.fullscreen {
    background-color: #ffffff;
    width: 100%;
    height: auto;
    bottom: 0px;
    top: 0px;
    left: 0;
    position: absolute;
}
.center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 54pt;
    font-weight: bolder;
    font-family: Arial, Helvetica, sans-serif;
}