body {
  font-family: Arial, sans-serif;
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
}

.btn {
  display: inline-block;
  padding: 6px 16px;
  border: 1px solid #555;
  border-radius: 4px;
  color: #333;
  text-decoration: none;
  font-size: 0.9em;
  transition:
    background-color 0.15s,
    color 0.15s;
}

.btn:hover {
  background-color: #333;
  color: #fff;
}