#theme-toggle-btn {
  background: none;
  border: none;
  color: white; 
  font-size: 1.5rem; 
  cursor: pointer;
  margin-left: 20px;
  transition: color 0.3s;
}

#theme-toggle-btn:hover {
  color: #ffc800; 
}

body.dark-theme {
  background-color: #121212; 
  color: #eeeeee; 
}

body.dark-theme header,
body.dark-theme footer {
  background-color: #1a1a1a;
  box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.5);
}

body.dark-theme nav a {
  color: #ffffff;
}
body.dark-theme nav a:hover {
  color: #ffc800;
}

body.dark-theme .search-bar input {
  background-color: #333;
  color: white;
  border: 1px solid #444;
}

body.dark-theme .filters,
body.dark-theme .book-card,
body.dark-theme .book-container,
body.dark-theme .order-summary,
body.dark-theme .payment-form,
body.dark-theme .related-box {
  background-color: #1e1e1e; 
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.4);
}

body.dark-theme .results h1,
body.dark-theme .book-card h3,
body.dark-theme .book-card span,
body.dark-theme .book-info h1,
body.dark-theme .book-info .price,
body.dark-theme .filters h2,
body.dark-theme .filters h3,
body.dark-theme .filters label,
body.dark-theme .order-summary h2,
body.dark-theme .payment-form h2,
body.dark-theme .payment-form h3,
body.dark-theme .related h2,
body.dark-theme .related-box h3,
body.dark-theme main h2 {
  color: #ffffff;
}

body.dark-theme .book-card p,
body.dark-theme .book-info .author,
body.dark-theme .book-info .description,
body.dark-theme .related-box span {
  color: #bbbbbb;
}

body.dark-theme .payment-form input {
  background-color: #333;
  border: 1px solid #555;
  color: white;
}

body.dark-theme .payment-form input::placeholder {
  color: #888;
}

body.dark-theme .author-box h3,
body.dark-theme .book-box .book-text,
body.dark-theme .book-box h3,
body.dark-theme .book-box p,
body.dark-theme .book-box span {
    color: #000000 !important; 
    text-shadow: none;
}

body.dark-theme .cart-summary h2,
body.dark-theme .cart-summary span,
body.dark-theme .cart-summary p,
body.dark-theme .cart-summary div {
    color: #333333 !important;
}

body.dark-theme .cart-item h3,
body.dark-theme .cart-item p,
body.dark-theme .cart-item .price,
body.dark-theme .item-total span {
    color: #333333 !important;
}

body.dark-theme .item-total {
    color: #ffc800 !important; 
}

body.dark-theme .cart-item,
body.dark-theme .summary-row {
    border-bottom-color: #ddd; 
}