img.center {
    display: block;
    margin-left: auto;
    margin-right: auto;
}

.md-button {
    text-align: center;
}

.very-very-big {
    font-size: 40pt;
}

.very-big {
    font-size: 18pt;
}

.md-typeset table:not([class]) td, .md-typeset table:not([class]) th {
    vertical-align: middle;
    padding: .5em 1em;
}