body {
    font-family: helvetica, arial, sans-serif;
    font-size: 9pt;
}

pre {
    font-family: monaco, monospace;
}

.overlay {
    position: absolute;
    background: rgba(0, 0, 0, 0.5);
    color: white;
    padding: 0.5em;
    white-space: normal;
    font-family: helvetica, arial, sans-serif;
}

.highlight {
    background-color: yellow;
}

.tokenization {
    cursor: pointer;
}

.parse-tree span {
    display: block;
    float: left;
}

.expression {
    margin: 0.25em;
    padding: 0.25em;
    border: 1px solid gray;
}