/*HTML 5 specific*/
header, section, aside, footer{
  display: block;
}

.group-header {
  clear: both;
}

.group-left {
  width: 25%;
  float: left;
}

.group-middle {
  width: 50%;
  float: left;
}

.group-right {
  width: 25%;
  float: right;
}

.group-footer {
  clear: both;
}