body {
  font-family: system-ui, sans-serif;
  margin: 0;
  padding: 2rem;
  background: #f6f8fa;
}

header, footer {
  background: #333;
  color: #fff;
  padding: 1rem;
  text-align: center;
  border-radius: 8px;
}

main {
  margin: 2rem auto;
  max-width: 700px;
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

button {
  padding: 0.6rem 1.2rem;
  margin-top: 1rem;
  border: none;
  background: #3366cc;
  color: #fff;
  font-size: 1rem;
  border-radius: 5px;
  cursor: pointer;
}

button:hover {
  background: #254a91;
}

pre {
  margin-top: 1rem;
  padding: 1rem;
  background: #eee;
  border-radius: 6px;
}