body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  text-align: center;
  background: #f9f9f9;
}

header {
  background: #4CAF50;
  color: white;
  padding: 20px;
}

main {
  padding: 20px;
}

button {
  padding: 10px 20px;
  margin-top: 10px;
  border: none;
  background: #4CAF50;
  color: white;
  cursor: pointer;
  border-radius: 5px;
}

button:hover {
  background: #45a049;
}

footer {
  margin-top: 30px;
  background: #333;
  color: white;
  padding: 10px;
}