body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      margin: 0;
      background: #f5f7fa;
      color: #333;
      line-height: 1.6;
    }
    .container {
      max-width: 900px;
      margin: 40px auto;
      padding: 0 20px 60px;
      background: #fff;
      border-radius: 8px;
      box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    }
    header {
      text-align: center;
      padding: 40px 20px 20px;
    }
    header h1 {
      font-weight: 700;
      margin-bottom: 12px;
      font-size: 2.5rem;
      color: #222;
    }
    header p {
      font-size: 1.15rem;
      color: #555;
      max-width: 700px;
      margin: 0 auto;
    }
    section.features {
      margin-top: 40px;
    }
    section.features h2 {
      font-size: 1.8rem;
      margin-bottom: 20px;
      color: #222;
      border-bottom: 2px solid #4a90e2;
      display: inline-block;
      padding-bottom: 4px;
    }
    .grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
      gap: 20px;
      margin-top: 25px;
    }
    .card {
      background: #eaf1fb;
      border-radius: 8px;
      padding: 20px;
      box-shadow: inset 2px 2px 5px rgba(255,255,255,0.7);
      text-align: center;
      cursor: pointer;
      user-select: none;
      transition: transform 0.2s ease;
      display: flex;
      flex-direction: column;
      align-items: center;
    }
    .card:hover {
      transform: translateY(-5px);
      box-shadow: 0 8px 15px rgba(74,144,226,0.3);
    }
    .code-icon {
      font-family: 'Courier New', Courier, monospace;
      font-weight: 700;
      font-size: 1.5rem;
      color: #4a90e2;
      background: #dbe9fc;
      padding: 12px 20px;
      border-radius: 8px;
      user-select: none;
      margin-bottom: 15px;
      box-shadow: inset 1px 1px 3px rgba(255,255,255,0.8);
      min-width: 120px;
    }
    .card h3 {
      font-size: 1.25rem;
      margin-bottom: 10px;
      color: #2c3e50;
    }
    .card p.brief {
      font-size: 0.95rem;
      color: #3b4a61;
      margin-bottom: 10px;
      pointer-events: none;
    }
    .accordion-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      text-align: left;
      font-size: 0.9rem;
      color: #2f3d55;
      margin-top: 10px;
      padding-left: 5px;
      border-left: 3px solid #4a90e2;
      align-self: stretch;
    }
    .accordion-content.open {
      max-height: 500px;
    }
    .cta {
      text-align: center;
      margin: 50px 0 60px;
    }
    .cta a {
      background-color: #4a90e2;
      color: #fff;
      font-weight: 700;
      text-decoration: none;
      padding: 15px 40px;
      border-radius: 30px;
      font-size: 1.3rem;
      transition: background-color 0.3s ease;
      box-shadow: 0 4px 10px rgba(74,144,226,0.4);
      display: inline-block;
    }
    .cta a:hover {
      background-color: #357abd;
      box-shadow: 0 6px 15px rgba(53,122,189,0.6);
    }
    footer {
      text-align: center;
      font-size: 0.9rem;
      color: #777;
      padding: 20px 0;
      border-top: 1px solid #ddd;
      margin-top: 60px;
    }