body {
    font-family: Arial, sans-serif;
    text-align: center;
    background-color: #f2f2f2;
    color: #222;
    transition: background-color 0.5s, color 0.5s;
    padding: 50px;
}

.dark-mode {
    background-color: #1a1a1a;
    color: white;
}

#toggleBtn {
    background: #222;
    color: white;
    border: none;
    padding: 10px 20px;
    cursor: pointer;
    border-radius: 5px;
    margin-bottom: 30px;
    transition: 0.3s;
}

.content-card {
  max-width: 400px;
  margin: auto;
  background: white;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
  transition: background 0.5s, color 0.5s;
}

.dark-mode .content-card {
  background: #333;
  color: white;
}