table,
    th,
    td {
      table-layout: fixed;
      border: 2px solid black;
      height: 50px;
      width: 50px;
    }

    body {
      background-color: #e9ecef;
      font-size: 18px;
      color: #1d2d44;
      font-family: Arial, sans-serif;
      text-align: center;
      padding-bottom: 15px;
    }

    .center {
      border: 15px solid;
      margin: auto;
      max-width: 350px;
      width: 100%;
      padding: 10px;
    }