body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: #f8f8f8;
    color: #333;
  }
  
  header {
    background-color: #4CAF50;
    color: white;
    padding: 1.5rem;
    text-align: center;
  }
  
  main {
    padding: 2rem;
  }
  
  .books {
    margin-bottom: 2rem;
  }
  
  .book-list {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
  }
  
  .book-card {
    background: rgb(227, 226, 233);
    padding: 1rem;
    border: 1px solid #ddd;
    border-radius: 5px;
    flex: 1;
    min-width: 200px;
  }
  
  .contact button {
    margin-bottom: 1rem;
    padding: 0.5rem 1rem;
    background-color: #4CAF50;
    color: white;
    border: none;
    cursor: pointer;
  }
  
  footer {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 1rem;
    margin-top: 2rem;
  }
  /* Default Light Theme */
body {
    background-color: #f0f0f0;
    color: #333;
    transition: background-color 0.3s ease, color 0.3s ease;
  }
  
  /* Dark Mode Styles */
  body.dark-mode {
    background-color: #121212;
    color: #f5f5f5;
  }
  
  header, footer {
    transition: background-color 0.3s ease;
  }
  
  body.dark-mode header {
    background-color: #1e1e1e;
  }
  
  body.dark-mode footer {
    background-color: #1e1e1e;
  }
  
  /* Toggle Button */
  #toggle-theme {
    margin-top: 1rem;
    padding: 0.5rem 1rem;
    cursor: pointer;
    border: none;
    border-radius: 5px;
    background-color: #4CAF50;
    color: white;
  }
  
  #toggle-theme:hover {
    background-color: #388e3c;
  }