.book .book-body .page-wrapper .page-inner {
  max-width: 80%;
}

.html-widget.gauge {
  height: 320px; /*or try sth like 320px instead of 100%, whatever you prefer*/
}

.html-widget.gauge svg {
  height: 320px; /*or try sth like 320px instead of 100%, whatever you prefer*/
  margin-top: -10px;
  margin-bottom: -40px;
}