body {
    margin:0;
    padding:0;
}

.loading:before {
    content:'';
    position: fixed;
    top:0;
    left:0;
    right:0;
    bottom:0;
    background:#262626;
    z-index: 1;
}

.loading:after {
    content:'';
    position: absolute;
    display:block;
    top:50%;
    left:33.3%;
    width:33.3%;
    height:2px;
    background:rgb(84, 241, 241);
    z-index: 2;
    transform-origin: left;
    transform:scaleX(0);
    animation:animate 2s infinite alternate;
}

@keyframes animate {
    0% {
        transform:translateX(0) scaleX(0);
        transform-origin:left;
        left:33.3%;
        right:auto;
    }
     45% {
        transform:translateX(0) scaleX(1);
        transform-origin:left;
        left:33.3%;
        right:auto;
     }
     50% {
        transform:translateX(0) scaleX(1);
        transform-origin:right;
        left:auto;
        right:33.3%;
     }
     100% {
        transform:translateX(0) scaleX(0);
        transform-origin:right;
        left:auto;
        right:33.3%;
     }
}