body {
  font-family: Arial, sans-serif;
  background: #f4f4f4;
  margin: 0;
  padding: 20px;
}
h2 { color: #2c3e50; }
button {
  background: #27ae60;
  color: #fff;
  padding: 10px;
  border: none;
  cursor: pointer;
}
button:hover {
  background: #2ecc71;
}