/* ==================== 全局变量与基础 ==================== */
        :root {
            --bg-deep: #060d17;
            --bg-card: rgba(14, 22, 36, 0.75);
            --bg-card-hover: rgba(22, 32, 50, 0.9);
            --border-soft: #1e2d40;
            --border-glow: rgba(12, 230, 181, 0.22);
            --text-primary: #edf2f9;
            --text-secondary: #8899b4;
            --accent-teal: #0ce6b5;
            --accent-amber: #f0a500;
            --accent-purple: #8b5cf6;
            --gradient-hero: linear-gradient(135deg, #0ce6b5 0%, #6dd5ed 50%, #8b5cf6 100%);
            --gradient-subtle: linear-gradient(160deg, #080f1a 0%, #0c1522 100%);
            --radius-lg: 20px;
            --radius-xl: 28px;
            --shadow-glow-teal: 0 0 24px rgba(12, 230, 181, 0.25);
        }

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

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            background: var(--bg-deep);
            color: var(--text-primary);
            line-height: 1.55;
            -webkit-font-smoothing: antialiased;
        }

        .container {
            max-width: 1240px;
            margin: 0 auto;
            padding: 0 28px;
        }

        a {
            text-decoration: none;
            color: inherit;
            transition: color 0.2s;
        }

        /* ==================== 导航栏 (与首页相同) ==================== */
        header {
            background: rgba(6, 13, 23, 0.94);
            backdrop-filter: blur(14px);
            -webkit-backdrop-filter: blur(14px);
            border-bottom: 1px solid var(--border-glow);
            position: sticky;
            top: 0;
            z-index: 100;
        }

        .nav-bar {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            padding: 14px 0;
        }

        .brand {
            display: flex;
            flex-direction: column;
        }

        .brand-name {
            font-size: 1.7rem;
            font-weight: 800;
            background: var(--gradient-hero);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            letter-spacing: -0.5px;
            line-height: 1.2;
        }

        .brand-accent {
            color: var(--accent-teal);
            -webkit-text-fill-color: var(--accent-teal);
        }

        .brand-tagline {
            font-size: 0.68rem;
            color: var(--text-secondary);
            letter-spacing: 0.3px;
            margin-top: 1px;
        }

        .nav-menu {
            display: flex;
            gap: 1.8rem;
            align-items: center;
            flex-wrap: wrap;
        }

        .nav-link {
            font-size: 0.9rem;
            font-weight: 500;
            color: #b0c0d4;
            position: relative;
            padding: 4px 0;
            transition: color 0.25s;
        }

        .nav-link::after {
            content: '';
            position: absolute;
            bottom: -2px;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--accent-teal);
            transition: width 0.28s;
            box-shadow: var(--shadow-glow-teal);
        }

        .nav-link:hover,
        .nav-link.active {
            color: var(--accent-teal);
        }

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

        .menu-toggle {
            display: none;
            flex-direction: column;
            justify-content: space-between;
            width: 26px;
            height: 18px;
            background: transparent;
            border: none;
            cursor: pointer;
            padding: 0;
        }

        .menu-toggle span {
            width: 100%;
            height: 2px;
            background: #b0c0d4;
            border-radius: 2px;
            transition: all 0.3s;
        }

        .menu-toggle--active span:nth-child(1) {
            transform: translateY(8px) rotate(45deg);
        }
        .menu-toggle--active span:nth-child(2) {
            opacity: 0;
        }
        .menu-toggle--active span:nth-child(3) {
            transform: translateY(-8px) rotate(-45deg);
        }

        /* ==================== 下载页 Hero ==================== */
        .hero-download {
            text-align: center;
            padding: 50px 0 20px;
        }

        .hero-download h1 {
            font-size: 2.8rem;
            font-weight: 800;
            background: linear-gradient(to right, #f0f6ff, #8899b4);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            margin-bottom: 10px;
            letter-spacing: -0.5px;
        }

        .hero-download p {
            color: var(--text-secondary);
            font-size: 1.15rem;
            max-width: 620px;
            margin: 0 auto;
        }

        /* 平台选项卡 */
        .platform-badge-row {
            display: flex;
            justify-content: center;
            gap: 16px;
            margin: 36px 0 24px;
            flex-wrap: wrap;
        }

        .platform-tab {
            padding: 10px 28px;
            border-radius: 40px;
            font-weight: 700;
            font-size: 1rem;
            background: transparent;
            border: 1px solid var(--border-soft);
            color: var(--text-secondary);
            cursor: pointer;
            transition: all 0.3s;
            display: flex;
            align-items: center;
            gap: 8px;
        }

        .platform-tab.active {
            background: rgba(12, 230, 181, 0.1);
            border-color: var(--accent-teal);
            color: var(--accent-teal);
            box-shadow: var(--shadow-glow-teal);
        }

        .platform-tab:hover {
            border-color: var(--accent-teal);
            color: var(--accent-teal);
        }

        /* 下载面板布局 */
        .download-panel {
            background: var(--bg-card);
            backdrop-filter: blur(8px);
            border: 1px solid var(--border-soft);
            border-radius: var(--radius-xl);
            overflow: hidden;
            margin-bottom: 50px;
        }

        .panel-content {
            display: none;
            padding: 36px 32px;
        }

        .panel-content.active-panel {
            display: block;
        }

        .download-layout {
            display: flex;
            flex-wrap: wrap;
            gap: 32px;
            align-items: center;
        }

        .download-info-area {
            flex: 1 1 400px;
        }

        .download-info-area h2 {
            font-size: 2rem;
            font-weight: 700;
            color: #f0f6ff;
            margin-bottom: 8px;
        }

        .version-chip {
            display: inline-block;
            background: rgba(12, 230, 181, 0.1);
            border: 1px solid rgba(12, 230, 181, 0.3);
            border-radius: 100px;
            padding: 6px 16px;
            font-size: 0.8rem;
            color: var(--accent-teal);
            margin-bottom: 16px;
            font-weight: 600;
        }

        .download-info-area p {
            color: var(--text-secondary);
            line-height: 1.65;
            margin-bottom: 24px;
            font-size: 0.95rem;
        }

        .download-btn-large {
            display: inline-block;
            background: var(--gradient-hero);
            padding: 14px 34px;
            border-radius: 50px;
            font-weight: 700;
            color: #061018;
            font-size: 1.1rem;
            box-shadow: 0 8px 22px rgba(12, 230, 181, 0.3);
            transition: all 0.3s;
            margin-bottom: 24px;
            text-align: center;
            cursor: pointer;
            border: none;
        }

        .download-btn-large:hover {
            transform: translateY(-3px);
            box-shadow: 0 14px 30px rgba(12, 230, 181, 0.5);
        }

        .spec-table {
            margin-bottom: 20px;
        }

        .spec-row {
            display: flex;
            justify-content: space-between;
            padding: 8px 0;
            border-bottom: 1px solid rgba(255, 255, 255, 0.05);
            font-size: 0.9rem;
            color: var(--text-secondary);
        }

        .spec-row span:first-child {
            font-weight: 600;
            color: #c0d0e0;
        }

        .features-list {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
        }

        .feature-tag {
            background: rgba(12, 230, 181, 0.08);
            border: 1px solid rgba(12, 230, 181, 0.2);
            border-radius: 30px;
            padding: 5px 14px;
            font-size: 0.78rem;
            font-weight: 600;
            color: var(--accent-teal);
            letter-spacing: 0.3px;
        }

        .download-visual {
            flex: 0 0 220px;
            background: linear-gradient(145deg, #0b1420, #040a10);
            border-radius: 24px;
            padding: 28px 20px;
            text-align: center;
            border: 1px solid var(--border-soft);
            box-shadow: 0 0 30px rgba(12, 230, 181, 0.08);
        }

        .os-icon-large {
            font-size: 4rem;
            margin-bottom: 12px;
            filter: drop-shadow(0 0 8px rgba(12, 230, 181, 0.4));
        }

        .terminal-preview {
            background: #03070e;
            border-radius: 12px;
            padding: 14px;
            font-family: 'Fira Code', monospace;
            font-size: 0.75rem;
            color: #b0c0d4;
            text-align: left;
            line-height: 1.7;
        }

        /* ==================== 智能选择引导 ==================== */
        .selector-section {
            margin: 50px 0;
            background: var(--gradient-subtle);
            border-radius: var(--radius-xl);
            padding: 48px 32px;
            text-align: center;
        }

        .selector-title {
            font-size: 2rem;
            font-weight: 700;
            color: #f0f6ff;
            margin-bottom: 12px;
        }

        .selector-sub {
            color: var(--text-secondary);
            margin-bottom: 40px;
            font-size: 1rem;
        }

        .selector-flow {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: center;
            gap: 24px;
        }

        .flow-card {
            background: var(--bg-card);
            border: 1px solid var(--border-soft);
            border-radius: 20px;
            padding: 28px 22px;
            min-width: 200px;
            transition: all 0.3s;
            position: relative;
        }

        .flow-card:hover {
            border-color: var(--accent-teal);
            transform: translateY(-5px);
            box-shadow: 0 12px 28px rgba(0, 0, 0, 0.5);
        }

        .flow-card h4 {
            font-size: 1.4rem;
            margin-bottom: 10px;
            color: #fff;
        }

        .flow-card p {
            font-size: 0.85rem;
            color: var(--text-secondary);
            line-height: 1.6;
        }

        .flow-card .recommend-tag {
            display: inline-block;
            background: var(--accent-teal);
            color: #061018;
            font-size: 0.7rem;
            font-weight: 800;
            padding: 3px 12px;
            border-radius: 20px;
            margin-bottom: 8px;
            letter-spacing: 0.5px;
        }

        .flow-arrow {
            font-size: 2.2rem;
            color: var(--accent-teal);
            flex: 0 0 auto;
            display: none;
        }

        @media (min-width: 769px) {
            .flow-arrow {
                display: block;
            }
        }

        /* ==================== 安装步骤 ==================== */
        .install-flow-section {
            margin: 50px 0;
            text-align: center;
        }

        .flow-heading {
            font-size: 1.8rem;
            font-weight: 700;
            color: #f0f6ff;
            margin-bottom: 32px;
        }

        .steps-grid {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 24px;
        }

        .step-card {
            background: var(--bg-card);
            border: 1px solid var(--border-soft);
            border-radius: 20px;
            padding: 30px 20px;
            flex: 1 1 220px;
            transition: all 0.3s;
        }

        .step-card:hover {
            border-color: var(--accent-teal);
            transform: translateY(-4px);
        }

        .step-num {
            font-size: 2rem;
            font-weight: 800;
            background: var(--gradient-hero);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            display: block;
            margin-bottom: 10px;
        }

        .step-icon {
            font-size: 2.2rem;
            margin: 10px 0;
        }

        .step-card h4 {
            font-size: 1.2rem;
            color: #fff;
            margin-bottom: 8px;
        }

        .step-card p {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.6;
        }

        /* ==================== 内嵌常见问题 ==================== */
        .faq-inline-section {
            margin: 50px 0;
        }

        .faq-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: 20px;
            margin-top: 30px;
        }

        .faq-item {
            background: var(--bg-card);
            border: 1px solid var(--border-soft);
            border-radius: 16px;
            padding: 22px 20px;
            transition: all 0.3s;
        }

        .faq-item:hover {
            border-color: var(--accent-teal);
            background: var(--bg-card-hover);
        }

        .faq-item h4 {
            font-size: 1rem;
            color: #f0f6ff;
            margin-bottom: 10px;
        }

        .faq-item p {
            font-size: 0.85rem;
            color: var(--text-secondary);
            line-height: 1.6;
        }

        /* ==================== CTA 号召区域 ==================== */
        .cta-banner {
            position: relative;
            background: linear-gradient(135deg, #0a1620 0%, #110d28 100%);
            border-radius: var(--radius-xl);
            margin: 50px 0 36px;
            overflow: hidden;
            padding: 56px 0;
        }

        .cta-content {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 26px;
            position: relative;
            z-index: 2;
            padding: 0 32px;
        }

        .cta-text h2 {
            font-size: 1.9rem;
            color: #fff;
            margin-bottom: 10px;
        }

        .cta-text p {
            color: #c0d0e0;
            max-width: 500px;
            font-size: 0.95rem;
            line-height: 1.6;
        }

        .cta-buttons {
            display: flex;
            gap: 14px;
            flex-wrap: wrap;
        }

        .btn-glow {
            background: var(--gradient-hero);
            border: none;
            padding: 14px 36px;
            border-radius: 50px;
            font-weight: 700;
            color: #061018;
            transition: transform 0.2s, box-shadow 0.3s;
            font-size: 1.05rem;
            box-shadow: 0 8px 22px rgba(12, 230, 181, 0.3);
            display: inline-block;
            text-align: center;
        }

        .btn-glow:hover {
            transform: translateY(-2px);
            box-shadow: 0 14px 30px rgba(12, 230, 181, 0.5);
        }

        .btn-ghost-light {
            background: transparent;
            border: 1px solid rgba(255, 255, 255, 0.3);
            padding: 14px 36px;
            border-radius: 50px;
            font-weight: 600;
            color: #fff;
            transition: all 0.3s;
            font-size: 1rem;
            display: inline-block;
        }

        .btn-ghost-light:hover {
            background: rgba(255, 255, 255, 0.08);
            border-color: rgba(255, 255, 255, 0.5);
        }

        .cta-decoration {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
        }

        .cta-dot {
            position: absolute;
            border-radius: 50%;
            opacity: 0.15;
            filter: blur(35px);
        }

        .cta-dot-1 {
            width: 180px;
            height: 180px;
            top: -40px;
            right: -30px;
            background: var(--accent-teal);
        }

        .cta-dot-2 {
            width: 140px;
            height: 140px;
            bottom: -25px;
            left: 8%;
            background: var(--accent-amber);
        }

        .cta-dot-3 {
            width: 90px;
            height: 90px;
            top: 45%;
            left: 58%;
            background: var(--accent-purple);
        }

        /* ==================== 页脚 ==================== */
        footer {
            background: #030a12;
            border-top: 1px solid #1a2a3a;
            padding: 50px 0 24px;
            margin-top: 36px;
        }

        .footer-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
            gap: 36px;
        }

        .footer-col h4 {
            color: #f1f5f9;
            margin-bottom: 16px;
            font-size: 0.95rem;
            font-weight: 700;
        }

        .footer-col p {
            color: var(--text-secondary);
            font-size: 0.82rem;
            line-height: 1.6;
        }

        .footer-col a {
            display: block;
            color: #8899b4;
            font-size: 0.85rem;
            margin-bottom: 7px;
            transition: color 0.2s;
        }

        .footer-col a:hover {
            color: var(--accent-teal);
        }

        .footer-brand {
            font-size: 1.3rem;
            font-weight: 800;
            background: var(--gradient-hero);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            margin-bottom: 6px;
        }

        .footer-bottom {
            text-align: center;
            padding-top: 36px;
            color: #4a5568;
            font-size: 0.75rem;
            border-top: 1px solid #1a2a3a;
            margin-top: 32px;
        }

        /* ==================== 响应式 ==================== */
        @media (max-width: 768px) {
            .container {
                padding: 0 18px;
            }
            .nav-menu {
                display: none;
                flex-direction: column;
                width: 100%;
                background: rgba(6, 13, 23, 0.98);
                backdrop-filter: blur(20px);
                margin-top: 14px;
                padding: 14px 0;
                gap: 10px;
                border-radius: 14px;
            }
            .nav-menu--open {
                display: flex;
            }
            .menu-toggle {
                display: flex;
            }
            .download-layout {
                flex-direction: column;
            }
            .download-visual {
                flex: 0 0 auto;
                width: 100%;
            }
            .hero-download h1 {
                font-size: 2rem;
            }
            .selector-flow {
                flex-direction: column;
            }
            .flow-arrow {
                transform: rotate(90deg);
            }
            .cta-content {
                flex-direction: column;
                text-align: center;
            }
            .footer-grid {
                grid-template-columns: 1fr 1fr;
                gap: 26px;
            }
        }