:root {
      --primary: rgb(14, 165, 233);
      --primary-hover: rgb(2, 132, 199);
      --primary-light: rgba(14, 165, 233, 0.1);
      --dark-bg: #0f172a;
      --light-bg: #f8fafc;
      --text-main: #0f172a;
      --text-muted: #64748b;
      --border-color: #e2e8f0;
      --white: #ffffff;
      --container-width: 1200px;
    }

    * { margin: 0; padding: 0; box-sizing: border-box; }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: var(--text-main);
      background-color: var(--light-bg);
      line-height: 1.6;
    }
    a { color: inherit; text-decoration: none; transition: all 0.3s ease; }
    .container { width: 100%; max-width: var(--container-width); margin: 0 auto; padding: 0 20px; }

    
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 12px 28px;
      border-radius: 8px;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.25s ease;
      border: 1px solid transparent;
    }
    .btn-primary { background-color: var(--primary); color: var(--white); }
    .btn-primary:hover { background-color: var(--primary-hover); }
    .btn-outline { background-color: transparent; border-color: var(--border-color); color: var(--text-main); }
    .btn-outline:hover { background-color: var(--border-color); }

    
    .site-header { background-color: var(--white); border-bottom: 1px solid var(--border-color); position: sticky; top: 0; z-index: 100; height: 72px; }
    .header-container { display: flex; align-items: center; justify-content: space-between; height: 100%; }
    .logo { display: inline-flex; align-items: center; gap: 12px; }
    .logo img { height: 40px; width: auto; object-fit: contain; }
    .logo span { font-size: 18px; font-weight: 800; color: var(--text-main); }
    .desktop-nav { display: flex; align-items: center; gap: 32px; }
    .desktop-nav a { font-size: 15px; font-weight: 500; color: var(--text-muted); }
    .desktop-nav a:hover, .desktop-nav a.active { color: var(--primary); }
    .header-actions { display: flex; align-items: center; gap: 16px; }
    .mobile-menu-toggle { display: none; flex-direction: column; justify-content: space-between; width: 24px; height: 18px; background: transparent; border: none; cursor: pointer; }
    .mobile-menu-toggle span { display: block; height: 2px; width: 100%; background-color: var(--text-main); }

    
    .mobile-drawer-mask { position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; background-color: rgba(15, 23, 42, 0.6); z-index: 101; opacity: 0; visibility: hidden; transition: all 0.3s ease; backdrop-filter: blur(4px); }
    .mobile-drawer { position: fixed; top: 0; left: -320px; width: 300px; height: 100vh; background-color: var(--white); z-index: 102; transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1); display: flex; flex-direction: column; }
    .mobile-drawer.active { left: 0; }
    .mobile-drawer-mask.active { opacity: 1; visibility: visible; }
    .drawer-header { padding: 20px; border-bottom: 1px solid var(--border-color); display: flex; align-items: center; justify-content: space-between; }
    .drawer-close { font-size: 28px; background: transparent; border: none; cursor: pointer; color: var(--text-muted); }
    .drawer-body { flex: 1; padding: 24px; overflow-y: auto; }
    .drawer-nav { display: flex; flex-direction: column; gap: 20px; }
    .drawer-nav a { font-size: 16px; font-weight: 600; color: var(--text-main); padding: 8px 0; border-bottom: 1px solid rgba(0, 0, 0, 0.03); }
    .drawer-footer { padding: 20px; border-top: 1px solid var(--border-color); }

    
    .download-hero { background-color: var(--dark-bg); color: var(--white); padding: 80px 0; text-align: center; }
    .download-hero h1 { font-size: 36px; font-weight: 800; margin-bottom: 16px; }
    .download-hero p { font-size: 18px; color: #94a3b8; max-width: 700px; margin: 0 auto; }

    
    .download-options { padding: 80px 0; }
    .download-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
    .download-card { background: var(--white); border: 1px solid var(--border-color); border-radius: 16px; padding: 40px; text-align: center; display: flex; flex-direction: column; align-items: center; transition: all 0.3s ease; }
    .download-card:hover { transform: translateY(-5px); box-shadow: 0 10px 30px rgba(0,0,0,0.05); border-color: var(--primary); }
    .platform-icon { width: 64px; height: 64px; color: var(--primary); margin-bottom: 24px; display: flex; align-items: center; justify-content: center; }
    .download-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 12px; }
    .download-card p { font-size: 14px; color: var(--text-muted); margin-bottom: 30px; flex: 1; }

    
    .guide-section { padding: 80px 0; background-color: var(--white); border-top: 1px solid var(--border-color); border-bottom: 1px solid var(--border-color); }
    .guide-title { text-align: center; font-size: 28px; font-weight: 800; margin-bottom: 50px; }
    .guide-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 30px; }
    .guide-item { text-align: center; position: relative; }
    .guide-step { width: 40px; height: 40px; border-radius: 50%; background-color: var(--primary-light); color: var(--primary); display: flex; align-items: center; justify-content: center; font-weight: 800; margin: 0 auto 20px; font-size: 16px; }
    .guide-item h4 { font-size: 16px; font-weight: 700; margin-bottom: 10px; }
    .guide-item p { font-size: 13px; color: var(--text-muted); }

    
    .site-footer { background-color: #0b0f19; color: #94a3b8; padding: 80px 0 40px; font-size: 14px; border-top: 1px solid #1e293b; }
    .footer-container { display: grid; grid-template-columns: 2fr 1fr 1fr 2fr; gap: 40px; margin-bottom: 60px; }
    .footer-brand .logo { margin-bottom: 20px; }
    .footer-brand .logo span { color: var(--white); }
    .brand-desc { line-height: 1.7; margin-bottom: 20px; }
    .footer-container h4 { color: var(--white); font-size: 16px; font-weight: 700; margin-bottom: 24px; }
    .footer-container ul { list-style: none; }
    .footer-container ul li { margin-bottom: 12px; }
    .footer-container ul a:hover { color: var(--primary); }
    .risk-warning { font-size: 12px; line-height: 1.8; color: #64748b; }
    .footer-bottom { border-top: 1px solid #1e293b; padding-top: 30px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 16px; font-size: 12px; }

    @media (max-width: 768px) {
      .desktop-nav { display: none; }
      .mobile-menu-toggle { display: flex; }
      .download-grid { grid-template-columns: 1fr; }
      .guide-grid { grid-template-columns: 1fr; }
    }