body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  text-align: center;
}

header {
  background: #3b82f6;
  color: white;
  padding: 2rem 1rem;
}

main {
  padding: 2rem;
}

button {
  padding: 1rem 2rem;
  background-color: #16a34a;
  color: white;
  border: none;
  border-radius: 5px;
  font-size: 1rem;
  cursor: pointer;
}