div.ajax_loading
{
  position: fixed;
  left: 0px;
  top: 0px;
  height: 100%;
  width: 100%;
  z-index: 99999999999999;
  background: rgba(0, 0, 0, 0.60)
}

div.ajax_loading i
{
  position: absolute;
  left: 50%;
  top: 50%;
  font-size: 80px;
  margin-left: -40px;
  margin-top: -40px;
  color: #fff;
}