#loader_bg {
    position:fixed; 
    width:100%; 
    height:100%; 
    z-index:100000000000; 
    opacity:0.5; 
    background-color:#000000; 
    left:0; 
    top:0; 
    display:none;
}

#loader {
    position:absolute; 
    left:45%; 
    top:20%; 
    z-index:100000000001; 
    display:none;
    background: url('../images/gears.gif') no-repeat;
    width: 200px;
    height:200px;
}