* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
  color: #1a1a1a;
  background: #fafafa;
}

header {
  padding: 3rem 1.5rem;
  text-align: center;
  background: #111;
  color: #fff;
}

header h1 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

main {
  max-width: 640px;
  margin: 2rem auto;
  padding: 0 1.5rem;
}

section {
  margin-bottom: 2rem;
}

section h2 {
  margin-bottom: 0.5rem;
}

button {
  background: #111;
  color: #fff;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: 6px;
  font-size: 1rem;
  cursor: pointer;
}

button:hover {
  background: #333;
}

#output {
  margin-top: 1rem;
  font-weight: 500;
}

footer {
  text-align: center;
  padding: 2rem 1.5rem;
  color: #666;
  font-size: 0.9rem;
}