body {
  font-family: Arial, sans-serif;
  margin: 20px;
}

nav button {
  margin-right: 10px;
  padding: 8px 12px;
  cursor: pointer;
}

nav button:hover {
  background-color: #ddd;
}

nav button.active {
  font-weight: bold;
  background-color: #bbb;
}