body {
  font-family: Arial, sans-serif;
  text-align: center;
  background: #f9f9f9;
  margin: 0;
  padding: 0;
}
header {
  background: #d32f2f;
  color: white;
  padding: 2rem;
}
main { padding: 2rem; }
.btn {
  display: inline-block;
  padding: 0.75rem 1.25rem;
  margin-top: 1rem;
  background: #d32f2f;
  color: white;
  text-decoration: none;
  border-radius: 5px;
}
footer {
  margin-top: 2rem;
  padding: 1rem;
  background: #333;
  color: #fff;
}