:root {
            --iuiyl-primary: #0052CC;
            --iuiyl-primary-light: #4C9AFF;
            --iuiyl-accent: #FF4D4F;
            --iuiyl-dark: #172B4D;
            --iuiyl-text: #42526E;
            --iuiyl-bg-light: #F4F5F7;
            --iuiyl-white: #FFFFFF;
            --iuiyl-gap: 8px;
            --iuiyl-radius: 16px;
            --iuiyl-container-width: 1320px;
            --iuiyl-transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }

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

        body {
            font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
            color: var(--iuiyl-text);
            line-height: 1.8;
            background-color: var(--iuiyl-white);
            overflow-x: hidden;
            word-break: break-word;
        }

        /* Layout Helpers */
        .iuiyl-container {
            max-width: var(--iuiyl-container-width);
            margin: 0 auto;
            padding: 0 calc(var(--iuiyl-gap) * 3);
        }

        .iuiyl-flex {
            display: flex;
            flex-wrap: wrap;
        }

        .iuiyl-grid {
            display: grid;
            gap: calc(var(--iuiyl-gap) * 4);
        }

        /* Navigation */
        .iuiyl-nav-wrapper {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 1000;
            background: rgba(255, 255, 255, 0.85);
            backdrop-filter: blur(15px);
            border-bottom: 1px solid rgba(0, 0, 0, 0.05);
            box-shadow: 0 4px 30px rgba(0, 0, 0, 0.03);
        }

        .iuiyl-nav-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 80px;
            max-width: var(--iuiyl-container-width);
            margin: 0 auto;
            padding: 0 calc(var(--iuiyl-gap) * 3);
        }

        .iuiyl-logo {
            flex-shrink: 0;
        }

        .iuiyl-logo img {
            height: 40px;
            width: auto;
            display: block;
        }

        .iuiyl-menu {
            display: flex;
            list-style: none;
            gap: calc(var(--iuiyl-gap) * 3);
        }

        .iuiyl-menu-item a {
            text-decoration: none;
            color: var(--iuiyl-dark);
            font-weight: 500;
            font-size: 15px;
            transition: var(--iuiyl-transition);
            padding: calc(var(--iuiyl-gap) * 1) calc(var(--iuiyl-gap) * 2);
            border-radius: 8px;
        }

        .iuiyl-menu-item a:hover {
            color: var(--iuiyl-primary);
            background: rgba(0, 82, 204, 0.05);
        }

        .iuiyl-menu-item a.iuiyl-active {
            color: var(--iuiyl-primary);
            background: rgba(0, 82, 204, 0.1);
        }

        /* Hero Download Section */
        .iuiyl-hero {
            padding: 160px 0 80px;
            background: radial-gradient(circle at top right, #f0f7ff 0%, #ffffff 50%);
            position: relative;
            overflow: hidden;
        }

        .iuiyl-hero-content {
            flex: 1;
            min-width: 320px;
            padding-right: 40px;
        }

        .iuiyl-hero-title {
            font-size: clamp(2.5rem, 5vw + 1rem, 4rem);
            font-weight: 800;
            color: var(--iuiyl-dark);
            line-height: 1.1;
            margin-bottom: calc(var(--iuiyl-gap) * 3);
            word-break: keep-all;
        }

        .iuiyl-hero-subtitle {
            font-size: clamp(1rem, 2vw + 0.5rem, 1.25rem);
            color: var(--iuiyl-text);
            max-width: 600px;
            margin-bottom: calc(var(--iuiyl-gap) * 5);
        }

        .iuiyl-hero-image {
            flex: 1.2;
            min-width: 320px;
            position: relative;
        }

        .iuiyl-portal-card {
            background: var(--iuiyl-white);
            border-radius: var(--iuiyl-radius);
            box-shadow: 0 32px 64px rgba(0, 82, 204, 0.12);
            padding: calc(var(--iuiyl-gap) * 2);
            transform: perspective(1000px) rotateY(-5deg) rotateX(2deg);
            transition: var(--iuiyl-transition);
        }

        .iuiyl-portal-card:hover {
            transform: perspective(1000px) rotateY(0deg) rotateX(0deg);
        }

        .iuiyl-portal-card img {
            width: 100%;
            height: auto;
            border-radius: calc(var(--iuiyl-radius) - 4px);
            display: block;
        }

        /* Download Button Group */
        .iuiyl-download-group {
            display: flex;
            flex-wrap: wrap;
            gap: calc(var(--iuiyl-gap) * 2);
        }

        .iuiyl-btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 16px 40px;
            border-radius: 50px;
            font-size: 18px;
            font-weight: 600;
            text-decoration: none;
            transition: var(--iuiyl-transition);
            cursor: pointer;
        }

        .iuiyl-btn-primary {
            background: linear-gradient(135deg, var(--iuiyl-primary) 0%, var(--iuiyl-primary-light) 100%);
            color: var(--iuiyl-white);
            box-shadow: 0 10px 20px rgba(0, 82, 204, 0.2);
        }

        .iuiyl-btn-primary:hover {
            transform: translateY(-3px);
            box-shadow: 0 15px 30px rgba(0, 82, 204, 0.3);
        }

        /* Journey Section */
        .iuiyl-journey-section {
            padding: 96px 0;
            background: #fafbfc;
        }

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

        .iuiyl-section-title {
            font-size: clamp(2rem, 3vw, 2.5rem);
            color: var(--iuiyl-dark);
            margin-bottom: 16px;
        }

        .iuiyl-step-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 32px;
        }

        .iuiyl-step-card {
            background: var(--iuiyl-white);
            padding: 40px;
            border-radius: var(--iuiyl-radius);
            border: 1px solid rgba(0, 0, 0, 0.05);
            transition: var(--iuiyl-transition);
            position: relative;
        }

        .iuiyl-step-card:hover {
            border-color: var(--iuiyl-primary);
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.04);
        }

        .iuiyl-step-number {
            font-size: 48px;
            font-weight: 900;
            color: rgba(0, 82, 204, 0.1);
            position: absolute;
            top: 20px;
            right: 30px;
        }

        .iuiyl-step-title {
            font-size: 20px;
            font-weight: 700;
            color: var(--iuiyl-dark);
            margin-bottom: 16px;
        }

        /* Platform Section */
        .iuiyl-platform-section {
            padding: 96px 0;
        }

        .iuiyl-platform-box {
            background: var(--iuiyl-dark);
            border-radius: 24px;
            padding: 64px;
            color: var(--iuiyl-white);
            align-items: center;
            gap: 48px;
        }

        .iuiyl-platform-text {
            flex: 1;
            min-width: 300px;
        }

        .iuiyl-platform-img {
            flex: 1;
            min-width: 300px;
        }

        .iuiyl-platform-img img {
            width: 100%;
            height: auto;
            filter: drop-shadow(0 20px 40px rgba(0,0,0,0.3));
        }

        /* Features/Comparison Section */
        .iuiyl-pro-section {
            padding: 96px 0;
        }

        .iuiyl-pro-layout {
            display: flex;
            align-items: center;
            gap: 64px;
            flex-direction: row-reverse;
        }

        .iuiyl-pro-img {
            flex: 1.2;
            min-width: 320px;
        }

        .iuiyl-pro-img img {
            width: 100%;
            border-radius: var(--iuiyl-radius);
            box-shadow: 0 40px 80px rgba(0, 0, 0, 0.08);
        }

        .iuiyl-pro-content {
            flex: 1;
            min-width: 320px;
        }

        .iuiyl-pro-list {
            list-style: none;
            margin-top: 32px;
        }

        .iuiyl-pro-item {
            margin-bottom: 24px;
            padding-left: 32px;
            position: relative;
        }

        .iuiyl-pro-item::before {
            content: "✓";
            position: absolute;
            left: 0;
            color: var(--iuiyl-primary);
            font-weight: bold;
            font-size: 20px;
        }

        /* Footer */
        .iuiyl-footer {
            background: #091E42;
            color: rgba(255, 255, 255, 0.7);
            padding: 80px 0 40px;
        }

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

        .iuiyl-footer-brand {
            grid-column: span 2;
        }

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

        .iuiyl-footer-link-group h4 {
            color: var(--iuiyl-white);
            margin-bottom: 24px;
            font-size: 16px;
        }

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

        .iuiyl-footer-link-group li {
            margin-bottom: 12px;
        }

        .iuiyl-footer-link-group a {
            color: inherit;
            text-decoration: none;
            transition: var(--iuiyl-transition);
        }

        .iuiyl-footer-link-group a:hover {
            color: var(--iuiyl-white);
        }

        .iuiyl-footer-bottom {
            padding-top: 40px;
            border-top: 1px solid rgba(255, 255, 255, 0.1);
            text-align: center;
            font-size: 14px;
        }

        /* Responsive */
        @media (max-width: 1024px) {
            .iuiyl-hero {
                padding: 120px 0 60px;
            }
            .iuiyl-platform-box {
                padding: 40px;
            }
        }

        @media (max-width: 768px) {
            .iuiyl-nav-container {
                height: 60px;
            }
            .iuiyl-menu {
                display: none; /* In a real project, add a hamburger menu */
            }
            .iuiyl-flex {
                flex-direction: column;
            }
            .iuiyl-hero-content {
                padding-right: 0;
                margin-bottom: 48px;
                text-align: center;
            }
            .iuiyl-hero-image {
                flex: none;
                width: 100%;
            }
            .iuiyl-download-group {
                justify-content: center;
            }
            .iuiyl-platform-box, .iuiyl-pro-layout {
                flex-direction: column;
                text-align: center;
            }
            .iuiyl-footer-brand {
                grid-column: span 1;
            }
        }