:root {
            --hdsq1-primary: #1A73E8;
            --hdsq1-secondary: #EA4335;
            --hdsq1-tertiary: #FBBC05;
            --hdsq1-success: #34A853;
            --hdsq1-text: #202124;
            --hdsq1-text-light: #5f6368;
            --hdsq1-bg: #ffffff;
            --hdsq1-bg-alt: #f8f9fa;
            --hdsq1-container-width: 1400px;
            --hdsq1-nav-height: 72px;
            --hdsq1-radius: 16px;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            -webkit-font-smoothing: antialiased;
        }

        body {
            font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, -apple-system, sans-serif;
            color: var(--hdsq1-text);
            background-color: var(--hdsq1-bg);
            line-height: 1.7;
            overflow-x: hidden;
            word-break: keep-all;
        }

        /* Typography */
        h1, h2, h3 {
            line-height: 1.2;
            word-break: keep-all;
            white-space: normal;
        }

        .hdsq1-fluid-h1 { font-size: clamp(2.5rem, 5vw + 1rem, 4.5rem); font-weight: 800; letter-spacing: -0.02em; }
        .hdsq1-fluid-h2 { font-size: clamp(1.8rem, 3vw + 0.5rem, 2.8rem); font-weight: 700; }
        .hdsq1-fluid-p { font-size: clamp(1rem, 1vw + 0.5rem, 1.25rem); color: var(--hdsq1-text-light); }

        /* Navigation */
        .hdsq1-navbar {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: var(--hdsq1-nav-height);
            z-index: 1000;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
            background: transparent;
        }

        .hdsq1-navbar.hdsq1-scrolled {
            background: rgba(255, 255, 255, 0.8);
            backdrop-filter: blur(20px);
            box-shadow: 0 4px 30px rgba(0, 0, 0, 0.05);
            border-bottom: 1px solid rgba(255, 255, 255, 0.3);
        }

        .hdsq1-nav-container {
            width: 100%;
            max-width: var(--hdsq1-container-width);
            padding: 0 24px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
        }

        .hdsq1-logo {
            flex: 0 0 auto;
            min-width: 0;
        }

        .hdsq1-logo img {
            height: 32px;
            display: block;
        }

        .hdsq1-menu {
            display: flex;
            list-style: none;
            gap: 8px;
            flex-wrap: wrap;
            min-width: 0;
        }

        .hdsq1-menu-item a {
            text-decoration: none;
            color: var(--hdsq1-text-light);
            font-size: 0.95rem;
            font-weight: 500;
            padding: 8px 16px;
            border-radius: 30px;
            transition: all 0.3s ease;
        }

        .hdsq1-menu-item a:hover {
            background: rgba(26, 115, 232, 0.05);
            color: var(--hdsq1-primary);
        }

        .hdsq1-menu-item a.active {
            background: var(--hdsq1-primary);
            color: #fff;
        }

        /* Hero Section - Asymmetric Stack */
        .hdsq1-hero {
            position: relative;
            padding-top: calc(var(--hdsq1-nav-height) + 64px);
            padding-bottom: 96px;
            overflow: hidden;
            display: flex;
            flex-direction: column;
            align-items: center;
            text-align: center;
        }

        .hdsq1-liquid-bg {
            position: absolute;
            top: -20%;
            left: -10%;
            width: 120%;
            height: 120%;
            z-index: -1;
            background: radial-gradient(circle at 10% 20%, rgba(66, 133, 244, 0.08) 0%, transparent 40%),
                        radial-gradient(circle at 90% 80%, rgba(52, 168, 83, 0.08) 0%, transparent 40%),
                        radial-gradient(circle at 50% 50%, rgba(251, 188, 5, 0.05) 0%, transparent 60%);
            filter: blur(80px);
        }

        .hdsq1-hero-content {
            max-width: 900px;
            padding: 0 24px;
            margin-bottom: 48px;
            word-break: break-word;
        }

        .hdsq1-hero-title {
            margin-bottom: 24px;
            color: var(--hdsq1-text);
            background: linear-gradient(135deg, #202124 0%, #1A73E8 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .hdsq1-hero-subtitle {
            margin-bottom: 40px;
            max-width: 700px;
            margin-left: auto;
            margin-right: auto;
        }

        .hdsq1-download-card {
            background: #fff;
            padding: 48px;
            border-radius: var(--hdsq1-radius);
            box-shadow: 0 20px 80px rgba(0, 0, 0, 0.08);
            display: inline-flex;
            flex-direction: column;
            align-items: center;
            gap: 24px;
            border: 1px solid rgba(0, 0, 0, 0.03);
            max-width: 100%;
            min-width: 0;
        }

        .hdsq1-btn-download {
            background: var(--hdsq1-primary);
            color: #fff;
            padding: 18px 48px;
            border-radius: 50px;
            font-size: 1.25rem;
            font-weight: 600;
            text-decoration: none;
            display: inline-block;
            box-shadow: 0 8px 25px rgba(26, 115, 232, 0.3);
            transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
            animation: hdsq1-breathing 3s ease-in-out infinite;
        }

        @keyframes hdsq1-breathing {
            0% { transform: scale(1); box-shadow: 0 8px 25px rgba(26, 115, 232, 0.3); }
            50% { transform: scale(1.03); box-shadow: 0 12px 35px rgba(26, 115, 232, 0.4); }
            100% { transform: scale(1); box-shadow: 0 8px 25px rgba(26, 115, 232, 0.3); }
        }

        .hdsq1-btn-download:hover {
            transform: translateY(-3px) scale(1.05);
            background: #1557b0;
        }

        .hdsq1-hero-image-wrap {
            width: 100%;
            max-width: 1100px;
            margin: 64px auto 0;
            padding: 0 24px;
        }

        .hdsq1-hero-image {
            width: 100%;
            height: auto;
            border-radius: var(--hdsq1-radius);
            box-shadow: 0 30px 100px rgba(0,0,0,0.12);
            object-fit: cover;
        }

        /* Section: OS Support - Asymmetric Grid */
        .hdsq1-section-os {
            padding: 96px 0;
            background: var(--hdsq1-bg-alt);
        }

        .hdsq1-container {
            max-width: var(--hdsq1-container-width);
            margin: 0 auto;
            padding: 0 24px;
        }

        .hdsq1-grid-os {
            display: flex;
            flex-wrap: wrap;
            gap: 48px;
            align-items: center;
        }

        .hdsq1-col-text {
            flex: 1 1 400px;
            min-width: 0;
        }

        .hdsq1-col-img {
            flex: 1 1 500px;
            min-width: 0;
        }

        .hdsq1-os-list {
            list-style: none;
            margin-top: 32px;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
            gap: 16px;
        }

        .hdsq1-os-item {
            background: #fff;
            padding: 16px 24px;
            border-radius: 12px;
            font-weight: 500;
            display: flex;
            align-items: center;
            gap: 12px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.03);
            border: 1px solid rgba(0,0,0,0.02);
            transition: transform 0.3s ease;
        }

        .hdsq1-os-item:hover {
            transform: translateY(-4px);
            border-color: var(--hdsq1-primary);
        }

        .hdsq1-img-responsive {
            width: 100%;
            height: auto;
            border-radius: var(--hdsq1-radius);
            box-shadow: 0 10px 40px rgba(0,0,0,0.08);
        }

        /* Section: Guide - Vertical Timeline Flow */
        .hdsq1-section-guide {
            padding: 120px 0;
            position: relative;
        }

        .hdsq1-guide-header {
            text-align: center;
            max-width: 800px;
            margin: 0 auto 64px;
        }

        .hdsq1-guide-wrapper {
            display: flex;
            flex-wrap: wrap;
            gap: 64px;
            flex-direction: row-reverse;
            align-items: flex-start;
        }

        .hdsq1-guide-steps {
            flex: 1 1 450px;
            min-width: 0;
        }

        .hdsq1-step-card {
            padding: 32px;
            margin-bottom: 24px;
            background: #fff;
            border-radius: var(--hdsq1-radius);
            border-left: 6px solid var(--hdsq1-tertiary);
            box-shadow: 0 4px 20px rgba(0,0,0,0.04);
            transition: all 0.3s ease;
        }

        .hdsq1-step-card:nth-child(2) { border-left-color: var(--hdsq1-secondary); }
        .hdsq1-step-card:nth-child(3) { border-left-color: var(--hdsq1-primary); }

        .hdsq1-step-card:hover {
            transform: translateX(10px);
            box-shadow: 0 10px 30px rgba(0,0,0,0.08);
        }

        .hdsq1-step-num {
            font-size: 0.85rem;
            font-weight: 800;
            color: var(--hdsq1-text-light);
            text-transform: uppercase;
            margin-bottom: 8px;
            display: block;
        }

        .hdsq1-step-title {
            font-size: 1.4rem;
            margin-bottom: 12px;
            color: var(--hdsq1-text);
        }

        /* Footer */
        .hdsq1-footer {
            background: #f1f3f4;
            padding: 80px 0 40px;
            border-top: 1px solid rgba(0,0,0,0.05);
        }

        .hdsq1-footer-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 48px;
            margin-bottom: 64px;
        }

        .hdsq1-footer-brand h3 {
            font-size: 1.5rem;
            font-weight: 800;
            margin-bottom: 16px;
            color: var(--hdsq1-primary);
        }

        .hdsq1-footer-links h4 {
            margin-bottom: 24px;
            font-size: 1.1rem;
        }

        .hdsq1-footer-links ul {
            list-style: none;
        }

        .hdsq1-footer-links li {
            margin-bottom: 12px;
        }

        .hdsq1-footer-links a {
            text-decoration: none;
            color: var(--hdsq1-text-light);
            transition: color 0.3s;
        }

        .hdsq1-footer-links a:hover {
            color: var(--hdsq1-primary);
        }

        .hdsq1-footer-bottom {
            padding-top: 32px;
            border-top: 1px solid rgba(0,0,0,0.05);
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 24px;
            color: var(--hdsq1-text-light);
            font-size: 0.9rem;
        }

        /* Responsive Breakpoints */
        @media (max-width: 992px) {
            .hdsq1-nav-container { justify-content: center; padding: 12px; }
            .hdsq1-logo { margin-bottom: 12px; width: 100%; text-align: center; }
            .hdsq1-menu { justify-content: center; }
            .hdsq1-navbar { height: auto; padding: 12px 0; }
            .hdsq1-hero { padding-top: 140px; }
        }

        @media (max-width: 768px) {
            .hdsq1-menu-item a { font-size: 0.85rem; padding: 6px 12px; }
            .hdsq1-col-text, .hdsq1-col-img, .hdsq1-guide-steps { flex: 1 1 100%; }
            .hdsq1-hero-content { padding: 0 16px; }
            .hdsq1-download-card { padding: 32px 24px; }
            .hdsq1-fluid-h1 { font-size: 2.2rem; }
            .hdsq1-fluid-h2 { font-size: 1.8rem; }
            .hdsq1-section-os, .hdsq1-section-guide { padding: 64px 0; }
            .hdsq1-footer-bottom { justify-content: center; text-align: center; }
        }

        /* Scroll Animation Utility */
        .hdsq1-reveal {
            opacity: 1; /* Content defaults to visible */
            transform: translateY(0);
            transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
        }

        .hdsq1-reveal.hdsq1-active {
            transform: translateY(-20px);
        }