div.ajax-loading {
  position:fixed;
  top:0;
  left:0;
  bottom:0;
  right:0;
  z-index:9999;
  background-color:rgba(0,0,0,.8);
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
}

.ajax-loading * {
  color:white;
}