Basic CSS loader with overlay

An element that will show loading on top of everything else (or below z-index 9999). Note that it's hidden (display: none) but it's up to you to show it at the right time ;)

#loader{
    position: fixed;
    left: 0px;
    top: 0px;
    width: 100%;
    height: 100%;
    z-index: 9999;
    background: url('/img/loading.svg') 50% 50% no-repeat rgb(255,255,255,0.5);
    display: none;
}