:root {
            --tr7nn-primary: #4285F4;
            --tr7nn-red: #EA4335;
            --tr7nn-yellow: #FBBC04;
            --tr7nn-green: #34A853;
            --tr7nn-text-dark: #202124;
            --tr7nn-text-light: #5f6368;
            --tr7nn-bg-light: #f8f9fa;
            --tr7nn-white: #ffffff;
            --tr7nn-transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }

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

        body {
            font-family: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
            color: var(--tr7nn-text-dark);
            background-color: var(--tr7nn-white);
            line-height: 1.6;
            overflow-x: hidden;
            word-break: break-word;
        }

        /* Layout Container */
        .tr7nn-container {
            max-width: 1100px;
            margin: 0 auto;
            padding: 0 24px;
            width: 100%;
        }

        /* Navigation */
        .tr7nn-header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            background: rgba(255, 255, 255, 0.8);
            backdrop-filter: blur(10px);
            z-index: 1000;
            border-bottom: 1px solid rgba(0,0,0,0.05);
            transition: var(--tr7nn-transition);
        }

        .tr7nn-nav-wrapper {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            align-items: center;
            height: 72px;
        }

        .tr7nn-logo {
            flex-shrink: 0;
            min-width: 0;
        }

        .tr7nn-logo img {
            height: 32px;
            display: block;
        }

        .tr7nn-menu {
            display: flex;
            flex-wrap: wrap;
            list-style: none;
            gap: 16px;
        }

        .tr7nn-menu-item a {
            text-decoration: none;
            color: var(--tr7nn-text-light);
            font-size: 15px;
            font-weight: 500;
            padding: 8px 12px;
            border-radius: 4px;
            transition: var(--tr7nn-transition);
            white-space: normal;
        }

        .tr7nn-menu-item a:hover {
            background-color: rgba(66, 133, 244, 0.05);
            color: var(--tr7nn-primary);
        }

        .tr7nn-menu-item a.active {
            color: var(--tr7nn-primary);
            position: relative;
        }

        .tr7nn-menu-item a.active::after {
            content: '';
            position: absolute;
            bottom: -4px;
            left: 12px;
            right: 12px;
            height: 3px;
            background-color: var(--tr7nn-primary);
            border-radius: 2px;
        }

        /* Hero Section - Unique Centric Focus */
        .tr7nn-hero {
            padding: 160px 0 96px;
            background: radial-gradient(circle at 50% -20%, #e8f0fe 0%, #ffffff 60%);
            text-align: center;
        }

        .tr7nn-hero-content {
            max-width: 800px;
            margin: 0 auto;
        }

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

        .tr7nn-hero-subtitle {
            font-size: clamp(1.1rem, 2vw + 0.5rem, 1.4rem);
            color: var(--tr7nn-text-light);
            margin-bottom: 48px;
            max-width: 700px;
            margin-left: auto;
            margin-right: auto;
            line-height: 1.8;
        }

        .tr7nn-download-box {
            background: var(--tr7nn-white);
            padding: 40px;
            border-radius: 24px;
            box-shadow: 0 20px 40px rgba(0,0,0,0.08);
            display: inline-block;
            width: 100%;
            max-width: 500px;
            border: 1px solid rgba(0,0,0,0.03);
            transition: var(--tr7nn-transition);
        }

        .tr7nn-download-box:hover {
            transform: translateY(-8px);
            box-shadow: 0 30px 60px rgba(66, 133, 244, 0.12);
        }

        .tr7nn-btn-download {
            display: inline-block;
            background: linear-gradient(135deg, var(--tr7nn-primary), #1a73e8);
            color: white;
            padding: 20px 48px;
            border-radius: 50px;
            font-size: 18px;
            font-weight: 600;
            text-decoration: none;
            box-shadow: 0 4px 15px rgba(66, 133, 244, 0.3);
            transition: var(--tr7nn-transition);
            margin-bottom: 16px;
        }

        .tr7nn-btn-download:hover {
            transform: scale(1.02);
            box-shadow: 0 6px 20px rgba(66, 133, 244, 0.4);
        }

        .tr7nn-version-info {
            font-size: 13px;
            color: var(--tr7nn-text-light);
        }

        /* Security Section - Grid */
        .tr7nn-section-security {
            padding: 96px 0;
            background-color: var(--tr7nn-bg-light);
        }

        .tr7nn-section-header {
            margin-bottom: 64px;
            text-align: center;
        }

        .tr7nn-section-header h2 {
            font-size: clamp(1.8rem, 3vw + 0.5rem, 2.5rem);
            margin-bottom: 16px;
        }

        .tr7nn-security-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 32px;
        }

        .tr7nn-security-card {
            background: var(--tr7nn-white);
            padding: 32px;
            border-radius: 16px;
            border: 1px solid rgba(0,0,0,0.05);
            transition: var(--tr7nn-transition);
            min-width: 0;
        }

        .tr7nn-security-card:hover {
            border-color: var(--tr7nn-primary);
            box-shadow: 0 10px 30px rgba(0,0,0,0.05);
        }

        .tr7nn-card-protocol {
            font-size: 12px;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 1px;
            color: var(--tr7nn-primary);
            margin-bottom: 12px;
            display: block;
        }

        .tr7nn-card-title {
            font-size: 20px;
            margin-bottom: 16px;
            color: var(--tr7nn-text-dark);
        }

        .tr7nn-card-desc {
            font-size: 15px;
            color: var(--tr7nn-text-light);
            line-height: 1.7;
        }

        /* Features Section - Alternating Layout */
        .tr7nn-feature-block {
            padding: 80px 0;
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 64px;
        }

        .tr7nn-feature-block:nth-child(even) {
            flex-direction: row-reverse;
        }

        .tr7nn-feature-text {
            flex: 1;
            min-width: 300px;
        }

        .tr7nn-feature-visual {
            flex: 1;
            min-width: 300px;
            background: linear-gradient(135deg, #f1f3f4 0%, #e8eaed 100%);
            height: 300px;
            border-radius: 24px;
            position: relative;
            overflow: hidden;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        /* Abstract CSS Graphic instead of Emoji */
        .tr7nn-browser-mock {
            width: 80%;
            height: 60%;
            background: white;
            border-radius: 8px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.1);
            position: relative;
            padding-top: 24px;
        }

        .tr7nn-mock-bar {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 24px;
            background: #dadce0;
            display: flex;
            align-items: center;
            padding: 0 8px;
            gap: 4px;
        }

        .tr7nn-dot {
            width: 8px;
            height: 8px;
            border-radius: 50%;
            background: #fff;
        }

        .tr7nn-feature-title {
            font-size: 32px;
            margin-bottom: 24px;
        }

        /* Footer */
        .tr7nn-footer {
            background-color: #f1f3f4;
            padding: 64px 0 32px;
            margin-top: 64px;
        }

        .tr7nn-footer-top {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            gap: 48px;
            margin-bottom: 48px;
        }

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

        .tr7nn-footer-links {
            display: flex;
            flex-wrap: wrap;
            gap: 32px;
        }

        .tr7nn-footer-group h4 {
            font-size: 14px;
            text-transform: uppercase;
            margin-bottom: 20px;
            color: var(--tr7nn-text-dark);
        }

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

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

        .tr7nn-footer-group ul li a {
            text-decoration: none;
            color: var(--tr7nn-text-light);
            font-size: 14px;
            transition: var(--tr7nn-transition);
        }

        .tr7nn-footer-group ul li a:hover {
            color: var(--tr7nn-primary);
        }

        .tr7nn-footer-bottom {
            padding-top: 32px;
            border-top: 1px solid rgba(0,0,0,0.05);
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            align-items: center;
            font-size: 13px;
            color: var(--tr7nn-text-light);
        }

        /* Responsive */
        @media (max-width: 768px) {
            .tr7nn-menu {
                display: none; /* Simplification for mobile */
            }
            .tr7nn-hero {
                padding: 120px 0 64px;
            }
            .tr7nn-feature-block {
                text-align: center;
                gap: 32px;
            }
            .tr7nn-footer-top {
                flex-direction: column;
            }
        }