body {
      font-family: Arial, sans-serif;
      margin: 0;
      padding: 0;
      background-color: #f4f4f4;
      text-align: center;
      background-color: black;
      color: white;
    }

    #reader {
      margin: 20px auto;
      width: 300px;
    }

    .alert {
      display: none;
      margin: 10px auto;
      padding: 10px;
      width: 80%;
      border-radius: 5px;
      font-weight: bold;
    }

    .alert-success {
      background-color: #d4edda;
      color: #155724;
      border: 1px solid #c3e6cb;
    }

    .alert-error {
      background-color: #f8d7da;
      color: #721c24;
      border: 1px solid #f5c6cb;
    }

    table {
      width: 80%;
      margin: 20px auto;
      border-collapse: collapse;
    }

    th, td {
      padding: 10px;
      border: 1px solid #ddd;
      text-align: center;
    }

    th {
      background-color: #28a745;
      color: white;
    }