body {
  font-family: system-ui, sans-serif;
  background-color: #ffffff;
  color: #111111;
  padding: 2rem;
  transition: background-color 0.3s, color 0.3s;
}

body.dark-mode {
  background-color: #111111;
  color: #f1f1f1;
}

.theme-toggle {
  position: fixed;
  top: 1rem;
  right: 1rem;
}

button {
  padding: 0.5rem 1rem;
  background-color: #2c3e50;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}

button:hover {
  background-color: #1a252f;
}

h1, h2 {
  margin-top: 1.5rem;
}