#layer {
    width: 100%;
    height: 100%;
    background: #000000 url(../../../BILD-URL);
    position: absolute;
    z-index: 999999;
}

#loginform {
    width: 50%;
    margin: auto;
}

#layertext {
    box-sizing: border-box;
    margin: auto;
    margin-top: 10%;
    padding: 10px;
    width: 50%;
}