body {
  font-family: sans-serif;
  background: #f4f4f4;
  color: #333;
  margin: 0;
  padding: 2rem;
}

.container {
  max-width: 800px;
  margin: 0 auto;
}

header {
  text-align: center;
  margin-bottom: 2rem;
}

.subtitle {
  color: #666;
}

.foldable .fold-content {
  display: block;
  margin-top: 1rem;
}

.foldable.collapsed .fold-content {
  display: none;
}