.book .book-summary .chapter > .articles {
  overflow: hidden;
  max-height: 0px;
}

.book .book-summary .chapter.expanded > .articles {
  max-height: 9999px;
}

.book .book-summary .exc-trigger {
  position: absolute;
    left: 12px;
    top: 12px;
}

.book .book-summary ul.summary li a,
.book .book-summary ul.summary li span {
  padding-left: 30px;
  cursor: pointer;
  transition: all .2s;
}

.book .book-summary ul.summary li a:hover,
.book .book-summary ul.summary li span:hover {
  color: #008ccc;
}

.book .book-summary .exc-trigger:before {
    content: "\f105";
}

.book .book-summary .expanded > a .exc-trigger:before,
.book .book-summary .expanded > span .exc-trigger:before {
  content: "\f107";
}