details {
display:list-item;
border: 1px solid #aaa;
border-radius: 4px;
padding: 0.5em 0.5em 0;
margin-bottom:30px;
}

summary {
font-weight: bold;
margin: -0.5em -0.5em 0;
padding: 0.5em;
}

details[open] {
padding: 0.5em;
}

details[open] summary {
border-bottom: 1px solid #aaa;
margin-bottom: 0.5em;
}