This relevant CSS code applies to this page:

  #red-bordered-main-content-floated-left
  {
  border: solid red;
  float: left;
  margin: 16px;
  padding: 8px;
  width: 70%;
  }

  #green-bordered-footer
  {
  border: solid green;
  padding: 8px;
  }

  hr#cleared-both {border: 16px solid; clear: both;}