.shelf {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-around;
  padding: 20px;
}

.shelf-item {
  position: relative;
  margin: 10px;
  transition: transform 0.3s;
}

.shelf-item:hover {
  transform: scale(1.05);
}

.modal {
  display: none;
  position: fixed;
  z-index: 1000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgba(0, 0, 0, 0.5);
}

.modal-content {
  background-color: #fefefe;
  margin: 15% auto;
  padding: 20px;
  border: 1px solid #888;
  width: 80%;
}

.close {
  color: #aaa;
  float: right;
  font-size: 28px;
  font-weight: bold;
}

.close:hover,
.close:focus {
  color: red;
  text-decoration: none;
  cursor: pointer;
}