nav {
  overflow: hidden;
}

.summary {
  position: relative;
  top: -57px;
}

.book-summary {
  background: #f3f3f3;
  overflow: auto;
}

.book-summary::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

.book-summary::-webkit-scrollbar-thumb {
  border-radius: 4px;
  background-color: #b6bcca;
  cursor: pointer;
}

.book-summary::-webkit-scrollbar-track-piece {
  background-color: #f5f5f5;
}