Colgroup и Col не видны на рабочем столе

table {
  border: 1px solid #ccc;
  border-collapse: collapse;
  margin: 0;
  padding: 0;
  width: 100%;
  table-layout: fixed;
}

table caption {
  font-size: 1.5em;
  margin: .5em 0 .75em;
}

table tr {
  background-color: #f8f8f8;
  border: 1px solid #ddd;
  padding: .35em;
}

table th,
table td {
  padding: .625em;
  text-align: center;
}

table th {
  font-size: .85em;
  letter-spacing: .1em;
  text-transform: uppercase;
}

@media screen and (max-width: 600px) {
  table {
    border: 0;
  }

  table caption {
    font-size: 1.3em;
  }
  
  table thead {
    border: none;
    clip: rect(0 0 0 0);
    height: 1px;
    margin: -1px;
    overflow: hidden;
    padding: 0;
    position: absolute;
    width: 1px;
  }
  
  table tr {
    border-bottom: 3px solid #ddd;
    display: block;
    margin-bottom: .625em;
  }
  
  table td {
    border-bottom: 1px solid #ddd;
    display: block;
    font-size: .8em;
    text-align: right;
  }
  
  table td::before {
    content: attr(data-label);
    float: left;
    font-weight: bold;
    text-transform: uppercase;
  }
  
  table td:last-child {
    border-bottom: 0;
  }
}

<table>
  <caption>Statement Summary</caption>
  <colgroup>
    <col span = "2" style = "background-color:red; text-align: center;">
    <col style = "background-color:yellow">
  </colgroup>
  <thead>
    <tr>
      <th scope = "col">Account</th>
      <th scope = "col">Due Date</th>
      <th scope = "col">Amount</th>
      <th scope = "col">Period</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td data-label = "Account">Visa - 3412</td>
      <td data-label = "Due Date">04/01/2016</td>
      <td data-label = "Amount">$1,190</td>
      <td data-label = "Period">03/01/2016 - 03/31/2016</td>
    </tr>
    <tr>
      <td scope = "row" data-label = "Account">Visa - 6076</td>
      <td data-label = "Due Date">03/01/2016</td>
      <td data-label = "Amount">$2,443</td>
      <td data-label = "Period">02/01/2016 - 02/29/2016</td>
    </tr>
    <tr>
      <td scope = "row" data-label = "Account">Corporate AMEX</td>
      <td data-label = "Due Date">03/01/2016</td>
      <td data-label = "Amount">$1,181</td>
      <td data-label = "Period">02/01/2016 - 02/29/2016</td>
    </tr>
    <tr>
      <td scope = "row" data-label = "Account">Visa - 3412</td>
      <td data-label = "Due Date">02/01/2016</td>
      <td data-label = "Amount">$842</td>
      <td data-label = "Period">01/01/2016 - 01/31/2016</td>
    </tr>
  </tbody>
</table>