<style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', 'Noto Sans', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      background: #f8fafc;
      color: #1e293b;
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    .card, .version-download-card, .faq-card, .step-guide-card {
      background: #ffffff;
      border-radius: 20px;
      box-shadow: 0 10px 30px -8px rgba(0, 0, 0, 0.04), 0 4px 12px rgba(0, 0, 0, 0.02);
      border: 1px solid rgba(226, 232, 240, 0.8);
      transition: all 0.3s ease;
    }
    .card:hover, .version-download-card:hover {
      transform: translateY(-4px);
      box-shadow: 0 25px 40px -12px rgba(0, 102, 204, 0.1);
      border-color: rgba(0, 102, 204, 0.12);
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      background: linear-gradient(135deg, #0066cc 0%, #0052a3 100%);
      color: #ffffff;
      font-weight: 600;
      padding: 13px 30px;
      border-radius: 40px;
      transition: all 0.25s;
      letter-spacing: 0.3px;
      box-shadow: 0 8px 20px rgba(0, 102, 204, 0.25);
      border: none;
      cursor: pointer;
      font-size: 1rem;
    }
    .btn:hover {
      background: linear-gradient(135deg, #0077e6 0%, #004b8c 100%);
      box-shadow: 0 14px 28px rgba(0, 102, 204, 0.35);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid #0066cc;
      color: #0066cc;
      box-shadow: none;
      font-weight: 600;
    }
    .btn-outline:hover {
      background: #0066cc;
      color: #ffffff;
    }
    h1, h2, h3 {
      font-weight: 650;
      letter-spacing: -0.3px;
    }
    h1 {
      font-size: clamp(2rem, 4.5vw, 3rem);
      line-height: 1.2;
    }
    h2 {
      font-size: clamp(1.6rem, 3.5vw, 2.2rem);
      margin-bottom: 1.5rem;
    }
    h3 {
      font-size: 1.25rem;
    }
    .section-title {
      text-align: center;
      margin-bottom: 2.5rem;
      color: #0f172a;
    }
    header {
      background: rgba(255, 255, 255, 0.85);
      backdrop-filter: blur(18px);
      position: sticky;
      top: 0;
      z-index: 50;
      border-bottom: 1px solid rgba(0, 102, 204, 0.06);
    }
    .nav-bar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 16px 0;
      flex-wrap: wrap;
      gap: 18px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 1.7rem;
      color: #0066cc;
    }
    .logo-icon {
      background: linear-gradient(135deg, #0066cc, #004b8c);
      color: #fff;
      width: 40px;
      height: 40px;
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.4rem;
      font-weight: 700;
      box-shadow: 0 4px 10px rgba(0,102,204,0.3);
    }
    .nav-links {
      display: flex;
      gap: 24px;
      align-items: center;
      flex-wrap: wrap;
    }
    .nav-links a {
      font-weight: 500;
      color: #334155;
      padding: 6px 2px;
      border-bottom: 2px solid transparent;
      transition: 0.2s;
    }
    .nav-links a:hover {
      color: #0066cc;
      border-bottom-color: #0066cc;
    }
    .nav-download-btn {
      background: linear-gradient(135deg, #0066cc, #004b8c);
      color: #fff !important;
      padding: 10px 22px;
      border-radius: 30px;
      font-weight: 600;
      box-shadow: 0 6px 16px rgba(0,102,204,0.25);
      border-bottom: none !important;
    }
    .nav-download-btn:hover {
      background: #0077e6;
      color: #fff !important;
    }
    footer {
      background: #f1f5f9;
      padding: 55px 0 30px;
      margin-top: 70px;
      border-top: 1px solid #e2e8f0;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
      gap: 35px;
    }
    .footer-grid h4 {
      margin-bottom: 12px;
      color: #0f172a;
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
      gap: 24px;
    }
    details.faq-card {
      padding: 18px 22px;
      margin-bottom: 10px;
      border-radius: 16px;
    }
    details.faq-card summary {
      font-weight: 600;
      cursor: pointer;
      list-style: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    details.faq-card summary::-webkit-details-marker {
      display: none;
    }
    details.faq-card p {
      margin-top: 12px;
      color: #475569;
    }
    .intro-text {
      font-size: 1.15rem;
      max-width: 850px;
      margin: 0 auto 40px;
      text-align: center;
      color: #334155;
      line-height: 1.8;
    }
    .download-hero {
      text-align: center;
      padding: 20px 0 30px;
    }
  </style>