:root {
            --tr7nn-primary: #4285F4;
            --tr7nn-red: #EA4335;
            --tr7nn-yellow: #FBBC04;
            --tr7nn-green: #34A853;
            --tr7nn-text: #202124;
            --tr7nn-bg: #FFFFFF;
            --tr7nn-bg-alt: #F8F9FA;
            --tr7nn-border: #DADCE0;
            --tr7nn-spacing-unit: 8px;
            --tr7nn-max-width: 1100px;
        }

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

        body {
            font-family: "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
            color: var(--tr7nn-text);
            line-height: 1.6;
            background-color: var(--tr7nn-bg);
            word-break: break-word;
            overflow-x: hidden;
        }

        /* 导航系统 */
        .tr7nn-header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            background: rgba(255, 255, 255, 0.9);
            backdrop-filter: blur(10px);
            border-bottom: 1px solid var(--tr7nn-border);
            z-index: 1000;
            padding: 0 calc(5vw);
        }

        .tr7nn-nav-container {
            max-width: var(--tr7nn-max-width);
            margin: 0 auto;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            align-items: center;
            height: 72px;
        }

        .tr7nn-logo {
            flex: 0 0 auto;
            min-width: 0;
            display: flex;
            align-items: center;
        }

        .tr7nn-logo img {
            height: 32px;
            width: auto;
        }

        .tr7nn-nav-menu {
            display: flex;
            flex-wrap: wrap;
            list-style: none;
            gap: calc(var(--tr7nn-spacing-unit) * 3);
        }

        .tr7nn-nav-item a {
            text-decoration: none;
            color: #5F6368;
            font-size: 14px;
            font-weight: 500;
            transition: color 0.3s ease;
            position: relative;
            padding: 4px 0;
        }

        .tr7nn-nav-item a:hover {
            color: var(--tr7nn-primary);
        }

        .tr7nn-nav-item.active a {
            color: var(--tr7nn-primary);
        }

        .tr7nn-nav-item.active a::after {
            content: '';
            position: absolute;
            bottom: -24px;
            left: 0;
            width: 100%;
            height: 3px;
            background-color: var(--tr7nn-primary);
            border-radius: 3px 3px 0 0;
        }

        /* Hero 独特布局: 对角线分割视差感 */
        .tr7nn-hero {
            padding: 160px 5vw 80px;
            background: linear-gradient(135deg, #f1f3f4 0%, #ffffff 100%);
            position: relative;
            overflow: hidden;
        }

        .tr7nn-hero-content {
            max-width: var(--tr7nn-max-width);
            margin: 0 auto;
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 48px;
        }

        .tr7nn-hero-text {
            flex: 1;
            min-width: 320px;
        }

        .tr7nn-hero-visual {
            flex: 1;
            min-width: 320px;
            display: flex;
            justify-content: center;
            position: relative;
        }

        .tr7nn-shield-shape {
            width: 280px;
            height: 320px;
            background: var(--tr7nn-bg);
            border: 8px solid var(--tr7nn-primary);
            border-radius: 0 0 140px 140px;
            position: relative;
            box-shadow: 0 24px 48px rgba(66, 133, 244, 0.15);
            display: flex;
            align-items: center;
            justify-content: center;
            transition: transform 0.5s ease;
        }

        .tr7nn-shield-shape:hover {
            transform: translateY(-10px) rotate(2deg);
        }

        .tr7nn-shield-inner {
            width: 60%;
            height: 60%;
            border: 4px dashed var(--tr7nn-green);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 48px;
        }

        .tr7nn-hero h1 {
            font-size: clamp(2.5rem, 5vw + 1rem, 4rem);
            line-height: 1.1;
            margin-bottom: 24px;
            font-weight: 700;
            color: var(--tr7nn-text);
            word-break: keep-all;
        }

        .tr7nn-hero p {
            font-size: clamp(1.1rem, 2vw + 0.5rem, 1.4rem);
            color: #5F6368;
            max-width: 600px;
            margin-bottom: 32px;
        }

        /* 核心协议矩阵 */
        .tr7nn-matrix-section {
            padding: 96px 5vw;
            background-color: var(--tr7nn-bg);
        }

        .tr7nn-section-header {
            max-width: var(--tr7nn-max-width);
            margin: 0 auto 64px;
            text-align: center;
        }

        .tr7nn-section-header h2 {
            font-size: clamp(2rem, 3vw + 1rem, 2.8rem);
            margin-bottom: 16px;
        }

        .tr7nn-matrix-grid {
            max-width: var(--tr7nn-max-width);
            margin: 0 auto;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
            gap: 32px;
        }

        .tr7nn-matrix-card {
            background: var(--tr7nn-bg-alt);
            padding: 40px;
            border-radius: 24px;
            border: 1px solid var(--tr7nn-border);
            transition: all 0.3s ease;
            display: flex;
            flex-direction: column;
            min-width: 0;
        }

        .tr7nn-matrix-card:hover {
            transform: translateY(-8px);
            box-shadow: 0 12px 32px rgba(0,0,0,0.08);
            border-color: var(--tr7nn-primary);
        }

        .tr7nn-protocol-badge {
            display: inline-block;
            padding: 4px 12px;
            border-radius: 50px;
            font-size: 12px;
            font-weight: 700;
            text-transform: uppercase;
            margin-bottom: 20px;
            background: #E8F0FE;
            color: var(--tr7nn-primary);
            align-self: flex-start;
        }

        .tr7nn-matrix-card h3 {
            font-size: 24px;
            margin-bottom: 16px;
            color: var(--tr7nn-text);
        }

        .tr7nn-matrix-card p {
            font-size: 16px;
            color: #5F6368;
            line-height: 1.7;
            margin-bottom: 24px;
            flex-grow: 1;
        }

        .tr7nn-status-tag {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 14px;
            font-weight: 600;
        }

        .tr7nn-status-dot {
            width: 8px;
            height: 8px;
            border-radius: 50%;
            background-color: var(--tr7nn-green);
        }

        /* 动态内容区块 */
        .tr7nn-update-section {
            padding: 80px 5vw;
            background-color: #f8f9fa;
            border-top: 1px solid var(--tr7nn-border);
        }

        .tr7nn-update-container {
            max-width: var(--tr7nn-max-width);
            margin: 0 auto;
        }

        /* 按钮设计 */
        .tr7nn-btn {
            display: inline-block;
            padding: 16px 32px;
            border-radius: 50px;
            font-weight: 600;
            text-decoration: none;
            transition: all 0.3s ease;
            cursor: pointer;
            border: none;
            font-size: 16px;
        }

        .tr7nn-btn-primary {
            background-color: var(--tr7nn-primary);
            color: white;
            box-shadow: 0 4px 14px rgba(66, 133, 244, 0.3);
        }

        .tr7nn-btn-primary:hover {
            background-color: #1a73e8;
            transform: scale(1.02);
        }

        /* 页脚 */
        .tr7nn-footer {
            background: #202124;
            color: white;
            padding: 80px 5vw 40px;
        }

        .tr7nn-footer-top {
            max-width: var(--tr7nn-max-width);
            margin: 0 auto;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            gap: 48px;
            margin-bottom: 64px;
        }

        .tr7nn-footer-brand {
            flex: 1;
            min-width: 240px;
        }

        .tr7nn-footer-brand h2 {
            font-size: 24px;
            margin-bottom: 16px;
            color: white;
        }

        .tr7nn-footer-links {
            flex: 2;
            display: flex;
            flex-wrap: wrap;
            gap: 40px;
            min-width: 0;
        }

        .tr7nn-link-group {
            flex: 1;
            min-width: 140px;
        }

        .tr7nn-link-group h4 {
            font-size: 14px;
            margin-bottom: 20px;
            color: #9AA0A6;
            text-transform: uppercase;
            letter-spacing: 1px;
        }

        .tr7nn-link-group ul {
            list-style: none;
        }

        .tr7nn-link-group li {
            margin-bottom: 12px;
        }

        .tr7nn-link-group a {
            color: #BDC1C6;
            text-decoration: none;
            font-size: 14px;
            transition: color 0.2s;
        }

        .tr7nn-link-group a:hover {
            color: white;
        }

        .tr7nn-footer-bottom {
            max-width: var(--tr7nn-max-width);
            margin: 0 auto;
            padding-top: 32px;
            border-top: 1px solid #3C4043;
            text-align: center;
            color: #9AA0A6;
            font-size: 13px;
        }

        /* 响应式适配 */
        @media (max-width: 768px) {
            .tr7nn-nav-menu {
                display: none; /* 简化移动端，实际开发中会换成汉堡菜单 */
            }
            .tr7nn-hero {
                padding-top: 120px;
                text-align: center;
            }
            .tr7nn-hero-content {
                flex-direction: column;
            }
            .tr7nn-hero-text {
                order: 2;
            }
            .tr7nn-hero-visual {
                order: 1;
                margin-bottom: 40px;
            }
            .tr7nn-matrix-grid {
                grid-template-columns: 1fr;
            }
        }