body {
  font-family: monospace;
  background: #111;
  color: #eee;
  padding: 20px;
}
textarea {
  width: 100%;
  background: #222;
  color: #0f0;
  border: 1px solid #555;
}
pre {
  background: #222;
  color: #0f0;
  padding: 10px;
}
button {
  background: #444;
  color: white;
  padding: 8px 16px;
  border: none;
}