:root {
      --primary-color: #1D7BFF;
      --secondary-color: #00D2FF;
      --dark-color: rgb(35,39,47);
      --light-color: #F5F7FA;
      --silver-color: #E2E8F0;
      --text-main: #333333;
      --text-muted: #666666;
      --border-color: #E2E8F0;
      --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    }

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

    body {
      font-family: var(--font-base);
      color: var(--text-main);
      background-color: #FFFFFF;
      line-height: 1.6;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: all 0.3s ease;
    }

    
    .header {
      background-color: var(--dark-color);
      border-bottom: 1px solid rgba(255, 255, 255, 0.1);
      position: sticky;
      top: 0;
      z-index: 1000;
    }

    .header-container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 15px 20px;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .logo {
      display: inline-flex;
      align-items: center;
      gap: 12px;
    }

    .logo img {
      display: block;
      height: 40px;
      width: auto;
      max-width: 160px;
      object-fit: contain;
      flex-shrink: 0;
    }

    .logo span {
      display: inline-block;
      font-size: 20px;
      font-weight: 800;
      line-height: 1;
      color: #FFFFFF;
      white-space: nowrap;
    }

    .nav-desktop {
      display: flex;
      gap: 24px;
    }

    .nav-desktop a {
      color: rgba(255, 255, 255, 0.8);
      font-weight: 500;
      font-size: 15px;
    }

    .nav-desktop a:hover {
      color: var(--secondary-color);
    }

    .menu-toggle {
      display: none;
      background: none;
      border: none;
      color: #FFFFFF;
      font-size: 24px;
      cursor: pointer;
    }

    
    .mobile-drawer {
      position: fixed;
      top: 0;
      left: -300px;
      width: 300px;
      height: 100%;
      background-color: var(--dark-color);
      z-index: 1100;
      transition: left 0.3s ease;
      display: flex;
      flex-direction: column;
      padding: 20px;
    }

    .mobile-drawer.active {
      left: 0;
    }

    .drawer-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      margin-bottom: 40px;
      border-bottom: 1px solid rgba(255,255,255,0.1);
      padding-bottom: 15px;
    }

    .drawer-close {
      background: none;
      border: none;
      color: #FFFFFF;
      font-size: 28px;
      cursor: pointer;
    }

    .drawer-body {
      display: flex;
      flex-direction: column;
      gap: 20px;
    }

    .drawer-body a {
      color: rgba(255,255,255,0.9);
      font-size: 18px;
      font-weight: 500;
      padding: 8px 0;
    }

    .drawer-body a:hover {
      color: var(--secondary-color);
    }

    .drawer-overlay {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(0,0,0,0.5);
      z-index: 1050;
      display: none;
    }

    .drawer-overlay.active {
      display: block;
    }

    
    .download-hero {
      background: linear-gradient(135deg, var(--dark-color) 0%, #111622 100%);
      color: #FFFFFF;
      text-align: center;
      padding: 80px 20px;
    }

    .download-hero h1 {
      font-size: 38px;
      margin-bottom: 15px;
    }

    .download-hero p {
      color: #A0AEC0;
      font-size: 18px;
      max-width: 600px;
      margin: 0 auto;
    }

    .platform-section {
      max-width: 1200px;
      margin: 60px auto;
      padding: 0 20px;
    }

    .platform-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: 40px;
    }

    .platform-card {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: 12px;
      padding: 40px 30px;
      text-align: center;
      transition: all 0.3s ease;
    }

    .platform-card:hover {
      transform: translateY(-5px);
      box-shadow: 0 10px 20px rgba(0,0,0,0.05);
      border-color: var(--primary-color);
    }

    .platform-icon {
      font-size: 50px;
      margin-bottom: 24px;
      color: var(--primary-color);
    }

    .platform-card h3 {
      font-size: 22px;
      color: var(--dark-color);
      margin-bottom: 12px;
    }

    .platform-card p {
      color: var(--text-muted);
      font-size: 14px;
      margin-bottom: 30px;
      line-height: 1.6;
    }

    .btn-download {
      display: inline-block;
      width: 100%;
      background-color: var(--primary-color);
      color: #FFFFFF;
      padding: 12px 0;
      border-radius: 6px;
      font-weight: 600;
      text-align: center;
    }

    .btn-download:hover {
      background-color: #0062E3;
    }

    
    .guide-section {
      background-color: var(--light-color);
      padding: 80px 20px;
    }

    .guide-container {
      max-width: 800px;
      margin: 0 auto;
    }

    .guide-title {
      text-align: center;
      margin-bottom: 50px;
    }

    .guide-title h2 {
      font-size: 28px;
      color: var(--dark-color);
    }

    .step-item {
      display: flex;
      gap: 24px;
      margin-bottom: 45px;
    }

    .step-item:last-child {
      margin-bottom: 0;
    }

    .step-num {
      width: 44px;
      height: 44px;
      background-color: var(--primary-color);
      color: #FFFFFF;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 18px;
      flex-shrink: 0;
    }

    .step-content h3 {
      font-size: 18px;
      color: var(--dark-color);
      margin-bottom: 10px;
    }

    .step-content p {
      color: var(--text-muted);
      font-size: 14px;
      line-height: 1.6;
    }

    
    .footer {
      background-color: #111622;
      color: #A0AEC0;
      font-size: 14px;
      border-top: 1px solid rgba(255,255,255,0.05);
    }

    .footer-container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 60px 20px;
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
    }

    .footer-brand p {
      margin-top: 15px;
      line-height: 1.6;
    }

    .footer h4 {
      color: #FFFFFF;
      margin-bottom: 20px;
      font-size: 16px;
    }

    .footer ul {
      list-style: none;
    }

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

    .footer ul li a:hover {
      color: #FFFFFF;
    }

    .footer-bottom {
      border-top: 1px solid rgba(255,255,255,0.05);
      padding: 30px 20px;
      text-align: center;
    }

    
    @media (max-width: 768px) {
      .nav-desktop {
        display: none;
      }
      .menu-toggle {
        display: block;
      }
      .step-item {
        flex-direction: column;
        gap: 15px;
      }
      .footer-container {
        grid-template-columns: 1fr;
      }
    }