.easy { color: #00cc00; }
.moderate { color: #0066ff; }
.hard { color: #ff3300; }

div.lab-required, div.lab-challenge, div.lab-question, div.lab-warning, div.lab-prereq {
    margin-left: auto;
    margin-right: auto;
    margin-bottom: 1em;
    margin-top: 1em;
    width: 80%;
    background-color: #e0e0ff;
    padding-left: 1em;
    padding-right: 1em;
    box-sizing: content-box;
}

div[class^="lab-"] p {
    margin-block-start: 1em;
    margin-block-end: 1em;
}

div.lab-required .header {
    font-weight: bold;
}

div.lab-challenge .header {
    font-style: italic;
}

div.lab-question .header {
    font-weight: bold;
}

div.lab-required {
    background-color: #e0e0ff;
    border: 1px solid #c0c0ff;
}

div.lab-challenge {
    background-color: #ffe0e0;
    border: 1px solid #ffc0c0;
}

div.lab-question {
    background-color: #e0e0ff;
    border: 1px solid #c0c0ff;
}

div.lab-warning {
    background-color: #ffe0e0;
    border: 1px solid #ffc0c0;
}

div.lab-prereq {
    background-color: #FFEFD5;
    border: 1px solid #ffc0c0;
}

kbd {
    background-color: #ffffff;
    color: #007700;
    font-family: monospace;
    font-weight: bold;
}