details {
  border: 1px solid #dddddd;
  border-radius: 4px;
  padding: 0.5em 0.5em 0;
}

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

details[open] {
  padding: 0.5em;
  background-color: #f0f2ff;
}

details[open] summary {
  border-bottom: 1px solid #dddddd;
  margin-bottom: 0.5em;
  background-color: #ffffff;
}