html, body {
    height:100%;
    width:100%;
    height:100vh;
    width:100vw;
    margin:0;
    padding:0;
    overflow:hidden;
}
.fill-viewport {
    position:fixed;
    top:0;
    left:0;
    right:0;
    bottom:0;
    padding:0;
    margin:0;
    overflow: hidden;
}
.fill-viewport.landscape-left {
    left: env(safe-area-inset-left);
}
.fill-viewport.landscape-right {
    right: env(safe-area-inset-right);
}
#viewer {
    z-index:1;
}
#preloadContainer {
    z-index:2;
    opacity:0;
    background-color:rgba(255,255,255,1);
    transition: opacity 0.5s;
    -webkit-transition: opacity 0.5s;
    -moz-transition: opacity 0.5s;
    -o-transition: opacity 0.5s;
}