:root {
            --rfq3-primary: #f05133;
            --rfq3-primary-dark: #d43f21;
            --rfq3-bg-dark: #1a1c1e;
            --rfq3-bg-light: #f8fafc;
            --rfq3-text-main: #2d3436;
            --rfq3-text-muted: #636e72;
            --rfq3-accent-blue: #0984e3;
            --rfq3-border: #e2e8f0;
            --rfq3-radius: 12px;
            --rfq3-shadow: 0 10px 30px rgba(0,0,0,0.08);
            --rfq3-container-width: 1100px;
        }

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

        body {
            font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
            color: var(--rfq3-text-main);
            background-color: var(--rfq3-bg-light);
            line-height: 1.8;
            overflow-x: hidden;
            word-break: break-word;
        }

        /* Navigation */
        .rfq3-header {
            position: fixed;
            top: 0;
            width: 100%;
            background: rgba(255, 255, 255, 0.9);
            backdrop-filter: blur(10px);
            z-index: 1000;
            border-bottom: 1px solid var(--rfq3-border);
            box-shadow: 0 2px 10px rgba(0,0,0,0.05);
        }

        .rfq3-nav-container {
            max-width: var(--rfq3-container-width);
            margin: 0 auto;
            padding: 0 24px;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            align-items: center;
            height: 80px;
        }

        .rfq3-logo {
            flex: 0 0 auto;
            min-width: 0;
        }

        .rfq3-logo img {
            height: 40px;
            width: auto;
            display: block;
        }

        .rfq3-menu {
            display: flex;
            flex-wrap: wrap;
            list-style: none;
            gap: 16px;
            min-width: 0;
        }

        .rfq3-menu li {
            min-width: 0;
        }

        .rfq3-menu a {
            text-decoration: none;
            color: var(--rfq3-text-main);
            font-size: 0.95rem;
            font-weight: 500;
            padding: 8px 4px;
            transition: color 0.3s;
            position: relative;
        }

        .rfq3-menu a:hover, .rfq3-menu a.active {
            color: var(--rfq3-primary);
        }

        .rfq3-menu a.active::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 100%;
            height: 2px;
            background: var(--rfq3-primary);
        }

        /* Hero Tutorial Section */
        .rfq3-hero {
            padding-top: 140px;
            padding-bottom: 80px;
            background: linear-gradient(135deg, #fff 0%, #f1f2f6 100%);
            position: relative;
            overflow: hidden;
        }

        .rfq3-hero-inner {
            max-width: var(--rfq3-container-width);
            margin: 0 auto;
            padding: 0 24px;
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 48px;
        }

        .rfq3-hero-content {
            flex: 1 1 500px;
            min-width: 0;
        }

        .rfq3-hero-title {
            font-size: clamp(2rem, 4vw + 0.5rem, 3.5rem);
            line-height: 1.2;
            font-weight: 800;
            color: var(--rfq3-bg-dark);
            margin-bottom: 24px;
            word-break: keep-all;
        }

        .rfq3-hero-subtitle {
            font-size: clamp(1.1rem, 1.5vw + 0.5rem, 1.4rem);
            color: var(--rfq3-text-muted);
            margin-bottom: 32px;
            border-left: 4px solid var(--rfq3-primary);
            padding-left: 20px;
        }

        .rfq3-hero-visual {
            flex: 1 1 400px;
            min-width: 0;
            display: flex;
            justify-content: center;
            position: relative;
        }

        .rfq3-diff-card {
            background: #fff;
            padding: 24px;
            border-radius: var(--rfq3-radius);
            box-shadow: var(--rfq3-shadow);
            width: 100%;
            max-width: 500px;
            border: 1px solid var(--rfq3-border);
            transform: rotate(-2deg);
            transition: transform 0.4s;
        }

        .rfq3-diff-card:hover {
            transform: rotate(0deg) translateY(-5px);
        }

        .rfq3-diff-line {
            height: 10px;
            margin-bottom: 12px;
            border-radius: 4px;
            background: #eee;
        }

        .rfq3-diff-line.removed { background: #ffeef0; border-left: 4px solid #f85149; }
        .rfq3-diff-line.added { background: #e6ffec; border-left: 4px solid #3fb950; }

        /* Tutorial Main Content */
        .rfq3-tutorial-section {
            padding: 80px 0;
        }

        .rfq3-container {
            max-width: var(--rfq3-container-width);
            margin: 0 auto;
            padding: 0 24px;
        }

        .rfq3-section-head {
            text-align: center;
            margin-bottom: 64px;
        }

        .rfq3-section-tag {
            display: inline-block;
            background: rgba(240, 81, 51, 0.1);
            color: var(--rfq3-primary);
            padding: 4px 16px;
            border-radius: 20px;
            font-weight: 600;
            font-size: 0.85rem;
            margin-bottom: 16px;
        }

        .rfq3-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
            gap: 32px;
        }

        .rfq3-card {
            background: #fff;
            padding: 40px;
            border-radius: var(--rfq3-radius);
            border: 1px solid var(--rfq3-border);
            transition: all 0.3s ease;
            display: flex;
            flex-direction: column;
            gap: 20px;
        }

        .rfq3-card:hover {
            box-shadow: var(--rfq3-shadow);
            border-color: var(--rfq3-primary);
        }

        .rfq3-card-icon {
            font-size: 2.5rem;
            color: var(--rfq3-primary);
        }

        .rfq3-card-title {
            font-size: 1.5rem;
            font-weight: 700;
        }

        .rfq3-card-desc {
            color: var(--rfq3-text-muted);
            font-size: 1rem;
        }

        /* Feature Detailed Display */
        .rfq3-feature-row {
            display: flex;
            flex-wrap: wrap;
            gap: 64px;
            align-items: center;
            margin-bottom: 96px;
        }

        .rfq3-feature-row:nth-child(even) {
            flex-direction: row-reverse;
        }

        .rfq3-feature-text {
            flex: 1 1 400px;
            min-width: 0;
        }

        .rfq3-feature-media {
            flex: 1 1 400px;
            min-width: 0;
            background: var(--rfq3-bg-dark);
            border-radius: 16px;
            padding: 20px;
            color: #fff;
            font-family: monospace;
            box-shadow: 0 20px 40px rgba(0,0,0,0.2);
        }

        .rfq3-feature-title {
            font-size: 2rem;
            margin-bottom: 20px;
            color: var(--rfq3-bg-dark);
        }

        .rfq3-feature-list {
            list-style: none;
        }

        .rfq3-feature-list li {
            margin-bottom: 12px;
            padding-left: 28px;
            position: relative;
        }

        .rfq3-feature-list li::before {
            content: "✓";
            position: absolute;
            left: 0;
            color: var(--rfq3-primary);
            font-weight: bold;
        }

        /* Footer */
        .rfq3-footer {
            background: var(--rfq3-bg-dark);
            color: #fff;
            padding: 80px 0 40px;
        }

        .rfq3-footer-inner {
            max-width: var(--rfq3-container-width);
            margin: 0 auto;
            padding: 0 24px;
            display: flex;
            flex-wrap: wrap;
            gap: 48px;
            justify-content: space-between;
        }

        .rfq3-footer-brand {
            flex: 1 1 300px;
            min-width: 0;
        }

        .rfq3-footer-logo-text {
            font-size: 1.8rem;
            font-weight: 800;
            margin-bottom: 16px;
            letter-spacing: -1px;
        }

        .rfq3-footer-links {
            flex: 1 1 600px;
            min-width: 0;
            display: flex;
            flex-wrap: wrap;
            gap: 40px;
        }

        .rfq3-footer-col {
            flex: 1 1 150px;
            min-width: 0;
        }

        .rfq3-footer-col h4 {
            margin-bottom: 24px;
            font-size: 1.1rem;
            color: #fff;
        }

        .rfq3-footer-col ul {
            list-style: none;
        }

        .rfq3-footer-col a {
            color: #a0aec0;
            text-decoration: none;
            display: block;
            margin-bottom: 12px;
            transition: color 0.3s;
        }

        .rfq3-footer-col a:hover {
            color: var(--rfq3-primary);
        }

        .rfq3-copyright {
            margin-top: 64px;
            padding-top: 32px;
            border-top: 1px solid rgba(255,255,255,0.1);
            text-align: center;
            color: #718096;
            font-size: 0.9rem;
        }

        /* Responsive Breakpoints */
        @media (max-width: 768px) {
            .rfq3-nav-container {
                height: auto;
                padding: 16px 24px;
            }
            .rfq3-menu {
                margin-top: 16px;
                gap: 12px;
            }
            .rfq3-hero {
                padding-top: 120px;
            }
            .rfq3-feature-row {
                gap: 32px;
            }
        }

        /* Utility */
        .rfq3-code-block {
            background: #2d3436;
            color: #fab1a0;
            padding: 2px 6px;
            border-radius: 4px;
            font-size: 0.9em;
        }