:root {
            /* 高级深色主题体系 */
            --bg-base: #000000;
            --bg-surface: #0a0a0a;
            --bg-surface-elevated: #121212;

            --text-primary: #ffffff;
            --text-secondary: #a1a1aa;
            --text-tertiary: #92929c;

            --brand-blue: #2563eb;
            --brand-purple: #9333ea;
            --brand-gradient: linear-gradient(135deg, var(--brand-blue), var(--brand-purple));

            --border-subtle: rgba(255, 255, 255, 0.08);
            --border-focus: rgba(255, 255, 255, 0.2);
            --border-active: rgba(147, 51, 234, 0.4);

            /* 排版 */
            --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
            --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

            /* 布局参数 */
            --content-max-width: 1200px;
            --section-spacing-y: 160px;
            --header-height: 72px;
        }

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

        html {
            scroll-behavior: smooth;
            background-color: var(--bg-base);
            color: var(--text-primary);
            font-family: var(--font-sans);
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            overflow-x: hidden;
        }

        body {
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            overflow-x: hidden;
        }

        /* 基础与可访问性 */
        a { text-decoration: none; color: inherit; }
        ul, ol { list-style: none; }
        img, svg { display: block; max-width: 100%; height: auto; }
        button { background: none; border: none; font: inherit; cursor: pointer; color: inherit; }

        a:focus-visible, button:focus-visible, summary:focus-visible {
            outline: 2px solid var(--text-primary);
            outline-offset: 2px;
            border-radius: 4px;
        }

        /* 隐藏辅助类 */
        .sr-only {
            position: absolute;
            width: 1px;
            height: 1px;
            padding: 0;
            margin: -1px;
            overflow: hidden;
            clip: rect(0, 0, 0, 0);
            white-space: nowrap;
            border-width: 0;
        }

        .hidden { display: none !important; }

        .container {
            width: 100%;
            max-width: var(--content-max-width);
            margin: 0 auto;
            padding: 0 24px;
        }

        /* 弹性布局工具类 */
        .flex { display: flex; }
        .flex-col { flex-direction: column; }
        .items-center { align-items: center; }
        .justify-center { justify-content: center; }
        .justify-between { justify-content: space-between; }
        .gap-2 { gap: 8px; }
        .gap-3 { gap: 12px; }
        .gap-4 { gap: 16px; }
        .gap-6 { gap: 24px; }
        .gap-8 { gap: 32px; }
        .gap-12 { gap: 48px; }
        .gap-16 { gap: 64px; }
        .flex-wrap { flex-wrap: wrap; }
        .flex-1 { flex: 1; }

        /* 间距工具类 */
        .mt-2 { margin-top: 8px; }
        .mt-4 { margin-top: 16px; }
        .mt-6 { margin-top: 24px; }
        .mt-8 { margin-top: 32px; }
        .mt-12 { margin-top: 48px; }
        .mb-2 { margin-bottom: 8px; }
        .mb-4 { margin-bottom: 16px; }
        .mb-6 { margin-bottom: 24px; }
        .mb-8 { margin-bottom: 32px; }
        .mb-12 { margin-bottom: 48px; }
        .py-16 { padding-top: 64px; padding-bottom: 64px; }

        /* 文本排版 */
        .text-center { text-align: center; }
        .text-left { text-align: left; }
        .text-sm { font-size: 14px; }
        .text-base { font-size: 16px; }
        .text-lg { font-size: 18px; }
        .text-xl { font-size: 20px; }
        .text-2xl { font-size: 24px; }
        .font-light { font-weight: 300; }
        .font-normal { font-weight: 400; }
        .font-medium { font-weight: 500; }
        .text-primary { color: var(--text-primary); }
        .text-secondary { color: var(--text-secondary); }
        .text-tertiary { color: var(--text-tertiary); }
        .text-brand { color: var(--brand-purple); }
        .leading-relaxed { line-height: 1.6; }
        .leading-tight { line-height: 1.2; }

        /* 核心按钮设计 */
        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            border-radius: 9999px;
            font-weight: 500;
            transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
            position: relative;
        }

        .btn-primary {
            padding: 14px 32px;
            font-size: 16px;
            color: var(--text-primary);
            background: var(--brand-gradient);
            box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.1) inset, 0 8px 20px -8px rgba(147, 51, 234, 0.4);
        }

        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.2) inset, 0 12px 24px -8px rgba(147, 51, 234, 0.6);
        }

        .btn-secondary {
            padding: 10px 24px;
            font-size: 14px;
            color: var(--text-primary);
            background: var(--bg-surface-elevated);
            border: 1px solid var(--border-subtle);
        }

        .btn-secondary:hover {
            background: rgba(255, 255, 255, 0.05);
            border-color: var(--border-focus);
        }

        .btn-outline {
            padding: 10px 24px;
            font-size: 14px;
            color: var(--text-primary);
            background: transparent;
            border: 1px solid var(--border-subtle);
        }
        .btn-outline:hover {
            background: var(--text-primary);
            color: var(--bg-base);
        }

        /* 导航栏 */
        .site-header {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 100;
            height: var(--header-height);
            display: flex;
            align-items: center;
            background: rgba(0, 0, 0, 0.5);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border-bottom: 1px solid transparent;
            transition: border-color 0.3s, background-color 0.3s;
        }

        .site-header.is-scrolled {
            border-bottom-color: var(--border-subtle);
            background: rgba(0, 0, 0, 0.8);
        }

        .nav-brand {
            font-size: 18px;
            font-weight: 500;
            letter-spacing: -0.02em;
        }

        .nav-brand img {
            width: 28px;
            height: 28px;
            border-radius: 6px;
        }

        .nav-links a {
            font-size: 14px;
            color: var(--text-secondary);
            transition: color 0.2s;
        }
        .nav-links a:hover { color: var(--text-primary); }

        .mobile-menu-toggle { display: none; width: 40px; height: 40px; }

        @media (max-width: 768px) {
            .nav-links {
                position: absolute;
                top: 100%;
                left: 0;
                right: 0;
                background: var(--bg-surface);
                flex-direction: column;
                padding: 24px;
                border-bottom: 1px solid var(--border-subtle);
                opacity: 0;
                visibility: hidden;
                transform: translateY(-10px);
                transition: all 0.3s ease;
            }
            .nav-links.is-active {
                opacity: 1;
                visibility: visible;
                transform: translateY(0);
            }
            .nav-actions { display: none; }
            .mobile-menu-toggle { display: flex; }
        }

        /* 首屏 Hero 区 */
        .hero {
            position: relative;
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            overflow: hidden;
            padding-top: var(--header-height);
        }

        .hero-canvas-container {
            position: absolute;
            inset: 0;
            z-index: 0;
            pointer-events: none;
            /* 提供一个深色遮罩，确保文字始终可读 */
            background: radial-gradient(circle at center, transparent 0%, var(--bg-base) 100%);
        }

        #hero-canvas {
            width: 100%;
            height: 100%;
            display: block;
        }

        .hero-content {
            position: relative;
            z-index: 1;
            max-width: 800px;
            padding: 0 24px;
            text-align: center;
        }

        .hero-title {
            font-size: clamp(48px, 8vw, 84px);
            font-weight: 300;
            letter-spacing: -0.04em;
            line-height: 1.1;
            margin-bottom: 32px;
            color: var(--text-primary);
        }

        .hero-subtitle {
            font-size: clamp(16px, 2vw, 20px);
            color: var(--text-secondary);
            max-width: 540px;
            margin: 0 auto 48px;
        }

        /* 内容区块基础 */
        .section-padding { padding: var(--section-spacing-y) 0; }
        .section-header { margin-bottom: 80px; }
        .section-header h2 {
            font-size: clamp(32px, 5vw, 48px);
            font-weight: 400;
            letter-spacing: -0.02em;
            margin-bottom: 16px;
        }
        .section-header p {
            font-size: 20px;
            color: var(--text-secondary);
            max-width: 600px;
        }

        /* 交互式产品舞台 (截图切换) */
        .product-stage {
            background: var(--bg-surface);
            border-top: 1px solid var(--border-subtle);
            border-bottom: 1px solid var(--border-subtle);
        }

        .stage-tabs {
            display: flex;
            justify-content: center;
            gap: 16px;
            margin-bottom: 64px;
            flex-wrap: wrap;
        }

        .stage-tab-btn {
            padding: 12px 24px;
            font-size: 15px;
            color: var(--text-secondary);
            background: transparent;
            border: 1px solid transparent;
            border-radius: 9999px;
            transition: all 0.2s;
        }

        .stage-tab-btn:hover { color: var(--text-primary); }
        .stage-tab-btn[aria-selected="true"] {
            color: var(--text-primary);
            background: rgba(255, 255, 255, 0.05);
            border-color: var(--border-active);
        }

        .stage-display {
            position: relative;
            max-width: 340px;
            margin: 0 auto;
            aspect-ratio: 1080 / 2424;
        }

        .mockup-frame {
            position: absolute;
            inset: 0;
            border-radius: 40px;
            padding: 12px;
            background: var(--bg-surface-elevated);
            border: 1px solid var(--border-subtle);
            box-shadow: 0 32px 64px -16px rgba(0, 0, 0, 0.8);
            z-index: 2;
        }

        /* 发光背景 */
        .stage-display::before {
            content: '';
            position: absolute;
            inset: -40px;
            background: radial-gradient(circle at center, var(--brand-blue), transparent 60%);
            opacity: 0.15;
            filter: blur(40px);
            z-index: 1;
            border-radius: inherit;
        }

        .mockup-image {
            width: 100%;
            height: 100%;
            border-radius: 28px;
            object-fit: cover;
            position: absolute;
            top: 12px;
            left: 12px;
            width: calc(100% - 24px);
            height: calc(100% - 24px);
            opacity: 0;
            transition: opacity 0.5s ease;
            background: var(--bg-base);
        }

        .mockup-image.is-active { opacity: 1; z-index: 3; }

        /* 功能叙事列 */
        .feature-grid {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 80px;
            align-items: center;
        }

        .feature-text h3 {
            font-size: 28px;
            font-weight: 500;
            margin-bottom: 20px;
        }

        @media (max-width: 768px) {
            .feature-grid { grid-template-columns: 1fr; gap: 40px; }
            .feature-grid.reverse .feature-text { grid-row: 1; }
        }

        /* 三步配对指南 */
        .steps-container {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 40px;
        }

        .step-card {
            background: var(--bg-surface);
            padding: 40px 32px;
            border-radius: 24px;
            border: 1px solid var(--border-subtle);
            position: relative;
        }

        .step-number {
            font-size: 48px;
            font-weight: 300;
            color: var(--text-primary);
            opacity: 0.2;
            margin-bottom: 16px;
            font-family: var(--font-mono);
        }

        /* 手风琴 FAQ */
        .faq-item {
            border-bottom: 1px solid var(--border-subtle);
        }
        .faq-item:first-child { border-top: 1px solid var(--border-subtle); }

        .faq-item summary {
            padding: 24px 0;
            font-size: 18px;
            font-weight: 500;
            cursor: pointer;
            list-style: none;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .faq-item summary::-webkit-details-marker { display: none; }

        .faq-item summary::after {
            content: "+";
            font-size: 24px;
            font-weight: 300;
            color: var(--text-secondary);
            transition: transform 0.3s ease;
        }
        .faq-item[open] summary::after { transform: rotate(45deg); }

        .faq-body {
            padding-bottom: 24px;
            color: var(--text-secondary);
            font-size: 15px;
            line-height: 1.6;
        }

        /* 下载中心 */
        .download-layout {
            display: flex;
            gap: 64px;
            align-items: stretch;
        }

        .download-card {
            flex: 1;
            padding: 48px;
            background: var(--bg-surface);
            border-radius: 32px;
            border: 1px solid var(--border-subtle);
        }

        .code-snippet {
            display: block;
            padding: 12px 16px;
            background: rgba(255,255,255,0.03);
            border-radius: 8px;
            font-family: var(--font-mono);
            font-size: 13px;
            word-break: break-all;
            border: 1px solid var(--border-subtle);
            color: var(--text-primary);
            margin: 16px 0;
        }

        @media (max-width: 900px) {
            .steps-container { grid-template-columns: 1fr; }
            .download-layout { flex-direction: column; }
        }

        /* 页脚 */
        .site-footer {
            border-top: 1px solid var(--border-subtle);
            padding: 64px 0 40px;
            background: var(--bg-surface);
        }

        /* 渐显动画基础 */
        .js-enabled .reveal-element.will-reveal {
            opacity: 0;
            transform: translateY(30px);
            transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1), transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
        }
        .js-enabled .reveal-element.is-visible {
            opacity: 1;
            transform: translateY(0);
        }
        @media (prefers-reduced-motion: reduce) {
            .js-enabled .reveal-element.will-reveal {
                opacity: 1;
                transform: none;
                transition: none;
            }
        }
.production-style-1 { background: var(--bg-surface); }
.production-style-2 { max-width: 800px; }
.production-style-3 { background: var(--text-primary); color: var(--bg-base); border: none; }
.btn-secondary.production-style-3:hover,
.btn-secondary.production-style-3:focus-visible { background: #e5e5e5; color: #000; border: none; }
.production-style-4 { border-top: 1px solid var(--border-subtle); }
.production-style-5 { width: 200px; height: 200px; padding: 12px; background: white; border-radius: 16px; margin-bottom: 24px; }
.production-style-6 { width: 24px; }
/* Production integration keeps Gemini's new visual direction. */
html { scroll-padding-top: 96px; color-scheme: dark; }
[hidden] { display: none !important; }
.w-full { width: 100%; }
.mx-auto { margin-left: auto; margin-right: auto; }
.pt-8 { padding-top: 32px; }
.footer-about { max-width: 400px; }
.qr-description { max-width: 240px; }
.footer-bottom { border-top: 1px solid var(--border-subtle); }
.skip-link { position: fixed; left: 20px; top: -80px; z-index: 200; padding: 12px 20px; border-radius: 12px; background: #fff; color: #000; }
.skip-link:focus { top: 10px; }
.hero { min-height: 740px; min-height: max(740px, 100svh); padding: 120px 0 88px; isolation: isolate; }
.hero-canvas-container { background: radial-gradient(ellipse at 50% 52%, #11132e, transparent 65%); }
.hero-canvas-container::after { content: ''; position: absolute; inset: 0; background: radial-gradient(ellipse at 50% 48%, rgba(0,0,0,.38), transparent 60%), linear-gradient(0deg, #000, transparent 20%); }
.hero-title { line-height: 1.17; font-weight: 350; text-shadow: 0 2px 40px rgba(0,0,0,.6); }
.hero-subtitle { line-height: 1.85; color: #c1c0cc; }
.hero-meta { margin-top: 24px; color: var(--text-secondary); font-size: 12px; }
.hero-explore { display: inline-flex; gap: 14px; align-items: center; font-size: 13px; margin-top: 52px; color: var(--text-secondary); }
.hero-explore:hover { color: #fff; }
.stage-tabs { gap: 8px; }
.stage-display { max-width: 310px; }
.section-header p { line-height: 1.8; }
.section-header h2 { line-height: 1.4; }
.download-card { min-width: 0; }
.copy-status { display: block; color: var(--text-secondary); font-size: 13px; }
.mobile-menu-toggle { display: none; min-width: 44px; min-height: 44px; }
.footer-icon { width: 24px; }
@media (min-width: 768px) { .footer-main { flex-direction: row; } }
@media (min-width: 640px) { .footer-bottom { flex-direction: row; } }
@media (max-width: 1000px) and (min-width: 769px) { .nav-actions { display: none; } }
@media (max-width: 768px) {
 :root { --section-spacing-y: 88px; }
 .container { padding-left: 22px; padding-right: 22px; }
 .js-enabled .mobile-menu-toggle { display: flex; }
 .nav-links { gap: 24px; }
 .hero { min-height: max(720px, 100svh); padding-top: 112px; padding-bottom: 64px; }
 .hero-title { font-size: clamp(48px, 12vw, 64px); }
 .hero-subtitle { font-size: 15px; margin-bottom: 32px; }
 .hero-meta { font-size: 11px; }
 .hero-explore { margin-top: 40px; }
 .section-header { margin-bottom: 48px; }
 .section-header p { font-size: 16px; }
 .stage-tabs { gap: 4px; margin-bottom: 44px; }
 .stage-tab-btn { padding: 12px 16px; font-size: 14px; }
 .stage-display { max-width: 282px; }
 .feature-grid { gap: 28px; }
 .steps-container { gap: 20px; }
 .step-card { padding: 30px; }
 .download-layout { gap: 24px; }
 .download-card { padding: 28px 22px; border-radius: 24px; }
 .download-card .flex { flex-wrap: wrap; }
 .faq-item summary { font-size: 16px; gap: 16px; line-height: 1.6; }
 .faq-item summary::after { flex-shrink: 0; }
 .footer-main { gap: 36px; }
 .footer-links { gap: 40px; }
}
@media (prefers-reduced-motion: reduce) {
 *, *::before, *::after { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
 .js-enabled .reveal-element.will-reveal { opacity: 1; transform: none; }
}


/* Match each screenshot's original aspect ratio inside the device frame. */
.stage-display { aspect-ratio: auto; }
.mockup-frame { position: relative; }
.mockup-frame::before { content: ''; display: block; width: 100%; aspect-ratio: 1080 / 2424; }