:root {
            /* 背景色 */
            --bg-cold-ivory: #F6F7F9;
            --bg-warm-cream: #F9F7F4;
            --porcelain-white: #FFFFFF;
            --paper-cream: #FDFCF8;
            
            /* 强调色 */
            --accent-copper: #A67B5B;
            --accent-copper-hover: #B88B6B;
            --accent-gold: #D4AF37;
            --accent-warm: #C9A87C;
            
            /* 文字色 */
            --text-primary: #2D2D2D;
            --text-secondary: #6B6B6B;
            --text-tertiary: #9A9A9A;
            --ink-brown: #4A4036;
            
            /* 边框与阴影 */
            --border-copper-light: rgba(166, 123, 91, 0.15);
            --border-copper-medium: rgba(166, 123, 91, 0.3);
            --shadow-soft: 0 1px 3px rgba(0,0,0,0.02), 0 4px 12px rgba(0,0,0,0.04);
            --shadow-hover: 0 4px 12px rgba(0,0,0,0.06), 0 12px 24px rgba(166, 123, 91, 0.1);
            --shadow-magic: 0 8px 32px rgba(212, 175, 55, 0.15);
            
            /* 圆角 */
            --radius-porcelain: 8px;
            --radius-soft: 16px;
            
            /* 缓动函数 */
            --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);
        }

        /* ========================================
           Reset & Base
           ======================================== */
        *, *::before, *::after {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }

        html {
            scroll-behavior: smooth;
            scrollbar-gutter: stable;
        }

        body {
            font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
            background-color: var(--bg-cold-ivory);
            color: var(--text-primary);
            line-height: 1.6;
            overflow-x: hidden;
        }

        a {
            text-decoration: none !important;
        }

        /* ========================================
           Texture Layers (Global Background)
           ======================================== */
        .texture-layer {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
            z-index: -10;
        }

        /* 1. 亚麻纸纹理 (z-index: -4) */
        .texture-linen {
            z-index: -4;
            background-image: url("data:image/svg+xml,%3Csvg width='400' height='400' viewBox='0 0 400 400' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='linenNoise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='5' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23linenNoise)' opacity='0.03'/%3E%3C/svg%3E");
        }

        /* 2. 细密点阵纹理 (z-index: -3) */
        .texture-dots {
            z-index: -3;
            background-image: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='%23A67B5B' fill-opacity='0.04'%3E%3Ccircle cx='2' cy='2' r='1'/%3E%3Ccircle cx='32' cy='32' r='1'/%3E%3C/g%3E%3C/svg%3E");
        }

        /* 3. 交叉网格纹理 (z-index: -2) */
        .texture-grid {
            z-index: -2;
            background-image: 
                linear-gradient(rgba(166, 123, 91, 0.02) 1px, transparent 1px),
                linear-gradient(90deg, rgba(166, 123, 91, 0.02) 1px, transparent 1px),
                linear-gradient(rgba(166, 123, 91, 0.015) 1px, transparent 1px),
                linear-gradient(90deg, rgba(166, 123, 91, 0.015) 1px, transparent 1px);
            background-size: 100px 100px, 100px 100px, 20px 20px, 20px 20px;
        }

        /* ========================================
           Navigation
           ======================================== */
        .navbar {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            height: 72px;
            z-index: 1000;
            background: linear-gradient(180deg, #FAFBFC 0%, #F6F7F9 100%);
            border-bottom: 1px solid var(--border-copper-light);
            transition: all 0.3s var(--ease-smooth);
        }

        .navbar.scrolled {
            border-bottom-color: var(--border-copper-medium);
            box-shadow: 0 4px 20px rgba(166, 123, 91, 0.1);
        }

        .navbar-container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 64px;
            height: 100%;
            display: flex;
            align-items: center;
            justify-content: space-between;
        }

        .nav-brand {
            display: flex;
            align-items: center;
            gap: 12px;
        }

        .nav-logo {
            font-family: 'Noto Serif SC', serif;
            font-size: 22px;
            font-weight: 600;
            color: var(--text-primary);
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 12px;
        }

        .nav-logo-img {
            height: 40px;
            width: auto;
            object-fit: contain;
        }

        .nav-tagline {
            font-size: 14px;
            color: var(--text-secondary);
            letter-spacing: 2px;
            font-weight: 400;
        }

        .beta-badge {
            font-size: 11px;
            font-weight: 500;
            color: var(--accent-copper);
            background: rgba(166, 123, 91, 0.12);
            padding: 2px 8px;
            border-radius: 4px;
            margin-left: 4px;
            letter-spacing: 0.5px;
            font-family: 'Noto Sans SC', sans-serif;
        }

        .nav-menu {
            display: flex;
            align-items: center;
            gap: 44px;
            margin-left: auto;
        }

        .nav-link {
            font-size: 17px;
            color: var(--text-secondary);
            text-decoration: none;
            position: relative;
            padding: 4px 0;
            transition: color 0.2s ease;
        }

        .nav-link::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 1.5px;
            background: var(--accent-copper);
            transition: width 0.3s var(--ease-smooth);
        }

        .nav-link:hover,
        .nav-link.active {
            color: var(--text-primary);
        }

        .nav-link:hover::after,
        .nav-link.active::after {
            width: 100%;
        }

        .nav-actions {
            display: flex;
            align-items: center;
            gap: 16px;
        }

        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            padding: 10px 24px;
            font-size: 14px;
            font-weight: 500;
            border-radius: 24px;
            cursor: pointer;
            transition: all 0.2s ease;
            text-decoration: none;
            border: none;
            font-family: inherit;
        }

        .btn-primary {
            background: var(--accent-copper);
            color: white;
            position: relative;
            overflow: hidden;
            box-shadow: 0 2px 6px rgba(139, 69, 19, 0.25);
        }

        .btn-primary::before {
            content: '';
            position: absolute;
            top: 0;
            left: -100%;
            width: 100%;
            height: 100%;
            background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
            transition: left 0.6s ease;
        }

        .btn-primary:hover {
            background: var(--accent-copper-hover);
            transform: translateY(-1px);
            box-shadow: var(--shadow-hover);
        }

        .btn-primary:hover::before {
            left: 100%;
        }

        .btn-secondary {
            background: transparent;
            color: var(--text-secondary);
            border: 1px solid var(--border-copper-medium);
        }

        .btn-secondary:hover {
            background: var(--accent-copper);
            color: white;
            border-color: var(--accent-copper);
        }

        .btn-large {
            padding: 14px 28px;
            font-size: 15px;
        }

        /* Page Header */
        .page-header {
            padding: 120px 64px 40px;
            text-align: center;
        }

        .page-title {
            font-family: 'Noto Serif SC', serif;
            font-size: 36px;
            font-weight: 700;
            margin-bottom: 16px;
            color: var(--text-primary);
        }

        .page-subtitle,
        .page-intro {
            font-size: 16px;
            color: var(--text-secondary);
        }

        .page-intro {
            max-width: 700px;
            margin: 0 auto;
            line-height: 1.8;
        }

        .footer {
            padding: 64px;
            border-top: 1px solid var(--border-copper-light);
        }

        .footer-container {
            max-width: 1400px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: 1.5fr 1.5fr 1fr 1fr 1fr;
            gap: 48px;
        }

        /* Column 1: Brand & Social */
        .footer-brand {
            display: flex;
            flex-direction: column;
        }

        .footer-logo {
            font-family: 'Noto Serif SC', serif;
            font-size: 24px;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: 20px;
        }

        .footer-social {
            display: flex;
            gap: 8px;
            margin-bottom: 24px;
        }

        .social-link {
            width: 40px;
            height: 40px;
            display: flex;
            align-items: center;
            justify-content: center;
            border-radius: 10px;
            background: var(--bg-cold-ivory);
            color: var(--text-tertiary);
            transition: all 0.2s ease;
        }

        .social-link:hover {
            background: var(--accent-copper);
            color: white;
            transform: translateY(-2px);
        }

        .social-link svg {
            width: 22px;
            height: 22px;
        }
        .social-link img {
            width: 24px;
            height: 24px;
            object-fit: contain;
        }

        /* Column 2: Copyright & ICP */
        .footer-legal {
            font-size: 13px;
            color: var(--text-secondary);
            line-height: 2;
        }

        .footer-legal a {
            color: var(--text-secondary);
            text-decoration: none;
            display: block;
        }

        .footer-legal a:hover {
            color: var(--accent-copper);
        }

        /* Columns 3-5: Links */
        .footer-column-title {
            font-size: 15px;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: 16px;
        }

        .footer-links {
            display: flex;
            flex-direction: column;
            gap: 12px;
        }

        .footer-link {
            font-size: 14px;
            color: var(--text-secondary);
            text-decoration: none;
            transition: color 0.2s ease;
        }

        .footer-link:hover {
            color: var(--accent-copper);
        }

        /* ========================================
           Modal (Education Overlay)
           ======================================== */
        .modal-overlay {
            position: fixed;
            inset: 0;
            background: rgba(0, 0, 0, 0.5);
            backdrop-filter: blur(4px);
            z-index: 2000;
            display: none;
            align-items: center;
            justify-content: center;
            padding: 24px;
            opacity: 0;
            transition: opacity 0.3s ease;
        }

        .modal-overlay.active {
            display: flex;
            opacity: 1;
        }

        .modal {
            background: var(--porcelain-white);
            border-radius: var(--radius-soft);
            max-width: 640px;
            width: 100%;
            max-height: 80vh;
            overflow: hidden;
            box-shadow: 0 24px 48px rgba(0, 0, 0, 0.15);
            transform: translateY(20px);
            transition: transform 0.3s var(--ease-smooth);
            background-image: url("data:image/svg+xml,%3Csvg width='8' height='8' viewBox='0 0 8 8' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M0 0h8v8H0z' fill='none'/%3E%3Cpath d='M0 4h8M4 0v8' stroke='%23A67B5B' stroke-width='0.5' opacity='0.03'/%3E%3C/svg%3E");
        }

        .modal-overlay.active .modal {
            transform: translateY(0);
        }

        .modal-header {
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 20px 24px;
            border-bottom: 1px solid var(--border-copper-light);
        }

        .modal-title {
            font-family: 'Noto Serif SC', serif;
            font-size: 18px;
            font-weight: 600;
        }

        .modal-close {
            width: 32px;
            height: 32px;
            border: none;
            background: var(--bg-warm-cream);
            border-radius: 50%;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 18px;
            color: var(--text-secondary);
            transition: all 0.2s ease;
        }

        .modal-close:hover {
            background: var(--accent-copper);
            color: white;
        }

        .modal-body {
            padding: 24px;
            overflow-y: auto;
            max-height: calc(80vh - 140px);
        }

        .modal-step {
            display: none;
            animation: fadeIn 0.4s ease;
        }

        .modal-step.active {
            display: block;
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .step-title {
            font-family: 'Noto Serif SC', serif;
            font-size: 24px;
            font-weight: 600;
            margin-bottom: 24px;
            color: var(--text-primary);
        }

        .features-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 16px;
            margin-bottom: 24px;
        }

        .feature-item {
            text-align: center;
            padding: 20px;
            background: var(--bg-cold-ivory);
            border-radius: var(--radius-porcelain);
        }

        .feature-icon {
            font-size: 32px;
            margin-bottom: 12px;
        }

        .feature-title {
            font-size: 14px;
            font-weight: 500;
            margin-bottom: 4px;
        }

        .feature-desc {
            font-size: 12px;
            color: var(--text-tertiary);
        }

        .tech-list {
            display: flex;
            flex-direction: column;
            gap: 12px;
            margin-bottom: 24px;
        }

        .tech-item {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 12px 16px;
            background: var(--bg-cold-ivory);
            border-radius: var(--radius-porcelain);
        }

        .tech-icon {
            font-size: 22px;
        }

        .warning-box {
            padding: 16px;
            background: rgba(212, 175, 55, 0.1);
            border-left: 3px solid var(--accent-gold);
            border-radius: 0 var(--radius-porcelain) var(--radius-porcelain) 0;
            margin-bottom: 24px;
        }

        .warning-box p {
            font-size: 13px;
            color: var(--ink-brown);
            margin: 0;
        }

        .download-section {
            text-align: center;
            padding: 32px;
            background: linear-gradient(135deg, rgba(166, 123, 91, 0.05), rgba(212, 175, 55, 0.05));
            border-radius: var(--radius-porcelain);
            margin-bottom: 24px;
        }

        .download-btn-large {
            display: inline-flex;
            align-items: center;
            gap: 12px;
            padding: 16px 32px;
            background: var(--accent-copper);
            color: white;
            font-size: 16px;
            font-weight: 500;
            border-radius: 32px;
            text-decoration: none;
            margin-bottom: 12px;
            transition: all 0.2s ease;
            background-image: url("data:image/svg+xml,%3Csvg width='4' height='4' viewBox='0 0 4 4' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M0 4L4 0' stroke='%23fff' stroke-width='0.5' opacity='0.1'/%3E%3C/svg%3E");
        }

        .download-btn-large:hover {
            background: var(--accent-copper-hover);
            transform: translateY(-2px);
            box-shadow: var(--shadow-hover);
        }

        .download-meta {
            font-size: 13px;
            color: var(--text-tertiary);
        }

        .modal-footer {
            padding: 16px 24px;
            border-top: 1px solid var(--border-copper-light);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .step-indicator {
            display: flex;
            gap: 8px;
        }

        .step-dot {
            width: 8px;
            height: 8px;
            border-radius: 50%;
            background: var(--border-copper-medium);
            transition: all 0.2s ease;
        }

        .step-dot.active {
            background: var(--accent-copper);
            width: 24px;
            border-radius: 4px;
        }

        .modal-actions {
            display: flex;
            gap: 12px;
        }

        .btn-small {
            padding: 8px 20px;
            font-size: 13px;
        }

        .privacy-note {
            text-align: center;
            font-size: 12px;
            color: var(--text-tertiary);
            margin-top: 16px;
        }


        /* ========================================
           Responsive
           ======================================== */
        @media (max-width: 768px) {
            .navbar-container {
                padding: 0 24px;
            }
            .nav-menu {
                display: none;
            }
            .nav-tagline {
                display: none;
            }
            .page-header {
                padding: 100px 24px 32px;
            }
            .page-title {
                font-size: 28px;
            }
            .footer {
                padding: 48px 24px;
            }
            .footer-container {
                grid-template-columns: 1fr;
                gap: 32px;
            }
        }