body {
    position: relative;
    padding-top: 40px;
    padding-bottom: 80px;
    min-height: 100vh;
}

footer {
    position: absolute;
    bottom: 1em;
    left: 3em;
    right: 3em;
}

.margin-top {
    margin-top: 1em;
}

.spacer {
    clear: both;
    height: 1em;
}