body, html {
    font-family: "Segoe UI", "Helvetica Neue", Helvetica, Verdana, san-serif;
    height: 100%;
    width: 100%;
    padding: 0 !important;
    margin: 0 !important;
    background-color: #414141;
    color: #d4d4d4;
}

.mainDiv {
    position: absolute;
    top: calc(100% / 2 - 256px);
    left: calc(100% / 2 - 256px);
    text-align: center;
    padding-top: 36px;
    width: 512px;
    height: 180px;
    letter-spacing: 7px;
}