.preloader {
    background: rgba(0, 0, 0, 0.57);
    bottom: 0;
    left: 0;
    position: fixed;
    right: 0;
    top: 0;
    z-index: 9999;
}
.loader {
    background-image: url("../../images/mindarc/loader.gif");
    background-position: center;
    background-repeat: no-repeat;
    height: 200px;
    left: 50%;
    margin: -100px 0 0 -100px;
    position: absolute;
    top: 50%;
    width: 200px;
}