Colgroup and Col aren't visible on desktop

Question

I have simple table on which I'm trying to add colgroup and col but they aren't visible. It is also partly break the responsiveness of the table.

On mobile version the red cols are visible but are wrong.

Here is the table

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>

And here is the Jsfiddle where you can see the responsiveness: https://jsfiddle.net/d5yfteck/

How can I use colgroup and col?

Answer 1

This line:

 table tr {
      background-color: #f8f8f8;
    }

is overriding the colgroup definitions.

Without that line your code is working fine: your code with colgroup

UPDATE:

If you wish to achieve the same effect on mobile, in your mobile layout the columns presented as rows so one solution is to use classes in the media tag (.red .yellow), also see that tbody should be set with other color.