body {
  font: 18px Roboto, sans-serif;
  color: #333;
  background: #eee;
  margin: 30px;
}

a,
a:visited,
a:hover,
a:active {
  text-decoration: none;
  color: #862633;
}

details {
  margin: 20px 0 0 0;
}

details.hint {
  border: 2px solid #e7b37b;
  background: #fff5e9;
  padding: 8px;
  border-radius: 10px;
}

details.solution {
  border: 2px solid #a8525d;
  background: #ffe7ea;
  padding: 8px;
  border-radius: 10px;
}

details.hint summary,
details.solution summary {
  cursor: pointer;
  font-weight: bold;
}

hr {
  margin: 42px 0;
}