html,
body {
    margin: 0;
    height: 100%;
    overflow: hidden;
    overflow-y: hidden;
}

.center {
    height: 100%;
    position: relative;
}

.center h1 {
    text-align: center;
    font-size: 12vw;
    margin: 0;
    position: absolute;
    top: 50%;
    left: 50%;
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
}