For some reason, The text inside the table still is not centered. Why? How do I center the text inside the table?
To make it really Clear: For example, I want "Lorem" to sit in the middle of the four "1". 
@import url('http://twitter.github.com/bootstrap/assets/css/bootstrap.css');
table,
thead,
tr,
tbody,
th,
td {
  text-align: center;
}
<table class="table">
  <thead>
    <tr>
      <th>1</th>
      <th>1</th>
      <th>1</th>
      <th>1</th>
      <th>2</th>
      <th>2</th>
      <th>2</th>
      <th>2</th>
      <th>3</th>
      <th>3</th>
      <th>3</th>
      <th>3</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td colspan="4">Lorem</td>
      <td colspan="4">ipsum</td>
      <td colspan="4">dolor</td>
    </tr>
  </tbody>
</table>