book.css

#content {
    -webkit-column-width: 450px; /* Chrome, Safari, Opera */
    -webkit-column-gap: 20px; /* Chrome, Safari, Opera */
    height: -webkit-calc(100% - 100px); 
    padding-top: 50px;
		position: fixed; 
		line-height: 160%;
		color: #444;
    -webkit-margin-start: 16px;
    -webkit-margin-end: 16px;
    overflow: hidden;
}

#cover {
    height: -webkit-calc(100% - 100px); 
    width: 100%;
    padding-top: 50px;
		position: fixed; 
		text-align: center;
}

body { 
  margin: 0 0 0 0; 
  -webkit-text-size-adjust: none; /* Prevent font scaling in landscape */
}
h1 {
		line-height: 120%;
}

#header {
  -webkit-box-sizing: border-box;
  height: 45px;
  width: 100%;
  position: fixed;
  border-bottom: 1px solid lightgray;
  text-align: right;
  padding-right: 20px;
  line-height: 130%;
  vertical-align: middle;
  font-size: small;
  padding: 5 16 5 16;
  display: table;
}

#footer {
  -webkit-box-sizing: border-box;
  height: 45px;
  width: 100%;
  position: fixed;
  top: -webkit-calc(100% - 45px); 
  border-top: 1px solid lightgray;
  padding: 5 16 5 16;
  display: table;
}

.btn-left, .btn-right {
  width: 3em;
  vertical-align: middle;
  text-align: center;
  border: 1px solid black;
  border-radius: 12.5px;
  display: table-cell;
  font-size: initial;
}
.btn-left:active, .btn-right:active {
  background-color: lightgray;
}

#pg-count {
  text-align: center;
  vertical-align: middle;
  display: table-cell;
}