body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f4f4f4;
  color: #222;
}
header {
  border-bottom: 1px solid #ccc;
  padding: 16px;
}
h1 {
  margin: 0 0 8px 0;
  font-size: 20px;
  font-weight: 600;
}
nav a {
  margin-right: 14px;
  text-decoration: none;
  color: #1a1a1a;
}
nav a:hover {
  text-decoration: underline;
}
main {
  padding: 24px;
  max-width: 900px;
}
textarea, input {
  width: 100%;
  margin-top: 8px;
  padding: 8px;
  border: 1px solid #bbb;
  font-family: ui-monospace, monospace;
  font-size: 14px;
}
button {
  margin-top: 8px;
  padding: 6px 12px;
  border: 1px solid #999;
  background: #eaeaea;
  cursor: pointer;
}
button:hover {
  background: #ddd;
}
h2 {
  margin-top: 0;
  font-size: 18px;
}