#preloading {
    width:500px;
    margin:20px auto;
    border-radius:10px;
    border:4px solid transparent;
    position:relative;
    padding:1px;
}
#preloading:before {
    content:'';
    border:1px solid #c41d1d;
    border-radius:10px;
    position:absolute;
    top:-4px;
    right:-4px;
    bottom:-4px;
    left:-4px;
}
#preloading .loaderBar {
    position:absolute;
    border-radius:10px;
    top:0;
    right:100%;
    bottom:0;
    left:0;
    background: #c41d1d;
    width:0;
    animation:borealisBar 2s linear infinite;
}

@keyframes borealisBar {
    0% {
        left:0%;
        right:100%;
        width:0%;
    }
    10% {
        left:0%;
        right:75%;
        width:25%;
    }
    90% {
        right:0%;
        left:75%;
        width:25%;
    }
    100% {
        left:100%;
        right:0%;
        width:0%;
    }
}