body {
  font-family: ui-monospace, monospace;
  margin: 2rem;
  background: #111;
  color: #ddd;
}
h1 {
  font-family: system-ui, sans-serif;
  font-size: 1.1rem;
  color: #9f9;
}
pre {
  border: 1px solid #333;
  padding: 0.75rem;
  min-height: 1rem;
  white-space: pre-wrap;
}
#err {
  color: #f88;
}
small {
  color: #888;
}
#app {
  width: 100%;
  height: 8rem;
  border: 1px solid #333;
  background: #fff;
}