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

    body {
      font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Helvetica, sans-serif;
      background-color: #ffffff;
      color: #111111;
      line-height: 1.5;
      scroll-behavior: smooth;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    .header {
      background-color: #ffffff;
      border-bottom: 1px solid #e5e7eb;
      position: sticky;
      top: 0;
      z-index: 50;
    }

    .nav {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      padding: 18px 0;
    }

    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      background: linear-gradient(135deg, #25D366, #128C7E);
      -webkit-background-clip: text;
      background-clip: text;
      color: transparent;
      text-decoration: none;
    }

    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      list-style: none;
    }

    .nav-links a {
      text-decoration: none;
      font-weight: 500;
      color: #1f2937;
      transition: color 0.2s;
      font-size: 1rem;
    }

    .nav-links a:hover {
      color: #25D366;
    }

    .nav-links .active {
      color: #128C7E;
      font-weight: 600;
    }

    .btn-primary {
      display: inline-block;
      background-color: #25D366;
      color: white;
      font-weight: 600;
      padding: 12px 32px;
      border-radius: 40px;
      text-decoration: none;
      transition: background 0.2s, transform 0.1s;
      border: none;
      font-size: 1rem;
      cursor: pointer;
    }

    .btn-primary:hover {
      background-color: #128C7E;
    }

    .btn-secondary {
      background: white;
      border: 1px solid #cfdde6;
      padding: 12px 28px;
      border-radius: 40px;
      font-weight: 600;
      text-decoration: none;
      color: #1f2a3e;
      transition: 0.2s;
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }

    .btn-secondary:hover {
      border-color: #25D366;
      background: #f0fdf4;
    }

    .download-hero {
      padding: 80px 0 48px;
      background: linear-gradient(135deg, #f0fdf4 0%, #ffffff 80%);
    }

    .download-header {
      text-align: center;
      max-width: 720px;
      margin: 0 auto 48px;
    }

    .download-header h1 {
      font-size: 3rem;
      font-weight: 800;
      background: linear-gradient(135deg, #075e54, #128C7E);
      -webkit-background-clip: text;
      background-clip: text;
      color: transparent;
      margin-bottom: 20px;
    }

    .download-header p {
      font-size: 1.2rem;
      color: #374151;
    }

    .download-cards {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 40px;
      margin: 48px 0 64px;
    }

    .card {
      background: #ffffff;
      border-radius: 40px;
      box-shadow: 0 20px 35px -12px rgba(0, 0, 0, 0.1);
      padding: 40px 32px;
      flex: 1;
      min-width: 260px;
      max-width: 360px;
      text-align: center;
      transition: transform 0.2s, box-shadow 0.2s;
      border: 1px solid #e9f0e6;
    }

    .card:hover {
      transform: translateY(-6px);
      box-shadow: 0 30px 40px -16px rgba(0, 0, 0, 0.15);
      border-color: #c8e6d9;
    }

    .card-icon {
      font-size: 3.8rem;
      margin-bottom: 20px;
    }

    .card h2 {
      font-size: 1.8rem;
      font-weight: 700;
      margin-bottom: 12px;
    }

    .card p {
      color: #4b5563;
      margin-bottom: 28px;
      font-size: 0.95rem;
    }

    .download-btn {
      background-color: #25D366;
      color: white;
      border: none;
      padding: 12px 24px;
      width: 100%;
      font-weight: 600;
      border-radius: 40px;
      font-size: 1rem;
      cursor: pointer;
      transition: background 0.2s;
      text-decoration: none;
      display: inline-block;
    }

    .download-btn:hover {
      background-color: #128C7E;
    }

    .system-requirements {
      background: #f9fafb;
      border-radius: 32px;
      padding: 32px;
      margin: 32px 0 48px;
    }

    .system-requirements h3 {
      font-size: 1.4rem;
      margin-bottom: 20px;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .req-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
      gap: 24px;
    }

    .req-item {
      background: white;
      padding: 18px;
      border-radius: 24px;
      border-left: 4px solid #25D366;
    }

    .req-item strong {
      display: block;
      margin-bottom: 8px;
      color: #075e54;
    }

    .other-platforms {
      text-align: center;
      margin: 40px 0 60px;
      padding: 32px;
      background: #eef5f0;
      border-radius: 48px;
    }

    .badge-group {
      display: flex;
      justify-content: center;
      flex-wrap: wrap;
      gap: 16px;
      margin-top: 24px;
    }

    .badge {
      background: white;
      padding: 8px 20px;
      border-radius: 60px;
      font-weight: 500;
      color: #1f2a3e;
      text-decoration: none;
      border: 1px solid #cbd5e1;
    }

    .footer {
      border-top: 1px solid #eaeef3;
      padding: 48px 0 32px;
      background: #fafcff;
    }

    .footer-grid {
      display: flex;
      flex-wrap: wrap;
      justify-content: space-between;
      gap: 32px;
      margin-bottom: 40px;
    }

    .footer-col {
      min-width: 140px;
    }

    .footer-col h4 {
      font-weight: 600;
      margin-bottom: 18px;
      color: #111827;
    }

    .footer-col ul {
      list-style: none;
    }

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

    .footer-col a {
      text-decoration: none;
      color: #4b5563;
      font-size: 0.9rem;
    }

    .footer-col a:hover {
      color: #128C7E;
    }

    .copyright {
      text-align: center;
      padding-top: 28px;
      border-top: 1px solid #e5e7eb;
      font-size: 0.8rem;
      color: #6c757d;
    }

    @media (max-width: 768px) {
      .nav {
        flex-direction: column;
        gap: 16px;
      }
      .nav-links {
        flex-wrap: wrap;
        justify-content: center;
        gap: 20px;
      }
      .download-header h1 {
        font-size: 2.2rem;
      }
      .card {
        max-width: 100%;
      }
    }