body {
      margin: 0;
      padding: 0;
      /* font-family: "Lato", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
      background-color: #e0f0ff; */
      font-size: 1rem;
      font-weight: 400;
      line-height: 1.5;
      /* color: #434747; */
      text-align: left;
      /* background-color: #ffffff;     */
    }
    .book {
      position: relative;
      width: 100%;
      max-width: 768px;
      height: 90vh;
      margin: 5vh auto;
      /* box-shadow: 0 0 20px rgba(0,0,0,0.2); */
      /* background: #fff; */
      overflow: hidden;
    }
    /* .spine {
      position: absolute;
      left: 0;
      top: 0;
      bottom: 0;
      width: 10px;
      background-color: #FF0000;
    } */
    .book::before, .book::after {
      position: absolute;
      top: 0;
      z-index: 10;
      width: 10px;
      height: 100%;
      background: -webkit-linear-gradient(left, #dddddd 33.33%, #f0f0f0 33.33%, #f0f0f0 66.66%, white 66.66%);
      background: linear-gradient(to right, #dddddd 33.33%, #f0f0f0 33.33%, #f0f0f0 66.66%, white 66.66%);
      background-size: 3px 100%;
      content: '';
      -webkit-backface-visibility: hidden;
      -moz-backface-visibility: hidden;
      -ms-backface-visibility: hidden;
      backface-visibility: hidden;
    }
    nav.fixed-nav {
      /* background-color: #d0e6f9; */
      padding: 0.5rem;
      text-align: center;
      position: absolute;
      width: 100%;
      z-index: 100;
    }
    nav.fixed-nav button {
      background: none;
      border: none;
      font-size: 1rem;
      margin: 0 0.5rem;
      cursor: pointer;
      /* color: #4a90e2; */
      text-decoration: none;
      font-weight: bold;
    }
    .page {
      opacity: 0;
      transform: translateX(100%);
      transition: transform 0.6s ease, opacity 0.6s ease, box-shadow 0.6s ease;
      display: none;
      position: absolute;
      width: 100%;
      height: 100%;
      /* background: white; */
      box-shadow: 0 0 0 rgba(0, 0, 0, 0);
      padding-top: 3rem;
    }
    .page.visible {
      display: block;
      opacity: 1;
      transform: translateX(0);
      z-index: 10;
      /* box-shadow: 0 0 30px rgba(0,0,0,0.2); */
    }
    .page.exit-left {
      transform: translateX(-100%);
      opacity: 0;
    }
    .page.exit-right {
      transform: translateX(100%);
      opacity: 0;
    }
    .page.slide-left {
      animation: pageFlipLeft 0.6s forwards;
    }
    .page.slide-right {
      animation: pageFlipRight 0.6s forwards;
    }
    @keyframes pageFlipLeft {
      from { transform: translateX(100%); opacity: 0; box-shadow: 0 0 0 rgba(0,0,0,0); }
      to   { transform: translateX(0); opacity: 1; box-shadow: 0 0 30px rgba(0,0,0,0.2); }
    }
    @keyframes pageFlipRight {
      from { transform: translateX(-100%); opacity: 0; box-shadow: 0 0 0 rgba(0,0,0,0); }
      to   { transform: translateX(0); opacity: 1; box-shadow: 0 0 30px rgba(0,0,0,0.2); }
    }
    .content {
      padding: 2rem;
      height: calc(100% - 9rem);
      overflow-y: auto;
    }
    .cover-image, .author-image {
      max-width: 100%;
      height: auto;
      display: block;
      margin: 0 auto 1rem;
    }
    .author-image {
        float: right;
        margin-left: 0.75rem;
        margin-top: 1rem;
        margin-bottom: -0.25rem;
    }
    .btn, button {
      background-color: transparent;
      border: none;
      cursor: pointer;
      border-radius: 5px;
      font-size: 1rem;
    }
    .button-row {
        display: flex;
        justify-content: space-between;
        position: absolute;
        bottom: 3rem;
        width: 98%;
        left: 1%;
    }
    .hide-back button:first-child {
      visibility: hidden;
    }
    .text-center {
      text-align: center !important;
    }
    form input, form textarea {
      width: 100%;
    }
    .column {
      float: left;
      width: 40%;
    }
    .row:after {
      content: "";
      display: table;
      clear: both;
    }
    .clearfix::after {
      content: "";
      display: table;
      clear: both;
    }