.spacer:after {
  visibility: hidden;
  display: block;
  font-size: 0;
  content: " ";
  clear: both;
  height: 0;
}
.spacer{ display: inline-block; }

/* start commented backslash hack \*/
* html .spacer { height: 1%; }
.spacer { display: block; }
/* close commented backslash hack */