.chapters {
  background-color: #fff;
  padding: 2em; }
  .chapters ul {
    margin-left: -1.5em;
    font-size: 0.85em; }
  .chapters li {
    margin: 0.75em 0;
    position: relative;
    padding-left: 2em; }
    .chapters li.expanded > ul {
      max-height: 99999px;
      opacity: 1; }
    .chapters li.expanded > button span {
      transform: rotateZ(45deg); }
    .chapters li button {
      border: 1px solid #3f3f3f;
      color: #3f3f3f;
      background-color: transparent;
      padding: 0px;
      text-align: center;
      box-sizing: border-box;
      margin-right: 0.5em;
      border-radius: 2px;
      position: absolute;
      top: 3px;
      left: 0%; }
      .chapters li button:hover {
        background-color: transparent; }
      .chapters li button:focus {
        outline: none; }
      .chapters li button span {
        margin: 0;
        padding: 0;
        text-align: center;
        display: block;
        box-sizing: border-box;
        line-height: 25px;
        height: 25px;
        width: 25px;
        font-size: 25px;
        font-weight: 100;
        transition: all 0.15s; }
        .chapters li button span:before {
          box-sizing: border-box; }
    .chapters li a {
      text-decoration: none; }
      .chapters li a:hover {
        color: #8b8b8b; }
    .chapters li ul {
      max-height: 0px;
      overflow: hidden;
      opacity: 0;
      transition: opacity 0.15s; }

.chapter-nav {
  text-align: center;
  margin-bottom: 0.5em; }
  .chapter-nav a {
    display: inline-block;
    margin: 0 10px; }