h2.book-subtitle1 {
  text-align: center;
  page-break-after: avoid;
  margin-bottom: 1em;
  margin-top: 2em;
}
h3.chapter-subtitle1s {
  text-align: center;
  page-break-after: avoid;
  margin-bottom: 1em;
  margin-top: 0em;
}
h3.chapter-subtitle1 {
  text-align: center;
  page-break-after: avoid;
  margin-bottom: 3em;
  margin-top: 0em;
}
h2.chapter-numbers {
  text-align: center;
  page-break-after: avoid;
  margin-top: 2em;
  margin-bottom: 2em;
}