:root {
            --deep-blue: #0a1628;
            --navy: #111d33;
            --card-bg: #ffffff;
            --surface: #f8fafc;
            --surface-alt: #f1f5f9;
            --accent: #3b82f6;
            --accent-hover: #2563eb;
            --accent-light: #dbeafe;
            --accent-glow: rgba(59, 130, 246, 0.25);
            --teal: #06b6d4;
            --gradient-cta: linear-gradient(135deg, #3b82f6 0%, #06b6d4 100%);
            --gradient-cta-hover: linear-gradient(135deg, #2563eb 0%, #0891b2 100%);
            --text-primary: #0f172a;
            --text-secondary: #475569;
            --text-tertiary: #64748b;
            --text-inverse: #f8fafc;
            --border: #e2e8f0;
            --border-light: #f1f5f9;
            --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
            --shadow-md: 0 4px 16px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
            --shadow-lg: 0 12px 40px rgba(0,0,0,0.12), 0 4px 12px rgba(0,0,0,0.06);
            --shadow-xl: 0 24px 64px rgba(0,0,0,0.16), 0 8px 20px rgba(0,0,0,0.08);
            --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 8px 32px rgba(0,0,0,0.08);
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 20px;
            --radius-xl: 28px;
            --radius-full: 9999px;
            --section-gap: 80px;
            --content-max: 1100px;
            --ease-out: cubic-bezier(0.22, 0.61, 0.36, 1);
            --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
        }

        *,
        *::before,
        *::after { box-sizing: border-box; margin: 0; padding: 0; }
        html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; font-size: 16px; }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
            color: var(--text-primary);
            background-color: var(--surface);
            line-height: 1.6;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            overflow-x: hidden;
        }

        /* 导航栏 */
        .nav {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 1000;
            background: rgba(255,255,255,0.88);
            backdrop-filter: blur(16px);
            -webkit-backdrop-filter: blur(16px);
            border-bottom: 1px solid var(--border-light);
            transition: box-shadow 0.3s var(--ease-out);
            height: 60px;
            display: flex;
            align-items: center;
        }
        .nav.scrolled { box-shadow: var(--shadow-sm); }
        .nav-inner {
            max-width: var(--content-max);
            width: 100%;
            margin: 0 auto;
            padding: 0 24px;
            display: flex;
            align-items: center;
            justify-content: space-between;
        }
        .nav-brand {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            color: var(--text-primary);
            font-weight: 700;
            font-size: 1.25rem;
            letter-spacing: -0.01em;
        }
        .nav-brand-icon {
            width: 36px;
            height: 36px;
            border-radius: var(--radius-sm);
            background: var(--gradient-cta);
            display: flex;
            align-items: center;
            justify-content: center;
            color: #fff;
            font-weight: 800;
            font-size: 1.1rem;
            flex-shrink: 0;
        }
        .nav-links {
            display: flex;
            align-items: center;
            gap: 12px;
        }
        .nav-link {
            padding: 8px 18px;
            border-radius: var(--radius-full);
            font-weight: 600;
            font-size: 0.9rem;
            text-decoration: none;
            transition: all 0.25s var(--ease-out);
            white-space: nowrap;
            cursor: pointer;
            border: 1px solid transparent;
            background: transparent;
            color: var(--text-secondary);
        }
        .nav-link:hover {
            background: var(--accent-light);
            color: var(--accent);
        }
        .nav-cta {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            padding: 9px 20px;
            border-radius: var(--radius-full);
            background: var(--accent);
            color: #fff;
            text-decoration: none;
            font-weight: 600;
            font-size: 0.9rem;
            transition: all 0.25s var(--ease-out);
            white-space: nowrap;
            box-shadow: 0 2px 8px rgba(59,130,246,0.3);
        }
        .nav-cta:hover {
            background: var(--accent-hover);
            box-shadow: 0 4px 16px rgba(59,130,246,0.4);
            transform: translateY(-1px);
        }

        /* 全屏卡片区域通用样式 */
        .fullscreen-card {
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 100px 24px 60px;
            position: relative;
            overflow: hidden;
        }
        .fullscreen-card--dark {
            background-color: var(--deep-blue);
            background-image:
                radial-gradient(ellipse at 25% 15%, rgba(59,130,246,0.18) 0%, transparent 55%),
                radial-gradient(ellipse at 72% 78%, rgba(6,182,212,0.13) 0%, transparent 55%),
                radial-gradient(ellipse at 50% 50%, rgba(30,58,95,0.4) 0%, transparent 70%);
        }
        .fullscreen-card--light {
            background-color: #ffffff;
            background-image:
                radial-gradient(ellipse at 70% 20%, rgba(59,130,246,0.06) 0%, transparent 55%),
                radial-gradient(ellipse at 20% 80%, rgba(6,182,212,0.05) 0%, transparent 55%);
        }
        .fullscreen-card::before {
            content: '';
            position: absolute;
            inset: 0;
            opacity: 0.03;
            background-image:
                linear-gradient(rgba(255,255,255,0.5) 1px, transparent 1px),
                linear-gradient(90deg, rgba(255,255,255,0.5) 1px, transparent 1px);
            background-size: 48px 48px;
            pointer-events: none;
        }
        .hero-orb {
            position: absolute;
            border-radius: 50%;
            filter: blur(80px);
            pointer-events: none;
            opacity: 0.5;
        }
        .hero-orb--top { width:380px; height:380px; background:rgba(59,130,246,0.22); top:-120px; left:-80px; }
        .hero-orb--bottom { width:300px; height:300px; background:rgba(6,182,212,0.18); bottom:-100px; right:-60px; }

        .card {
            position: relative;
            z-index: 2;
            background: var(--card-bg);
            border-radius: var(--radius-xl);
            padding: clamp(32px, 5vw, 56px) clamp(24px, 6vw, 56px);
            max-width: 780px;
            width: 100%;
            box-shadow: var(--shadow-xl), 0 0 0 1px rgba(255,255,255,0.08) inset;
            text-align: center;
            animation: card-enter 0.7s var(--ease-out) both;
        }
        @keyframes card-enter {
            from { opacity: 0; transform: translateY(30px); }
            to { opacity: 1; transform: translateY(0); }
        }
        .card-badge {
            display: inline-block;
            padding: 5px 14px;
            border-radius: var(--radius-full);
            background: var(--accent-light);
            color: var(--accent);
            font-weight: 600;
            font-size: 1.2rem;
            letter-spacing: 0.03em;
            margin-bottom: 20px;
            text-transform: uppercase;
        }
        .card-icon {
            width: 64px;
            height: 64px;
            border-radius: var(--radius-lg);
            background: var(--gradient-cta);
            display: inline-flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 20px;
            box-shadow: 0 8px 24px rgba(59,130,246,0.3);
        }
        .card h2 {
            font-size: clamp(1.6rem, 3.5vw, 2.4rem);
            font-weight: 800;
            letter-spacing: -0.02em;
            color: var(--text-primary);
            margin-bottom: 10px;
            line-height: 1.25;
        }
        .card .subtitle {
            font-size: clamp(1rem, 1.8vw, 1.18rem);
            color: var(--text-secondary);
            margin-bottom: 28px;
            line-height: 1.5;
            max-width: 560px;
            margin-left: auto;
            margin-right: auto;
        }
        .value-list {
            list-style: none;
            display: flex;
            flex-direction: column;
            gap: 14px;
            margin-bottom: 32px;
            text-align: left;
            max-width: 480px;
            margin-left: auto;
            margin-right: auto;
        }
        .value-list li {
            display: flex;
            align-items: flex-start;
            gap: 12px;
            font-size: 0.95rem;
            color: var(--text-secondary);
            line-height: 1.4;
        }
        .value-icon {
            flex-shrink: 0;
            width: 22px;
            height: 22px;
            border-radius: 50%;
            background: #ecfdf5;
            color: #10b981;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 0.75rem;
            font-weight: 700;
            margin-top: 1px;
        }
        .actions {
            display: flex;
            flex-wrap: wrap;
            gap: 12px;
            justify-content: center;
        }
        .btn {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            padding: 13px 28px;
            border-radius: var(--radius-full);
            font-weight: 600;
            font-size: 0.95rem;
            text-decoration: none;
            cursor: pointer;
            border: none;
            transition: all 0.3s var(--ease-out);
            white-space: nowrap;
            letter-spacing: 0.01em;
        }
        .btn-primary {
            background: var(--gradient-cta);
            color: #fff;
            box-shadow: 0 4px 16px rgba(59,130,246,0.35);
            position: relative;
            overflow: hidden;
        }
        .btn-primary::after {
            content: '';
            position: absolute;
            inset: 0;
            background: linear-gradient(135deg, rgba(255,255,255,0.2) 0%, transparent 50%);
            pointer-events: none;
        }
        .btn-primary:hover {
            box-shadow: 0 8px 28px rgba(59,130,246,0.5);
            transform: translateY(-2px);
        }
        .btn-secondary {
            background: var(--surface-alt);
            color: var(--text-primary);
            border: 1px solid var(--border);
        }
        .btn-secondary:hover {
            background: #e8ecf1;
            border-color: #cbd5e1;
            transform: translateY(-2px);
            box-shadow: var(--shadow-md);
        }
        .btn-arrow {
            font-size: 0.85em;
            transition: transform 0.3s var(--ease-out);
        }
        .btn:hover .btn-arrow { transform: translateX(4px); }
        .btn-secondary:hover .btn-arrow { transform: translateY(4px); }

        /* 滚动提示 */
        .scroll-hint {
            position: absolute;
            bottom: 28px;
            left: 50%;
            transform: translateX(-50%);
            z-index: 3;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 6px;
            color: rgba(255,255,255,0.5);
            font-size: 0.75rem;
            animation: float 2.5s ease-in-out infinite;
            letter-spacing: 0.04em;
        }
        .scroll-hint span {
            display: block;
            width: 20px;
            height: 20px;
            border-right: 2px solid rgba(255,255,255,0.4);
            border-bottom: 2px solid rgba(255,255,255,0.4);
            transform: rotate(45deg);
        }
        @keyframes float {
            0%,100% { transform: translateX(-50%) translateY(0); }
            50% { transform: translateX(-50%) translateY(8px); }
        }

        /* 弹出提示层 */
        .toast-overlay {
            position: fixed;
            inset: 0;
            background: rgba(0,0,0,0.4);
            z-index: 2000;
            display: flex;
            align-items: center;
            justify-content: center;
            animation: fadeIn 0.25s ease-out;
        }
        .toast-box {
            background: #fff;
            border-radius: var(--radius-lg);
            padding: 32px 40px;
            text-align: center;
            box-shadow: var(--shadow-xl);
            max-width: 400px;
            width: 90%;
            animation: popIn 0.3s var(--ease-spring);
        }
        .toast-box p {
            font-size: 1.1rem;
            font-weight: 600;
            margin-bottom: 20px;
            color: var(--text-primary);
        }
        .toast-box button {
            padding: 10px 28px;
            background: var(--accent);
            color: #fff;
            border: none;
            border-radius: var(--radius-full);
            font-weight: 600;
            cursor: pointer;
            transition: background 0.2s;
        }
        .toast-box button:hover { background: var(--accent-hover); }

        @keyframes fadeIn { from { opacity:0; } to { opacity:1; } }
        @keyframes popIn {
            from { transform: scale(0.9); opacity:0; }
            to { transform: scale(1); opacity:1; }
        }

        /* FAQ等其他区域保留 */
        .features-section {
            padding: var(--section-gap) 24px;
            background: #fff;
        }
        .features-section .container { max-width: var(--content-max); margin:0 auto; }
        .section-label {
            display: inline-block;
            font-size: 0.8rem;
            font-weight: 700;
            letter-spacing: 0.06em;
            text-transform: uppercase;
            color: var(--accent);
            margin-bottom: 10px;
        }
        .section-title {
            font-size: clamp(1.5rem, 2.8vw, 2rem);
            font-weight: 800;
            letter-spacing: -0.02em;
            color: var(--text-primary);
            margin-bottom: 12px;
            line-height: 1.3;
        }
        .section-desc {
            font-size: 1.05rem;
            color: var(--text-secondary);
            max-width: 600px;
            margin-bottom: 40px;
            line-height: 1.6;
        }
        .pain-solution-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 20px;
            margin-bottom: 48px;
        }
        .ps-card {
            background: var(--surface);
            border-radius: var(--radius-lg);
            padding: 28px;
            border: 1px solid var(--border-light);
            transition: all 0.3s var(--ease-out);
        }
        .ps-card:hover { box-shadow: var(--shadow-lg); border-color: transparent; transform: translateY(-2px); }
        .ps-card-tag {
            display: inline-block;
            padding: 3px 10px;
            border-radius: var(--radius-full);
            font-size: 0.7rem;
            font-weight: 700;
            letter-spacing: 0.04em;
            text-transform: uppercase;
            margin-bottom: 12px;
        }
        .ps-card-tag--pain { background: #fef2f2; color: #dc2626; }
        .ps-card-tag--solve { background: #ecfdf5; color: #059669; }
        .ps-card h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 6px; color: var(--text-primary); }
        .ps-card p { font-size: 0.9rem; color: var(--text-tertiary); line-height: 1.5; }
        .feature-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: 16px;
            margin-bottom: 48px;
        }
        .feature-item {
            background: #fff;
            border-radius: var(--radius-md);
            padding: 22px 20px;
            border: 1px solid var(--border);
            transition: all 0.25s var(--ease-out);
        }
        .feature-item:hover { border-color: var(--accent); box-shadow: var(--shadow-md); }
        .feature-item-icon {
            width: 40px;
            height: 40px;
            border-radius: var(--radius-sm);
            background: var(--accent-light);
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 12px;
            font-size: 1.2rem;
        }
        .feature-item h4 { font-size: 0.95rem; font-weight: 700; margin-bottom: 4px; }
        .feature-item p { font-size: 0.82rem; color: var(--text-tertiary); line-height: 1.4; }
        .audience-tags {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
            margin-top: 10px;
        }
        .audience-tag {
            display: inline-block;
            padding: 8px 18px;
            border-radius: var(--radius-full);
            background: #f8fafc;
            border: 1px solid var(--border);
            font-size: 0.85rem;
            font-weight: 500;
            color: var(--text-secondary);
            transition: all 0.2s;
        }
        .audience-tag:hover { background: var(--accent-light); border-color: var(--accent); color: var(--accent); }

        .faq-section {
            padding: var(--section-gap) 24px;
            background: var(--surface);
        }
        .faq-section .container { max-width: 800px; margin:0 auto; }
        .faq-list { display: flex; flex-direction: column; gap: 10px; }
        .faq-item {
            background: #fff;
            border-radius: var(--radius-md);
            border: 1px solid var(--border-light);
            overflow: hidden;
            transition: all 0.25s;
        }
        .faq-item:hover { border-color: #dde4ef; box-shadow: var(--shadow-sm); }
        .faq-item summary {
            padding: 18px 22px;
            cursor: pointer;
            font-weight: 600;
            font-size: 0.95rem;
            color: var(--text-primary);
            list-style: none;
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 12px;
            user-select: none;
        }
        .faq-item summary::-webkit-details-marker { display: none; }
        .faq-item summary::marker { display: none; content:''; }
        .faq-item summary:hover { color: var(--accent); }
        .faq-chevron {
            flex-shrink: 0;
            width: 20px;
            height: 20px;
            border-radius: 50%;
            background: var(--surface-alt);
            display: flex;
            align-items: center;
            justify-content: center;
            transition: transform 0.35s var(--ease-spring);
            font-size: 0.65rem;
            color: var(--text-tertiary);
        }
        .faq-item[open] .faq-chevron {
            transform: rotate(180deg);
            background: var(--accent-light);
            color: var(--accent);
        }
        .faq-answer {
            padding: 0 22px 18px;
            font-size: 0.9rem;
            color: var(--text-secondary);
            line-height: 1.6;
            animation: faq-reveal 0.35s var(--ease-out);
        }
        @keyframes faq-reveal { from { opacity:0; transform: translateY(-8px); } to { opacity:1; transform: translateY(0); } }

        .footer {
            background: var(--deep-blue);
            color: rgba(255,255,255,0.7);
            padding: 40px 24px;
            text-align: center;
            font-size: 0.85rem;
            line-height: 1.8;
        }
        .footer-inner { max-width: var(--content-max); margin:0 auto; }
        .footer-brand { color: #fff; font-weight: 700; font-size: 1.05rem; margin-bottom: 8px; }
        .footer-links { display: flex; flex-wrap: wrap; gap: 16px; justify-content: center; margin-bottom: 12px; }
        .footer-links a { color: rgba(255,255,255,0.6); text-decoration: none; transition: color 0.2s; }
        .footer-links a:hover { color: #fff; }
        .footer-divider { width: 40px; height: 2px; background: rgba(255,255,255,0.2); margin: 16px auto; border-radius: 2px; }
        .footer-copy { color: rgba(255,255,255,0.4); font-size: 0.8rem; }

        .reveal {
            opacity: 0;
            transform: translateY(24px);
            transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
        }
        .reveal.visible { opacity: 1; transform: translateY(0); }

        @media (max-width: 768px) {
            .fullscreen-card { padding: 80px 16px 50px; }
            .card { padding: 28px 20px; border-radius: var(--radius-lg); }
            .card h2 { font-size: 1.5rem; }
            .btn { padding: 12px 22px; font-size: 0.9rem; width: 100%; justify-content: center; }
            .actions { flex-direction: column; }
            .pain-solution-grid { grid-template-columns: 1fr; }
            .feature-grid { grid-template-columns: 1fr 1fr; gap: 10px; }
            .feature-item { padding: 16px 14px; }
            .nav-links { gap: 6px; }
            .nav-link { padding: 6px 12px; font-size: 0.8rem; }
        }
        @media (max-width: 480px) {
            .feature-grid { grid-template-columns: 1fr; }
        }