body {
  font-family: Arial, sans-serif;
  background: #f5f5f5;
  margin: 0;
}

header {
  background: #333;
  color: #fff;
  padding: 1rem;
  text-align: center;
}

#estante {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding: 20px;
  justify-content: center;
}

.livro {
  width: 40px;
  height: 200px;
  background: #444;
  color: white;
  writing-mode: vertical-rl;
  text-align: center;
  font-size: 12px;
  cursor: pointer;
  border-radius: 3px;
  transform: rotateY(10deg);
  transition: transform 0.3s;
}

.livro:hover {
  transform: rotateY(0deg) scale(1.05);
}

.modal {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  justify-content: center;
  align-items: center;
}

.modal-content {
  background: #fff;
  padding: 20px;
  width: 300px;
  border-radius: 8px;
}