body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}
header, main, footer {
  width: 100%;
  max-width: 800px;
  padding: 1rem;
}
.logo {
  max-width: 112px;
  margin: auto;
}
.book {
  background: white;
  margin: 1rem auto;
  padding: 1rem;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}
.carousel {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}
.carousel-images {
  width: 100%;
  max-height: 300px;
  overflow: hidden;
}
.carousel-image {
  width: 100%;
  max-height: 300px;
  object-fit: contain;
}
.prev, .next {
  background: none;
  border: none;
  font-size: 2rem;
  cursor: pointer;
}
#summary {
  margin-top: 2rem;
  background: #e8f5e9;
  padding: 1rem;
  border-radius: 6px;
}
#paypal-button {
  margin-top: 1rem;
  padding: 0.5rem 1rem;
  font-size: 1rem;
}
footer {
  margin-top: 2rem;
  font-size: 0.9rem;
  color: #555;
}