body {
      font-family: Arial, sans-serif;
      margin: 20px;
      background: #f9f9f9;
    }
    .container {
      max-width: 700px;
      margin: 0 auto;
      text-align: center;
      background: #fff;
      border-radius: 8px;
      padding: 20px;
      box-shadow: 0 0 10px rgba(0,0,0,0.1);
    }
    h1 {
      margin-top: 0;
    }
    #pdfFile {
      margin: 15px 0;
    }
    #pdfViewer {
      width: 100%;
      height: 500px;
      margin-top: 15px;
      border: 1px solid #ccc;
      border-radius: 4px;
    }
    .pages-selection {
      text-align: left;
      margin: 20px auto;
      display: inline-block;
    }
    .buttons {
      margin-top: 15px;
    }
    .buttons button {
      margin: 0 5px;
      padding: 10px 15px;
      cursor: pointer;
      background-color: #007BFF;
      border: none;
      border-radius: 4px;
      color: #fff;
      font-size: 14px;
    }
    .buttons button:hover {
      background-color: #0056b3;
    }
    .checkbox-item {
      margin-right: 10px;
    }
    .footer {
      margin-top: 20px;
      font-size: 0.9em;
      color: #444;
    }