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

        body {
            font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Helvetica, sans-serif;
            background-color: #ffffff;
            color: #111111;
            line-height: 1.5;
            scroll-behavior: smooth;
        }

        .container {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 24px;
        }

        /* header */
        .header {
            background-color: #ffffff;
            border-bottom: 1px solid #e5e7eb;
            position: sticky;
            top: 0;
            z-index: 50;
        }

        .nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            padding: 18px 0;
        }

        .logo {
            font-size: 1.8rem;
            font-weight: 700;
            letter-spacing: -0.02em;
            background: linear-gradient(135deg, #25D366, #128C7E);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            text-decoration: none;
        }

        .nav-links {
            display: flex;
            gap: 32px;
            align-items: center;
            list-style: none;
        }

        .nav-links a {
            text-decoration: none;
            font-weight: 500;
            color: #1f2937;
            transition: color 0.2s;
            font-size: 1rem;
        }

        .nav-links a:hover {
            color: #25D366;
        }

        .nav-links .active {
            color: #128C7E;
            font-weight: 600;
        }

        .btn-outline {
            border: 1px solid #25D366;
            background: transparent;
            padding: 8px 20px;
            border-radius: 40px;
            font-weight: 600;
            color: #128C7E;
            transition: all 0.2s;
            text-decoration: none;
            cursor: pointer;
        }

        .btn-outline:hover {
            background: #25D36610;
            border-color: #128C7E;
        }

        /* button */
        .btn-primary {
            display: inline-block;
            background-color: #25D366;
            color: white;
            font-weight: 600;
            padding: 12px 32px;
            border-radius: 40px;
            text-decoration: none;
            transition: background 0.2s, transform 0.1s;
            border: none;
            font-size: 1rem;
            cursor: pointer;
        }

        .btn-primary:hover {
            background-color: #128C7E;
        }

        /* hero */
        .hero {
            padding: 80px 0 64px;
            background: linear-gradient(145deg, #f9fafb 0%, #ffffff 100%);
        }

        .hero-grid {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 48px;
        }

        .hero-content {
            flex: 1;
        }

        .hero-content h1 {
            font-size: 3.3rem;
            font-weight: 800;
            line-height: 1.2;
            letter-spacing: -0.02em;
            background: linear-gradient(135deg, #1f2b3c, #075e54);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            margin-bottom: 20px;
        }

        .hero-content p {
            font-size: 1.2rem;
            color: #374151;
            max-width: 540px;
            margin-bottom: 32px;
        }

        .hero-badge {
            background: #e9f9ef;
            display: inline-block;
            padding: 6px 14px;
            border-radius: 30px;
            font-size: 0.85rem;
            font-weight: 500;
            color: #075e54;
            margin-bottom: 24px;
        }

        .hero-image {
            flex: 1;
            text-align: center;
        }

        .hero-image svg {
            max-width: 100%;
            height: auto;
        }

        /* stats row */
        .stats-row {
            display: flex;
            gap: 24px;
            flex-wrap: wrap;
            margin-top: 16px;
        }

        .stat-item {
            background: #f0fdf6;
            border-radius: 16px;
            padding: 16px 20px;
            text-align: center;
            min-width: 100px;
            flex: 1;
            border: 1px solid #d4f5e2;
        }

        .stat-num {
            font-size: 1.8rem;
            font-weight: 700;
            color: #128C7E;
            letter-spacing: -0.01em;
        }

        .stat-label {
            font-size: 0.8rem;
            color: #4b5563;
            margin-top: 2px;
        }

        /* features section */
        .features {
            padding: 80px 0;
            background: #ffffff;
        }

        .section-title {
            text-align: center;
            font-size: 2.2rem;
            font-weight: 700;
            margin-bottom: 16px;
        }

        .section-desc {
            text-align: center;
            color: #4b5563;
            max-width: 640px;
            margin: 0 auto 56px;
            font-size: 1.1rem;
        }

        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: 40px;
        }

        .feature-card {
            background: #f9fafb;
            border-radius: 32px;
            padding: 32px 24px;
            text-align: center;
            transition: all 0.25s;
            border: 1px solid #edf2f7;
        }

        .feature-card:hover {
            transform: translateY(-6px);
            box-shadow: 0 20px 30px -12px rgba(0, 0, 0, 0.08);
            border-color: #cbf0da;
        }

        .feature-icon {
            font-size: 2.8rem;
            margin-bottom: 20px;
        }

        .feature-card h3 {
            font-size: 1.5rem;
            margin-bottom: 12px;
            font-weight: 600;
        }

        .feature-card p {
            color: #4b5563;
        }

        /* highlight strip */
        .highlight-strip {
            background: #f9fafb;
            border-radius: 24px;
            padding: 40px 36px;
            margin: 0 0 80px;
            display: flex;
            flex-wrap: wrap;
            gap: 28px;
            align-items: center;
            justify-content: center;
            border: 1px solid #eef2f6;
        }

        .highlight-item {
            display: flex;
            align-items: center;
            gap: 12px;
            font-weight: 600;
            color: #1f2b3c;
            font-size: 1rem;
        }

        .highlight-dot {
            width: 10px;
            height: 10px;
            border-radius: 50%;
            background: #25D366;
            flex-shrink: 0;
        }

        /* how-to section */
        .how-to {
            padding: 0 0 80px;
        }

        .steps-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 32px;
            counter-reset: step;
        }

        .step-card {
            background: #ffffff;
            border: 2px solid #eef2f6;
            border-radius: 24px;
            padding: 36px 24px 28px;
            text-align: center;
            position: relative;
            transition: all 0.2s;
            counter-increment: step;
        }

        .step-card::before {
            content: counter(step);
            position: absolute;
            top: -18px;
            left: 50%;
            transform: translateX(-50%);
            width: 36px;
            height: 36px;
            border-radius: 50%;
            background: #25D366;
            color: #fff;
            font-weight: 700;
            font-size: 1rem;
            display: flex;
            align-items: center;
            justify-content: center;
            line-height: 1;
        }

        .step-card:hover {
            border-color: #25D366;
            box-shadow: 0 8px 24px -8px rgba(37, 211, 102, 0.2);
        }

        .step-card h4 {
            font-size: 1.2rem;
            margin: 8px 0 8px;
            font-weight: 600;
        }

        .step-card p {
            color: #4b5563;
            font-size: 0.95rem;
        }

        /* resource hub */
        .resource-hub {
            padding: 0 0 80px;
        }

        .resource-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: 28px;
        }

        .resource-card {
            border-radius: 28px;
            padding: 36px 28px;
            text-decoration: none;
            transition: all 0.25s;
            border: 2px solid transparent;
            position: relative;
            overflow: hidden;
        }

        .resource-card.res-guide {
            background: #f0f9ff;
            border-color: #dbeafe;
        }

        .resource-card.res-security {
            background: #fffdf5;
            border-color: #fef3c7;
        }

        .resource-card.res-download {
            background: #f5fdf7;
            border-color: #d1fae5;
        }

        .resource-card.res-scenarios {
            background: #fdf7ff;
            border-color: #ede9fe;
        }

        .resource-card:hover {
            transform: translateY(-4px);
            box-shadow: 0 16px 32px -10px rgba(0, 0, 0, 0.1);
        }

        .resource-card .res-icon {
            font-size: 2.4rem;
            margin-bottom: 14px;
        }

        .resource-card h3 {
            font-size: 1.3rem;
            font-weight: 700;
            margin-bottom: 8px;
            color: #1f2b3c;
        }

        .resource-card p {
            color: #4b5563;
            font-size: 0.95rem;
            line-height: 1.6;
        }

        .resource-card .res-tag {
            display: inline-block;
            margin-top: 14px;
            padding: 5px 14px;
            border-radius: 20px;
            font-size: 0.78rem;
            font-weight: 600;
        }

        .res-guide .res-tag {
            background: #dbeafe;
            color: #1e40af;
        }
        .res-security .res-tag {
            background: #fef3c7;
            color: #92400e;
        }
        .res-download .res-tag {
            background: #d1fae5;
            color: #065f46;
        }
        .res-scenarios .res-tag {
            background: #ede9fe;
            color: #5b21b6;
        }

        /* cta 下载区 */
        .cta-section {
            background: linear-gradient(120deg, #eef9f2, #ffffff);
            border-radius: 48px;
            margin: 32px 0 80px;
            padding: 64px 48px;
            text-align: center;
        }

        .cta-section h2 {
            font-size: 2rem;
            font-weight: 700;
            margin-bottom: 16px;
        }

        .cta-buttons {
            margin-top: 32px;
            display: flex;
            gap: 20px;
            justify-content: center;
            flex-wrap: wrap;
        }

        .btn-secondary {
            background: white;
            border: 1px solid #cfdde6;
            padding: 12px 28px;
            border-radius: 40px;
            font-weight: 600;
            text-decoration: none;
            color: #1f2a3e;
            transition: 0.2s;
            cursor: pointer;
        }

        .btn-secondary:hover {
            border-color: #25D366;
            background: #f0fdf4;
        }

        /* faq section */
        .faq-section {
            padding: 0 0 80px;
        }

        .faq-list {
            max-width: 800px;
            margin: 0 auto;
        }

        .faq-list details {
            background: #f9fafb;
            border-radius: 16px;
            padding: 20px 28px;
            margin-bottom: 12px;
            border: 1px solid #edf2f7;
            cursor: pointer;
            transition: all 0.2s;
        }

        .faq-list details:hover {
            border-color: #cbf0da;
            background: #fdfdfd;
        }

        .faq-list summary {
            font-weight: 600;
            font-size: 1.05rem;
            color: #1f2b3c;
            list-style: none;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .faq-list summary::-webkit-details-marker {
            display: none;
        }

        .faq-list summary::after {
            content: '+';
            font-size: 1.4rem;
            color: #25D366;
            font-weight: 700;
            transition: transform 0.2s;
        }

        .faq-list details[open] summary::after {
            content: '−';
            color: #128C7E;
        }

        .faq-list .faq-answer {
            margin-top: 14px;
            color: #4b5563;
            line-height: 1.7;
            padding-top: 12px;
            border-top: 1px solid #eef2f6;
        }

        /* footer */
        .footer {
            border-top: 1px solid #eaeef3;
            padding: 48px 0 32px;
            background: #fafcff;
        }

        .footer-grid {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            gap: 32px;
            margin-bottom: 40px;
        }

        .footer-col {
            min-width: 140px;
        }

        .footer-col h4 {
            font-weight: 600;
            margin-bottom: 18px;
            color: #111827;
        }

        .footer-col ul {
            list-style: none;
        }

        .footer-col li {
            margin-bottom: 12px;
        }

        .footer-col a {
            text-decoration: none;
            color: #4b5563;
            font-size: 0.9rem;
        }

        .footer-col a:hover {
            color: #128C7E;
        }

        .copyright {
            text-align: center;
            padding-top: 28px;
            border-top: 1px solid #e5e7eb;
            font-size: 0.8rem;
            color: #6c757d;
        }

        /* scenarios tag cloud */
        .tag-cloud {
            display: flex;
            flex-wrap: wrap;
            gap: 12px;
            justify-content: center;
            margin: 40px 0 0;
        }

        .tag-cloud a {
            background: #f9fafb;
            border: 1px solid #e5e7eb;
            padding: 8px 18px;
            border-radius: 24px;
            text-decoration: none;
            color: #374151;
            font-size: 0.9rem;
            transition: all 0.2s;
            white-space: nowrap;
        }

        .tag-cloud a:hover {
            background: #e9f9ef;
            border-color: #25D366;
            color: #075e54;
            font-weight: 500;
        }

        @media (max-width: 768px) {
            .nav {
                flex-direction: column;
                gap: 16px;
            }
            .nav-links {
                flex-wrap: wrap;
                justify-content: center;
                gap: 20px;
            }
            .hero-content h1 {
                font-size: 2.3rem;
            }
            .cta-section {
                padding: 40px 24px;
            }
            .hero-grid {
                flex-direction: column;
            }
            .stats-row {
                gap: 12px;
            }
            .stat-item {
                min-width: 70px;
                padding: 12px 14px;
            }
            .stat-num {
                font-size: 1.4rem;
            }
            .highlight-strip {
                padding: 28px 20px;
                gap: 16px;
            }
            .resource-grid {
                grid-template-columns: 1fr;
            }
            .steps-grid {
                grid-template-columns: 1fr 1fr;
            }
        }

        @media (max-width: 480px) {
            .steps-grid {
                grid-template-columns: 1fr;
            }
            .hero-content h1 {
                font-size: 1.8rem;
            }
            .section-title {
                font-size: 1.6rem;
            }
            .cta-buttons {
                flex-direction: column;
                align-items: center;
            }
        }