:root {
            --bt74-primary: #4285F4;
            --bt74-success: #34A853;
            --bt74-warning: #FBBC05;
            --bt74-danger: #EA4335;
            --bt74-bg: #0b0e14;
            --bt74-surface: #1a1d23;
            --bt74-text: #e8eaed;
            --bt74-text-muted: #9aa0a6;
            --bt74-glass: rgba(255, 255, 255, 0.05);
            --bt74-border: rgba(255, 255, 255, 0.1);
            --bt74-font-main: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
            --bt74-font-mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
        }

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

        body {
            background-color: var(--bt74-bg);
            color: var(--bt74-text);
            font-family: var(--bt74-font-main);
            line-height: 1.6;
            overflow-x: hidden;
            word-break: keep-all;
        }

        /* 布局容器 */
        .bt74-container {
            max-width: 1400px;
            margin: 0 auto;
            padding: 0 48px;
            width: 100%;
        }

        @media (max-width: 768px) {
            .bt74-container {
                padding: 0 24px;
            }
        }

        /* 导航栏 */
        .bt74-header {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 1000;
            background: rgba(11, 14, 20, 0.8);
            backdrop-filter: blur(20px);
            border-bottom: 1px solid var(--bt74-border);
        }

        .bt74-nav-wrapper {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: space-between;
            height: 80px;
        }

        .bt74-logo {
            flex: 0 0 auto;
            min-width: 0;
        }

        .bt74-logo img {
            height: 32px;
            width: auto;
            display: block;
        }

        .bt74-nav-list {
            display: flex;
            flex-wrap: wrap;
            list-style: none;
            gap: 8px;
            min-width: 0;
        }

        .bt74-nav-item a {
            text-decoration: none;
            color: var(--bt74-text-muted);
            padding: 8px 16px;
            font-size: 14px;
            font-weight: 500;
            border-radius: 20px;
            transition: all 0.3s ease;
            white-space: nowrap;
        }

        .bt74-nav-item a:hover {
            color: var(--bt74-text);
            background: var(--bt74-glass);
        }

        .bt74-nav-item a.bt74-active {
            color: var(--bt74-primary);
            background: rgba(66, 133, 244, 0.1);
        }

        @media (max-width: 1024px) {
            .bt74-nav-wrapper {
                height: auto;
                padding: 16px 0;
            }
            .bt74-nav-list {
                margin-top: 16px;
                width: 100%;
                justify-content: center;
            }
        }

        /* Hero 区块 - 独特非线性布局 */
        .bt74-hero {
            padding: 180px 0 100px;
            position: relative;
            overflow: hidden;
            display: flex;
            flex-wrap: wrap;
            min-height: 80vh;
            align-items: center;
        }

        .bt74-hero-content {
            flex: 1;
            min-width: 320px;
            position: relative;
            z-index: 2;
        }

        .bt74-hero-visual {
            flex: 1;
            min-width: 320px;
            display: flex;
            justify-content: center;
            align-items: center;
            position: relative;
        }

        .bt74-title {
            font-size: clamp(2.5rem, 5vw + 1rem, 4.5rem);
            line-height: 1.1;
            font-weight: 800;
            margin-bottom: 24px;
            background: linear-gradient(135deg, #fff 0%, #4285F4 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            word-break: break-word;
        }

        .bt74-subtitle {
            font-size: clamp(1.1rem, 1vw + 0.5rem, 1.5rem);
            color: var(--bt74-text-muted);
            max-width: 600px;
            margin-bottom: 40px;
            line-height: 1.6;
        }

        /* 模拟开发者工具视觉 */
        .bt74-dev-mockup {
            width: 100%;
            max-width: 600px;
            background: var(--bt74-surface);
            border-radius: 12px;
            border: 1px solid var(--bt74-border);
            box-shadow: 0 32px 64px rgba(0,0,0,0.5);
            font-family: var(--bt74-font-mono);
            padding: 24px;
            position: relative;
            transform: perspective(1000px) rotateY(-10deg) rotateX(5deg);
            transition: transform 0.5s ease;
        }

        .bt74-dev-mockup:hover {
            transform: perspective(1000px) rotateY(0deg) rotateX(0deg);
        }

        .bt74-code-line {
            display: flex;
            gap: 12px;
            margin-bottom: 8px;
            font-size: 14px;
        }

        .bt74-code-num { color: #5f6368; user-select: none; }
        .bt74-code-tag { color: #ea4335; }
        .bt74-code-attr { color: #fbbc05; }
        .bt74-code-val { color: #34a853; }

        /* 核心特性区 */
        .bt74-section {
            padding: 96px 0;
            word-break: break-word;
        }

        .bt74-section-header {
            margin-bottom: 64px;
            text-align: center;
        }

        .bt74-section-title {
            font-size: clamp(2rem, 3vw, 3rem);
            margin-bottom: 16px;
        }

        .bt74-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
            gap: 32px;
        }

        .bt74-card {
            background: var(--bt74-glass);
            border: 1px solid var(--bt74-border);
            border-radius: 24px;
            padding: 40px;
            transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
            display: flex;
            flex-direction: column;
            gap: 20px;
        }

        .bt74-card:hover {
            transform: translateY(-12px);
            background: rgba(255, 255, 255, 0.08);
            border-color: var(--bt74-primary);
        }

        .bt74-card-icon {
            font-size: 40px;
            width: 64px;
            height: 64px;
            display: flex;
            align-items: center;
            justify-content: center;
            background: rgba(66, 133, 244, 0.1);
            border-radius: 16px;
            color: var(--bt74-primary);
        }

        .bt74-card-title {
            font-size: 24px;
            font-weight: 700;
        }

        .bt74-card-desc {
            color: var(--bt74-text-muted);
            font-size: 16px;
            line-height: 1.8;
        }

        .bt74-badge {
            display: inline-block;
            padding: 4px 12px;
            border-radius: 12px;
            font-size: 12px;
            font-weight: 600;
            text-transform: uppercase;
            background: rgba(255, 255, 255, 0.1);
            color: var(--bt74-text);
            align-self: flex-start;
        }

        /* 动态区块样式 */
        .bt74-dynamic-list {
            display: flex;
            flex-wrap: wrap;
            gap: 24px;
        }

        .bt74-dynamic-item {
            flex: 1;
            min-width: 300px;
            border-left: 4px solid var(--bt74-primary);
            padding-left: 24px;
            margin-bottom: 32px;
        }

        /* 页脚 */
        .bt74-footer {
            padding: 96px 0 48px;
            border-top: 1px solid var(--bt74-border);
            margin-top: 64px;
        }

        .bt74-footer-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 48px;
            margin-bottom: 64px;
        }

        .bt74-footer-brand {
            font-size: 24px;
            font-weight: 700;
            color: var(--bt74-text);
            margin-bottom: 16px;
        }

        .bt74-footer-links {
            list-style: none;
        }

        .bt74-footer-links li {
            margin-bottom: 12px;
        }

        .bt74-footer-links a {
            color: var(--bt74-text-muted);
            text-decoration: none;
            font-size: 14px;
            transition: color 0.3s;
        }

        .bt74-footer-links a:hover {
            color: var(--bt74-primary);
        }

        .bt74-copyright {
            text-align: center;
            color: var(--bt74-text-muted);
            font-size: 14px;
            padding-top: 48px;
            border-top: 1px solid var(--bt74-border);
        }

        /* 装饰背景 */
        .bt74-bg-glow {
            position: absolute;
            width: 600px;
            height: 600px;
            background: radial-gradient(circle, rgba(66, 133, 244, 0.15) 0%, transparent 70%);
            top: -200px;
            right: -200px;
            z-index: 1;
            pointer-events: none;
        }

        /* 响应式调整 */
        @media (max-width: 768px) {
            .bt74-hero {
                padding-top: 140px;
                text-align: center;
            }
            .bt74-hero-content {
                order: 2;
            }
            .bt74-hero-visual {
                order: 1;
                margin-bottom: 48px;
            }
            .bt74-dev-mockup {
                transform: none;
            }
            .bt74-title {
                font-size: 3rem;
            }
            .bt74-subtitle {
                margin: 0 auto 40px;
            }
        }