.preloader {
    position: fixed;
    width: 100%;
    height: 100%;
    z-index: 999999;
    background: #111 url("/img/container_background_dark.jpg") no-repeat center -160px fixed;

    left: 0;
    top: 0;
    display: -webkit-box;
    display: -ms-flexbox;
    /*display: flex;*/
    -webkit-box-pack: center;
    -ms-flex-pack: center; 
    justify-content: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -webkit-transition: all .2s ease .2s;
    transition: all .2s ease .2s;
}
img { 
    max-width: 100%;
    height: auto;
}