.pinwheelmodal {
 display:none;
 position:fixed;
 z-index:1000;
 top:0;
 left:0;
 height:100%; 
 width:100%;
 background:rgba(255,255,255,.8)
  url('/animatedpinwheel.gif')
  50% 50%
  no-repeat;
}

body.loading{
 overflow:hidden;
}

body.loading .pinwheelmodal {
 display:block;
}