body {
  font-family: Georgia, serif;
  font-size: 1.2em;
  line-height: 1.6;
  margin: 0;
  padding: 20px;
  background-color: #ffffff;
  color: #000000;
  transition: background-color 0.3s, color 0.3s;
}
header {
  text-align: center;
  margin-bottom: 30px;
}
button {
  display: block;
  margin: 40px auto;
  padding: 10px 20px;
  font-size: 1em;
  background-color: #444;
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}
button:hover {
  background-color: #666;
}
.toggle-theme {
  position: fixed;
  top: 10px;
  right: 10px;
}
.dark-mode {
  background-color: #121212;
  color: #ffffff;
}