body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  margin: 0;
  padding: 20px;
  background: #fafafa;
}

header {
  margin-bottom: 16px;
}

h1 {
  margin: 0 0 4px 0;
  font-size: 24px;
}

header p {
  margin: 0 0 8px 0;
  color: #555;
  font-size: 14px;
}

#level-filter {
  font-size: 13px;
  color: #444;
}

#level-filter label {
  cursor: pointer;
}

#layout {
  display: grid;
  grid-template-columns: 3fr 1fr;
  gap: 16px;
}

#graph {
  border: 1px solid #ddd;
  background: white;
  border-radius: 4px;
}

#detail {
  border: 1px solid #ddd;
  background: white;
  border-radius: 4px;
  padding: 16px;
  font-size: 14px;
}

#detail h2 {
  margin: 0 0 8px 0;
  font-size: 16px;
}

#detail p {
  margin: 4px 0;
}

.node {
  cursor: pointer;
}

.node:hover circle {
  stroke-width: 3;
}