SOURCE

<div class="book">
  <span class="page turn"></span>
  <span class="page turn"></span>
  <span class="page turn"></span>
  <span class="page turn"></span>
  <span class="page turn"></span>
  <span class="page turn"></span>
  <span class="cover"></span>
  <span class="page"></span>
  <span class="cover turn"></span>
</div>

body {
  background-color: #4F4E68;
}
.book {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  margin: auto;
  width: 18.5rem;
  height: 12.5rem;
  perspective: 70rem;
}
.cover {
  background-color: #36354e;
  transform: rotateY(0deg);
  width: 9.25rem;
  height: 12.5rem;
}
.page {
  top: 0.25rem;
  left: 0.25rem;
  background-color: #e9e6c4;
  transform: rotateY(0deg);
  width: 9rem;
  height: 12rem;
  text-align: right;
  font-size: 8px;
  color: #777;
  font-family: monospace;
}
.page::before, .page::after {
  display: block;
  border-top: 1px dashed rgba(0, 0, 0, 0.3);
  content: "";
  padding-bottom: 1rem;
}
.cover, .page {
  position: absolute;
  padding: 1rem;
  transform-origin: 100% 0;
  border-radius: 5px 0 0 5px;
  box-shadow: inset 3px 0px 20px rgba(0, 0, 0, 0.2),
    0px 0px 15px rgba(0, 0, 0, 0.1);
  box-sizing: border-box;
}
.cover.turn {
  animation: bookCover 3s forwards;
}
.page.turn {
  animation: bookOpen 3s forwards;
}
.page:nth-of-type(1) {
  animation-delay: 0.05s;
}
.page:nth-of-type(2) {
  animation-delay: 0.33s
}
.page:nth-of-type(3) {
  animation-delay: 0.66s;
}
.page:nth-of-type(4) {
  animation: bookOpen150deg 3s forwards;
  animation-delay: 0.99s;
}
.page:nth-of-type(5) {
  animation: bookOpen30deg 3s forwards;
  animation-delay: 1.2s;
}
.page:nth-of-type(6) {
  animation: bookOpen55deg 3s forwards;
  animation-delay: 1.25s;
}
@keyframes bookOpen {
  30% { z-index: 999 }
  100% {  transform: rotateY(180deg);
    z-index: 999;}
}
@keyframes bookCover {
  30% { z-index: 999 }
  100% {  transform: rotateY(180deg);
    z-index: 1;}
}
@keyframes bookOpen150deg {
  30% { z-index: 999 }
  100% {  transform: rotateY(150deg);
    z-index: 999;}
}
@keyframes bookOpen55deg {
  30% { z-index: 999 }
  100% {  transform: rotateY(55deg);
    z-index: 999;}
}
@keyframes bookOpen30deg {
  50% { z-index: 999 }
  100% {  transform: rotateY(30deg);
    z-index: 999;}
}