/* YOUR CUSTOM STYLES */

.centerMarker{
  position:absolute;
  /*url of the marker*/
  background:url(http://maps.gstatic.com/mapfiles/markers2/marker.png) no-repeat;
  /*center the marker*/
  top:50%;left:50%;
  z-index:1;
  /*fix offset when needed*/
  margin-left:-10px;
  margin-top:-34px;
  /*size of the image*/
  height:34px;
  width:20px;
  cursor:pointer;
}