<style type="text/css">
  /*this must be set so that the loading div
    can be height:100% */
	body{height:100%}

	/*this is what we want the div to look like
    when it is not showing*/
	div.loading-invisible{
	  /*make invisible*/
	  display:none;
	}

	div.loading-visible {
		position: fixed;
		z-index: 999;
	    height: 4em;
	    width: 6em;
		margin: auto;
		top: 0;
		left: 0;
		bottom: 0;
		right: 0;
	}
  
	/* Transparent Overlay */
	.loading-visible:before {
	  content: '';
	  z-index: -1;
	  display: block;
	  position: fixed;
	  top: 0;
	  left: 0;
	  width: 100%;
	  height: 100%;
      background: rgba(255, 255, 255);
	}  
</style>
