.books-intro {
  text-align: center;
  max-width: 800px;
  margin: 0 auto 3rem auto;
}

.books-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
  gap: 3rem;
  max-width: 1200px;
  margin: 0 auto;
}

.book-card {
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
  overflow: hidden;
}

.book-header {
  padding: 2rem 2rem 1rem 2rem;
  text-align: center;
}

.book-image {
  max-width: 300px;
  width: 100%;
  height: auto;
  margin: 0 auto 1.5rem auto;
  display: block;
  border-radius: 8px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.book-title {
  color: #1a365d;
  margin-bottom: 0.5rem;
  font-size: 1.8rem;
  font-weight: 700;
}

.bestseller-badge {
  background: linear-gradient(45deg, #ff6b6b, #ee5a24);
  color: white;
  padding: 0.3rem 1rem;
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: 700;
  display: inline-block;
  margin-bottom: 1rem;
}

.book-content {
  padding: 0 2rem;
}

.book-description {
  line-height: 1.6;
  margin-bottom: 1.5rem;
  color: #2d3748;
}

.purchase-section {
  padding: 1.5rem 2rem 2rem 2rem;
  background: #f8f9fa;
  border-top: 1px solid #e9ecef;
}

.purchase-section h4 {
  color: #1a365d;
  margin-bottom: 1rem;
  font-size: 1.1rem;
  font-weight: 600;
}

.purchase-links {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0.8rem;
  margin-bottom: 1rem;
}

.purchase-link {
  display: inline-block;
  padding: 0.7rem 1.2rem;
  background: linear-gradient(45deg, #667eea, #764ba2);
  color: white;
  text-decoration: none;
  border-radius: 6px;
  text-align: center;
  font-weight: 500;
  transition: all 0.3s ease;
  font-size: 0.9rem;
}

.purchase-link:hover {
  background: linear-gradient(45deg, #5a67d8, #6b46c1);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  color: white;
}

.purchase-link.primary {
  background: linear-gradient(45deg, #48bb78, #38a169);
}

.purchase-link.primary:hover {
  background: linear-gradient(45deg, #38a169, #2f855a);
}

.additional-formats {
  font-size: 0.9rem;
  color: #6a737d;
  font-style: italic;
  margin-top: 0.8rem;
}

.bonus-section {
  margin-top: 2rem;
  padding: 2rem 2rem 0 2rem;
  border-top: 2px solid #e9ecef;
}

.bonus-title {
  color: #e53e3e;
  font-size: 1.3rem;
  margin-bottom: 1rem;
  font-weight: 600;
}

.bonus-content {
  background: #fff5f5;
  padding: 1.5rem;
  border-radius: 8px;
  border-left: 4px solid #e53e3e;
  margin-bottom: 1.5rem;
}

.bonus-link {
  background: linear-gradient(45deg, #e53e3e, #c53030);
  color: white;
  padding: 0.8rem 1.5rem;
  border-radius: 6px;
  text-decoration: none;
  display: inline-block;
  font-weight: 600;
  transition: all 0.3s ease;
}

.bonus-link:hover {
  background: linear-gradient(45deg, #c53030, #9c2626);
  transform: translateY(-2px);
  color: white;
}

/* Responsive Design */
@media (max-width: 768px) {
  .books-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .book-header {
    padding: 1.5rem 1.5rem 1rem 1.5rem;
  }

  .book-content {
    padding: 0 1.5rem;
  }

  .purchase-section {
    padding: 1.5rem;
  }

  .purchase-links {
    grid-template-columns: 1fr;
  }
}