[data-footnote]{
    display: inline-block;
}
[data-footnote].open{
    display: block;
}

[data-footnote-body] {
    background-color: rgba(0,0,0,0.15);
    padding: 1em;
    border-radius: 0.5em;
    margin: 1em;
    display: none;
}

[data-footnote-body].open {
    display: block;
}