            font-weight: 700;
            flex-shrink: 0;
        }
        .solution-features li .cross {
            color: var(--text-muted);
            flex-shrink: 0;
        }
        .solution-card .btn-outline {
            width: 100%;
            justify-content: center;
            padding: 12px 20px;
            font-size: 14px;
        }
        .solution-card.featured .btn-outline {
            background: var(--primary);
            color: #fff;
            border-color: var(--primary);
        }
        .solution-card.featured .btn-outline:hover {
            background: var(--primary-light);
            box-shadow: var(--shadow-btn-primary);
        }
        .solutions-scroll-hint {
            display: none;
            text-align: center;
            font-size: 12px;
            color: var(--text-muted);
            margin-top: 14px;
            letter-spacing: 0.03em;
        }

        /* ========== FAQ ========== */
        #faq {
            background: var(--bg-deep);
        }
        .faq-list {
            max-width: 800px;
            margin: 0 auto;
        }
        .faq-item {
            border-bottom: 1px solid var(--border-subtle);
        }
        .faq-question {
            width: 100%;
            text-align: left;
            padding: 20px 0;
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 16px;
            cursor: pointer;
            font: var(--font-h4);
            font-size: 17px;
            line-height: 26px;
            color: var(--text-primary);
            transition: color var(--transition-fast);
            background: none;
            border: none;
        }
        .faq-question:hover {
            color: var(--accent);
        }
        .faq-arrow {
            flex-shrink: 0;
            width: 28px;
            height: 28px;
            border-radius: 50%;
            border: 1px solid var(--border-light);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 14px;
            color: var(--primary);
            transition: all var(--transition-smooth);
        }
        .faq-item.active .faq-arrow {
            transform: rotate(180deg);
            background: var(--primary);
            color: #fff;
            border-color: var(--primary);
            box-shadow: 0 0 12px var(--primary-glow);
        }
        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height var(--transition-slow), padding var(--transition-smooth);
        }
        .faq-item.active .faq-answer {
            max-height: 300px;
        }
        .faq-answer-inner {
            padding: 0 0 20px;
            font: var(--font-body);
            font-size: 15px;
            line-height: 24px;
            color: var(--text-secondary);
        }

        /* ========== Contact ========== */
        #contact {
            background: var(--bg-darker);
            position: relative;
        }
        #contact::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 1px;
            background: linear-gradient(90deg, transparent, var(--border-primary), transparent);
        }
        .contact-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 48px;
            align-items: start;
        }
        .contact-form-wrap {
            background: var(--bg-card);
            border-radius: var(--radius-md);
            padding: 36px 30px;
            border: 1px solid var(--border-subtle);
        }
        .contact-form-wrap h3 {
            font: var(--font-h3);
            color: var(--text-primary);
            margin: 0 0 22px;
            font-size: 20px;
        }
        .form-group {
            margin-bottom: 16px;
        }
        .form-group label {
            display: block;
            font-size: 14px;
            font-weight: 600;
            color: var(--text-secondary);
            margin-bottom: 6px;
            letter-spacing: 0.02em;
        }
        .form-input {
            width: 100%;
            padding: 13px 16px;
            background: var(--bg-darker);
            border: 1px solid var(--border-light);
            border-radius: var(--radius-sm);
            font-size: 15px;
            color: var(--text-primary);
            transition: all var(--transition-fast);
        }
        .form-input:focus {
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.15);
            outline: none;
        }
        .form-input::placeholder {
            color: var(--text-muted);
        }
        textarea.form-input {
            resize: vertical;
            min-height: 100px;
        }
        .btn-submit {
            width: 100%;
            padding: 14px 28px;
            border-radius: var(--radius-sm);
            font: var(--font-btn);
            letter-spacing: var(--letter-spacing-btn);
            background: var(--primary);
            color: #fff;
            transition: all var(--transition-smooth);
            cursor: pointer;
            border: 2px solid transparent;
            margin-top: 6px;
        }
        .btn-submit:hover {
            background: var(--primary-light);
            box-shadow: var(--shadow-btn-primary);
        }
        .btn-submit:focus-visible {
            outline: 3px solid var(--accent);
            outline-offset: 3px;
            border-radius: var(--radius-sm);
        }
        .contact-info {
            display: flex;
            flex-direction: column;
            gap: 24px;
        }
        .contact-info h3 {
            font: var(--font-h3);
            color: var(--text-primary);
            margin: 0;
            font-size: 20px;
        }
        .contact-info-item {
            display: flex;
            align-items: flex-start;
            gap: 14px;
        }
        .contact-info-icon {
            width: 44px;
            height: 44px;
            border-radius: 50%;
            background: var(--primary-subtle);
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            color: var(--primary);
            font-size: 18px;
            border: 1px solid var(--border-primary);
        }
        .contact-info-text {
            font: var(--font-body);
            font-size: 15px;
            line-height: 24px;
            color: var(--text-secondary);
        }
        .contact-info-text strong {
            display: block;
            color: var(--text-primary);
            font-weight: 600;
            margin-bottom: 2px;
        }
        .contact-social {
            display: flex;
            gap: 12px;
            margin-top: 6px;
        }
        .contact-social a {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--text-secondary);
            font-size: 18px;
            transition: all var(--transition-fast);
        }
        .contact-social a:hover {
            background: var(--primary);
            color: #fff;
            border-color: var(--primary);
            box-shadow: 0 0 16px var(--primary-glow);
        }

        /* ========== Footer ========== */
        .site-footer {
            background: var(--bg-darker);
            border-top: 1px solid var(--border-subtle);
            padding: 56px 0 28px;
        }
        .footer-grid {
            display: grid;
            grid-template-columns: 1.5fr 1fr 1fr 1fr;
            gap: 36px;
            margin-bottom: 36px;
        }
        .footer-col h4 {
            font: var(--font-h4);
            font-size: 16px;
            color: var(--text-primary);
            margin: 0 0 14px;
            letter-spacing: 0.02em;
        }
        .footer-col p {
            font: var(--font-small);
            color: var(--text-muted);
            line-height: 22px;
            margin: 0;
        }
        .footer-col ul {
            list-style: none;
            padding: 0;
            margin: 0;
        }
        .footer-col ul li {
            margin-bottom: 8px;
        }
        .footer-col ul li a {
            font: var(--font-small);
            color: var(--text-muted);
            transition: color var(--transition-fast);
        }
        .footer-col ul li a:hover {
            color: var(--accent);
        }
        .footer-social {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
        }
        .footer-social a {
            width: 36px;
            height: 36px;
            border-radius: 50%;
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--text-muted);
            font-size: 16px;
            transition: all var(--transition-fast);
        }
        .footer-social a:hover {
            background: var(--accent);
            color: var(--bg-deep);
            border-color: var(--accent);
            box-shadow: 0 0 14px var(--accent-glow);
        }
        .footer-bottom {
            border-top: 1px solid var(--border-subtle);
            padding-top: 20px;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            align-items: center;
            gap: 12px;
            font: var(--font-small);
            color: var(--text-muted);
        }
        .footer-bottom-links {
            display: flex;
            gap: 18px;
            flex-wrap: wrap;
        }
        .footer-bottom-links a {
            color: var(--text-muted);
            font-size: 13px;
        }
        .footer-bottom-links a:hover {
            color: var(--accent);
        }
        .back-to-top {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            color: var(--accent);
            font-weight: 600;
            font-size: 13px;
            cursor: pointer;
            transition: color var(--transition-fast);
        }
        .back-to-top:hover {
            color: var(--primary);
        }

        /* ========== 响应式 ========== */
        @media (max-width: 1024px) {
            :root {
                --section-py: 72px;
            }
            .hero .container {
                grid-template-columns: 1fr;
                gap: 32px;
                text-align: center;
            }
            .hero-content {
                align-items: center;
                order: 1;
            }
            .hero-visual {
                order: 0;
                max-width: 380px;
                margin: 0 auto;
            }
            .hero-visual-frame {
                aspect-ratio: 1/1;
            }
            .hero h1 {
                font-size: 38px;
                line-height: 46px;
            }
            .hero h2 {
                font-size: 17px;
                line-height: 26px;
            }
            .highlights-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            .cases-masonry {
                column-count: 2;
            }
            .solutions-grid {
                grid-template-columns: repeat(2, 1fr);
                gap: 20px;
            }
            .solution-card.featured {
                transform: translateY(0);
            }
            .solution-card.featured:hover {
                transform: translateY(-3px);
            }
            .footer-grid {
                grid-template-columns: 1fr 1fr;
                gap: 28px;
            }
            .contact-grid {
                grid-template-columns: 1fr;
                gap: 32px;
            }
        }

        @media (max-width: 768px) {
            :root {
                --nav-height: var(--nav-height-mobile);
                --section-py: var(--section-py-mobile);
                --container-px: 16px;
            }
            html {
                scroll-padding-top: var(--nav-height-mobile);
            }
            .nav-links {
                display: none;
            }
            .nav-cta .btn-nav {
                display: none;
            }
            .nav-hamburger {
                display: flex;
            }
            .nav-mobile-overlay {
                display: flex;
            }
            .hero {
                min-height: auto;
                padding: 100px 0 50px;
            }
            .hero h1 {
                font-size: 30px;
                line-height: 38px;
            }
            .hero h2 {
                font-size: 15px;
                line-height: 23px;
            }
            .hero-buttons {
                flex-direction: column;
                width: 100%;
                gap: 10px;
            }
            .hero-buttons .btn-primary,
            .hero-buttons .btn-outline {
                width: 100%;
                justify-content: center;
            }
            .hero-visual {
                max-width: 260px;
            }
            .highlights-grid {
                grid-template-columns: 1fr;
                gap: 16px;
            }
            .cases-masonry {
                column-count: 1;
            }
            .solutions-grid {
                grid-template-columns: repeat(4, minmax(240px, 1fr));
                overflow-x: auto;
                gap: 14px;
                padding-bottom: 8px;
                -webkit-overflow-scrolling: touch;
                scroll-snap-type: x proximity;
            }
            .solution-card {
                scroll-snap-align: start;
                min-width: 240px;
            }
            .solution-card.featured {
                transform: translateY(0);
            }
            .solutions-scroll-hint {
                display: block;
            }
            .section-header {
                margin-bottom: 36px;
            }
            .section-header h2 {
                font-size: 26px;
                line-height: 34px;
            }
            .contact-form-wrap {
                padding: 24px 18px;
            }
            .footer-grid {
                grid-template-columns: 1fr;
                gap: 24px;
            }
            .footer-bottom {
                flex-direction: column;
                text-align: center;
            }
            .faq-question {
                font-size: 15px;
                line-height: 23px;
            }
        }

        @media (max-width: 520px) {
            .hero h1 {
                font-size: 26px;
                line-height: 34px;
            }
            .hero h2 {
                font-size: 14px;
                line-height: 21px;
            }
            .hero-visual {
                max-width: 200px;
            }
            .btn-primary,
            .btn-outline,
            .btn-accent {
                padding: 12px 22px;
                font-size: 14px;
            }
            .highlight-card {
                padding: 24px 16px 20px;
            }
            .highlight-card h3 {
                font-size: 18px;
                line-height: 26px;
            }
            .case-card h4 {
                font-size: 16px;
                line-height: 23px;
            }
            .solution-card {
                padding: 22px 16px 20px;
                min-width: 220px;
            }
            .solution-card h3 {
                font-size: 17px;
                line-height: 24px;
            }
            .footer-grid {
                gap: 20px;
            }
        }