html, body {
    margin: 0;
    height: 100%;
}

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

.centering {
    padding: 15px;
    max-width: 800px;
}

@media screen and (min-width: 601px) {
    .centering {
        position: absolute;
        left:25%;
        transform: translate(-25%,0);
    }
}