body {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
}
.book {
  width: 50vw;
  height: 100vh;
  perspective: 500px;
  position: relative;
  float: right;
}
.book .paper {
  position: absolute;
  left: 0px;
  top: 0px;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transform-origin: left center;
  transition: all 2s ease-in;
}
.book .paper {
  z-index: 2;
}
.book .paper.current + .paper {
  z-index: 20;
}
.book .paper.current {
  z-index: 40;
}
.book .page {
  position: absolute;
  left: 0px;
  right: 0px;
  bottom: 0px;
  top: 0px;
  backface-visibility: hidden;
}
.book .page > img {
  width: 100%;
  height: 100%;
}
.book .page.front {
  background: #00b196;
}
.book .page.back {
  background: #9a9b9a;
  transform: rotateY(180deg);
}
.book .paper.flip {
  transform: rotateY(-180deg);
}
.book1 {
  width: 100vw;
  height: 50vh;
  background: #fff;
  perspective: 500px;
  position: relative;
  float: right;
}
.book1 .paper {
  position: absolute;
  left: 0px;
  top: 0px;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transform-origin: bottom;
  transition: all 2s ease-in;
}
.book1 .paper {
  z-index: 2;
}
.book1 .paper.current + .paper {
  z-index: 20;
}
.book1 .paper.current {
  z-index: 40;
}
.book1 .page {
  position: absolute;
  left: 0px;
  right: 0px;
  bottom: 0px;
  top: 2px;
  backface-visibility: hidden;
}
.book1 .page > img {
  width: 100%;
  height: 100%;
}
.book1 .page.front {
  background: #00b196;
}
.book1 .page.back {
  background: #9a9b9a;
  transform: rotateX(180deg);
}
.book1 .paper.flip1 {
  transform: rotateX(-180deg);
}
.book2 {
  width: 50vw;
  height: 100vh;
  perspective: 500px;
  position: relative;
}
.book2 .paper {
  position: absolute;
  left: 0px;
  top: 0px;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transform-origin: right center;
  transition: all 2s ease-in;
}
.book2 .paper {
  z-index: 2;
}
.book2 .paper.current + .paper {
  z-index: 20;
}
.book2 .paper.current {
  z-index: 40;
}
.book2 .page {
  position: absolute;
  left: 0px;
  right: 0px;
  bottom: 0px;
  top: 0px;
  backface-visibility: hidden;
}
.book2 .page > img {
  width: 100%;
  height: 100%;
}
.book2 .page.front {
  background: #00b196;
}
.book2 .page.back {
  background: #9a9b9a;
  transform: rotateY(180deg);
}
.book2 .paper.flip2 {
  transform: rotateY(180deg);
}
.book3 {
  width: 100vw;
  height: 50vh;
  background: #fff;
  perspective: 500px;
  position: relative;
}
.book3 .paper {
  position: absolute;
  left: 0px;
  top: 0px;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transform-origin: bottom;
  transition: all 2s ease-in;
}
.book3 .paper {
  z-index: 2;
}
.book3 .paper.current + .paper {
  z-index: 20;
}
.book3 .paper.current {
  z-index: 40;
}
.book3 .page {
  position: absolute;
  left: 0px;
  right: 0px;
  bottom: 0px;
  top: 0px;
  backface-visibility: hidden;
}
.book3 .page > img {
  width: 100%;
  height: 100%;
}
.book3 .page.front {
  background: #00b196;
}
.book3 .page.back {
  background: #9a9b9a;
  transform: rotateX(180deg);
}
.book3 .paper.flip3 {
  transform: rotateX(-180deg);
}
.base {
  width: 100%;
  height: 100vh;
  position: fixed;
}
.base1 {
  width: 100%;
  height: 100vh;
  position: fixed;
}
.base2 {
  width: 100%;
  height: 100vh;
  position: fixed;
}
.base3 {
  width: 100%;
  height: 100vh;
  position: fixed;
}
.base {
  z-index: 100;
}
.base1 {
  z-index: 99;
}
.base2 {
  z-index: 98;
}
.base3 {
  z-index: 97;
}
.book-hide {
  display: none;
}
.base-hide {
  display: none;
}