html - Fix pure CSS book animation

I´m having a hard time trying to fix this pure CSS book animation. Currently I have the problem that the leaves are kept at the sides even when the book is closed (vertical), but I can´t find a way to fix it.

The source where I took this from is

What I did to the original, was to remove the base transform as it was causing some undesired behavior when pausing the animation at the beginning (it is sometimes needed).

.book {
  --color: #fff;
  --duration: 6.8s;
  width: 32px;
  height: 12px;
  position: relative;
  margin: 32px 0 0 0;
  zoom: 1.5;
}
.book .inner {
  width: 32px;
  height: 12px;
  position: relative;
}
.book .inner .left,
.book .inner .right {
  width: 60px;
  height: 4px;
  top: 0;
  border-radius: 2px;
  background: var(--color);
  position: absolute;
}
.book .inner .left:before,
.book .inner .right:before {
  content: "";
  width: 48px;
  height: 4px;
  border-radius: 2px;
  background: inherit;
  position: absolute;
  top: -10px;
  left: 6px;
}
.book .inner .left {
  right: 28px;
  transform-origin: 58px 2px;
  transform: rotateZ(90deg);
  -webkit-animation: left var(--duration) ease infinite;
          animation: left var(--duration) ease infinite;
}
.book .inner .right {
  left: 28px;
  transform-origin: 2px 2px;
  transform: rotateZ(-90deg);
  -webkit-animation: right var(--duration) ease infinite;
          animation: right var(--duration) ease infinite;
}
.book .inner .middle {
  width: 32px;
  height: 12px;
  border: 4px solid var(--color);
  border-top: 0;
  border-radius: 0 0 9px 9px;
  transform: translateY(2px);
}
.book ul {
  margin: 0;
  padding: 0;
  list-style: none;
  position: absolute;
  left: 50%;
  top: 0;
}
.book ul li {
  height: 4px;
  border-radius: 2px;
  transform-origin: 100% 2px;
  width: 48px;
  right: 0;
  top: -10px;
  position: absolute;
  background: var(--color);
  transform: rotateZ(0deg) translateX(-18px);
  -webkit-animation-duration: var(--duration);
          animation-duration: var(--duration);
  -webkit-animation-timing-function: ease;
          animation-timing-function: ease;
  -webkit-animation-iteration-count: infinite;
          animation-iteration-count: infinite;
}
.book ul li:nth-child(0) {
  -webkit-animation-name: page-0;
          animation-name: page-0;
}
.book ul li:nth-child(1) {
  -webkit-animation-name: page-1;
          animation-name: page-1;
}
.book ul li:nth-child(2) {
  -webkit-animation-name: page-2;
          animation-name: page-2;
}
.book ul li:nth-child(3) {
  -webkit-animation-name: page-3;
          animation-name: page-3;
}
.book ul li:nth-child(4) {
  -webkit-animation-name: page-4;
          animation-name: page-4;
}
.book ul li:nth-child(5) {
  -webkit-animation-name: page-5;
          animation-name: page-5;
}
.book ul li:nth-child(6) {
  -webkit-animation-name: page-6;
          animation-name: page-6;
}
.book ul li:nth-child(7) {
  -webkit-animation-name: page-7;
          animation-name: page-7;
}
.book ul li:nth-child(8) {
  -webkit-animation-name: page-8;
          animation-name: page-8;
}
.book ul li:nth-child(9) {
  -webkit-animation-name: page-9;
          animation-name: page-9;
}
.book ul li:nth-child(10) {
  -webkit-animation-name: page-10;
          animation-name: page-10;
}
.book ul li:nth-child(11) {
  -webkit-animation-name: page-11;
          animation-name: page-11;
}
.book ul li:nth-child(12) {
  -webkit-animation-name: page-12;
          animation-name: page-12;
}
.book ul li:nth-child(13) {
  -webkit-animation-name: page-13;
          animation-name: page-13;
}
.book ul li:nth-child(14) {
  -webkit-animation-name: page-14;
          animation-name: page-14;
}
.book ul li:nth-child(15) {
  -webkit-animation-name: page-15;
          animation-name: page-15;
}
.book ul li:nth-child(16) {
  -webkit-animation-name: page-16;
          animation-name: page-16;
}
.book ul li:nth-child(17) {
  -webkit-animation-name: page-17;
          animation-name: page-17;
}
.book ul li:nth-child(18) {
  -webkit-animation-name: page-18;
          animation-name: page-18;
}

@-webkit-keyframes page-0 {
  4% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  13%, 54% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  63% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}

@keyframes page-0 {
  4% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  13%, 54% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  63% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-1 {
  5.86% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  14.74%, 55.86% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  64.74% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-1 {
  5.86% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  14.74%, 55.86% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  64.74% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-2 {
  7.72% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  16.48%, 57.72% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  66.48% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-2 {
  7.72% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  16.48%, 57.72% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  66.48% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-3 {
  9.58% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  18.22%, 59.58% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  68.22% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-3 {
  9.58% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  18.22%, 59.58% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  68.22% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-4 {
  11.44% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  19.96%, 61.44% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  69.96% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-4 {
  11.44% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  19.96%, 61.44% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  69.96% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-5 {
  13.3% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  21.7%, 63.3% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  71.7% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-5 {
  13.3% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  21.7%, 63.3% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  71.7% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-6 {
  15.16% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  23.44%, 65.16% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  73.44% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-6 {
  15.16% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  23.44%, 65.16% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  73.44% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-7 {
  17.02% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  25.18%, 67.02% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  75.18% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-7 {
  17.02% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  25.18%, 67.02% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  75.18% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-8 {
  18.88% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  26.92%, 68.88% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  76.92% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-8 {
  18.88% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  26.92%, 68.88% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  76.92% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-9 {
  20.74% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  28.66%, 70.74% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  78.66% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-9 {
  20.74% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  28.66%, 70.74% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  78.66% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-10 {
  22.6% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  30.4%, 72.6% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  80.4% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-10 {
  22.6% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  30.4%, 72.6% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  80.4% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-11 {
  24.46% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  32.14%, 74.46% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  82.14% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-11 {
  24.46% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  32.14%, 74.46% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  82.14% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-12 {
  26.32% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  33.88%, 76.32% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  83.88% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-12 {
  26.32% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  33.88%, 76.32% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  83.88% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-13 {
  28.18% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  35.62%, 78.18% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  85.62% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-13 {
  28.18% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  35.62%, 78.18% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  85.62% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-14 {
  30.04% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  37.36%, 80.04% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  87.36% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-14 {
  30.04% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  37.36%, 80.04% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  87.36% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-15 {
  31.9% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  39.1%, 81.9% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  89.1% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-15 {
  31.9% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  39.1%, 81.9% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  89.1% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-16 {
  33.76% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  40.84%, 83.76% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  90.84% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-16 {
  33.76% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  40.84%, 83.76% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  90.84% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-17 {
  35.62% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  42.58%, 85.62% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  92.58% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-17 {
  35.62% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  42.58%, 85.62% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  92.58% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-18 {
  37.48% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  44.32%, 87.48% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  94.32% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-18 {
  37.48% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  44.32%, 87.48% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  94.32% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes left {
  4% {
    transform: rotateZ(90deg);
  }
  10%, 40% {
    transform: rotateZ(0deg);
  }
  46%, 54% {
    transform: rotateZ(90deg);
  }
  60%, 90% {
    transform: rotateZ(0deg);
  }
  96% {
    transform: rotateZ(90deg);
  }
}
@keyframes left {
  4% {
    transform: rotateZ(90deg);
  }
  10%, 40% {
    transform: rotateZ(0deg);
  }
  46%, 54% {
    transform: rotateZ(90deg);
  }
  60%, 90% {
    transform: rotateZ(0deg);
  }
  96% {
    transform: rotateZ(90deg);
  }
}
@-webkit-keyframes right {
  4% {
    transform: rotateZ(-90deg);
  }
  10%, 40% {
    transform: rotateZ(0deg);
  }
  46%, 54% {
    transform: rotateZ(-90deg);
  }
  60%, 90% {
    transform: rotateZ(0deg);
  }
  96% {
    transform: rotateZ(-90deg);
  }
}
@keyframes right {
  4% {
    transform: rotateZ(-90deg);
  }
  10%, 40% {
    transform: rotateZ(0deg);
  }
  46%, 54% {
    transform: rotateZ(-90deg);
  }
  60%, 90% {
    transform: rotateZ(0deg);
  }
  96% {
    transform: rotateZ(-90deg);
  }
}
html {
  box-sizing: border-box;
  -webkit-font-smoothing: antialiased;
}

* {
  box-sizing: inherit;
}
*:before, *:after {
  box-sizing: inherit;
}

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #275EFE;
}

<div class="book">
  <div class="inner">
    <div class="left"></div>
    <div class="middle"></div>
    <div class="right"></div>
  </div>
  <ul>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
  </ul>
</div>

The source where I took this from is https://codepen.io/aaroniker/pen/zYOewEP

What I did to the original, was to remove the base transform as it was causing some undesired behavior when pausing the animation at the beginning (it is sometimes needed).

.book {
  --color: #fff;
  --duration: 6.8s;
  width: 32px;
  height: 12px;
  position: relative;
  margin: 32px 0 0 0;
  zoom: 1.5;
}
.book .inner {
  width: 32px;
  height: 12px;
  position: relative;
}
.book .inner .left,
.book .inner .right {
  width: 60px;
  height: 4px;
  top: 0;
  border-radius: 2px;
  background: var(--color);
  position: absolute;
}
.book .inner .left:before,
.book .inner .right:before {
  content: "";
  width: 48px;
  height: 4px;
  border-radius: 2px;
  background: inherit;
  position: absolute;
  top: -10px;
  left: 6px;
}
.book .inner .left {
  right: 28px;
  transform-origin: 58px 2px;
  transform: rotateZ(90deg);
  -webkit-animation: left var(--duration) ease infinite;
          animation: left var(--duration) ease infinite;
}
.book .inner .right {
  left: 28px;
  transform-origin: 2px 2px;
  transform: rotateZ(-90deg);
  -webkit-animation: right var(--duration) ease infinite;
          animation: right var(--duration) ease infinite;
}
.book .inner .middle {
  width: 32px;
  height: 12px;
  border: 4px solid var(--color);
  border-top: 0;
  border-radius: 0 0 9px 9px;
  transform: translateY(2px);
}
.book ul {
  margin: 0;
  padding: 0;
  list-style: none;
  position: absolute;
  left: 50%;
  top: 0;
}
.book ul li {
  height: 4px;
  border-radius: 2px;
  transform-origin: 100% 2px;
  width: 48px;
  right: 0;
  top: -10px;
  position: absolute;
  background: var(--color);
  transform: rotateZ(0deg) translateX(-18px);
  -webkit-animation-duration: var(--duration);
          animation-duration: var(--duration);
  -webkit-animation-timing-function: ease;
          animation-timing-function: ease;
  -webkit-animation-iteration-count: infinite;
          animation-iteration-count: infinite;
}
.book ul li:nth-child(0) {
  -webkit-animation-name: page-0;
          animation-name: page-0;
}
.book ul li:nth-child(1) {
  -webkit-animation-name: page-1;
          animation-name: page-1;
}
.book ul li:nth-child(2) {
  -webkit-animation-name: page-2;
          animation-name: page-2;
}
.book ul li:nth-child(3) {
  -webkit-animation-name: page-3;
          animation-name: page-3;
}
.book ul li:nth-child(4) {
  -webkit-animation-name: page-4;
          animation-name: page-4;
}
.book ul li:nth-child(5) {
  -webkit-animation-name: page-5;
          animation-name: page-5;
}
.book ul li:nth-child(6) {
  -webkit-animation-name: page-6;
          animation-name: page-6;
}
.book ul li:nth-child(7) {
  -webkit-animation-name: page-7;
          animation-name: page-7;
}
.book ul li:nth-child(8) {
  -webkit-animation-name: page-8;
          animation-name: page-8;
}
.book ul li:nth-child(9) {
  -webkit-animation-name: page-9;
          animation-name: page-9;
}
.book ul li:nth-child(10) {
  -webkit-animation-name: page-10;
          animation-name: page-10;
}
.book ul li:nth-child(11) {
  -webkit-animation-name: page-11;
          animation-name: page-11;
}
.book ul li:nth-child(12) {
  -webkit-animation-name: page-12;
          animation-name: page-12;
}
.book ul li:nth-child(13) {
  -webkit-animation-name: page-13;
          animation-name: page-13;
}
.book ul li:nth-child(14) {
  -webkit-animation-name: page-14;
          animation-name: page-14;
}
.book ul li:nth-child(15) {
  -webkit-animation-name: page-15;
          animation-name: page-15;
}
.book ul li:nth-child(16) {
  -webkit-animation-name: page-16;
          animation-name: page-16;
}
.book ul li:nth-child(17) {
  -webkit-animation-name: page-17;
          animation-name: page-17;
}
.book ul li:nth-child(18) {
  -webkit-animation-name: page-18;
          animation-name: page-18;
}

@-webkit-keyframes page-0 {
  4% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  13%, 54% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  63% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}

@keyframes page-0 {
  4% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  13%, 54% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  63% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-1 {
  5.86% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  14.74%, 55.86% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  64.74% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-1 {
  5.86% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  14.74%, 55.86% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  64.74% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-2 {
  7.72% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  16.48%, 57.72% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  66.48% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-2 {
  7.72% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  16.48%, 57.72% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  66.48% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-3 {
  9.58% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  18.22%, 59.58% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  68.22% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-3 {
  9.58% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  18.22%, 59.58% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  68.22% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-4 {
  11.44% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  19.96%, 61.44% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  69.96% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-4 {
  11.44% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  19.96%, 61.44% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  69.96% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-5 {
  13.3% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  21.7%, 63.3% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  71.7% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-5 {
  13.3% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  21.7%, 63.3% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  71.7% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-6 {
  15.16% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  23.44%, 65.16% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  73.44% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-6 {
  15.16% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  23.44%, 65.16% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  73.44% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-7 {
  17.02% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  25.18%, 67.02% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  75.18% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-7 {
  17.02% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  25.18%, 67.02% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  75.18% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-8 {
  18.88% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  26.92%, 68.88% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  76.92% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-8 {
  18.88% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  26.92%, 68.88% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  76.92% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-9 {
  20.74% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  28.66%, 70.74% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  78.66% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-9 {
  20.74% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  28.66%, 70.74% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  78.66% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-10 {
  22.6% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  30.4%, 72.6% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  80.4% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-10 {
  22.6% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  30.4%, 72.6% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  80.4% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-11 {
  24.46% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  32.14%, 74.46% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  82.14% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-11 {
  24.46% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  32.14%, 74.46% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  82.14% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-12 {
  26.32% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  33.88%, 76.32% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  83.88% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-12 {
  26.32% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  33.88%, 76.32% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  83.88% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-13 {
  28.18% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  35.62%, 78.18% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  85.62% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-13 {
  28.18% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  35.62%, 78.18% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  85.62% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-14 {
  30.04% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  37.36%, 80.04% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  87.36% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-14 {
  30.04% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  37.36%, 80.04% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  87.36% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-15 {
  31.9% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  39.1%, 81.9% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  89.1% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-15 {
  31.9% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  39.1%, 81.9% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  89.1% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-16 {
  33.76% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  40.84%, 83.76% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  90.84% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-16 {
  33.76% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  40.84%, 83.76% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  90.84% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-17 {
  35.62% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  42.58%, 85.62% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  92.58% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-17 {
  35.62% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  42.58%, 85.62% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  92.58% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes page-18 {
  37.48% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  44.32%, 87.48% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  94.32% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@keyframes page-18 {
  37.48% {
    transform: rotateZ(0deg) translateX(-18px);
  }
  44.32%, 87.48% {
    transform: rotateZ(180deg) translateX(-18px);
  }
  94.32% {
    transform: rotateZ(0deg) translateX(-18px);
  }
}
@-webkit-keyframes left {
  4% {
    transform: rotateZ(90deg);
  }
  10%, 40% {
    transform: rotateZ(0deg);
  }
  46%, 54% {
    transform: rotateZ(90deg);
  }
  60%, 90% {
    transform: rotateZ(0deg);
  }
  96% {
    transform: rotateZ(90deg);
  }
}
@keyframes left {
  4% {
    transform: rotateZ(90deg);
  }
  10%, 40% {
    transform: rotateZ(0deg);
  }
  46%, 54% {
    transform: rotateZ(90deg);
  }
  60%, 90% {
    transform: rotateZ(0deg);
  }
  96% {
    transform: rotateZ(90deg);
  }
}
@-webkit-keyframes right {
  4% {
    transform: rotateZ(-90deg);
  }
  10%, 40% {
    transform: rotateZ(0deg);
  }
  46%, 54% {
    transform: rotateZ(-90deg);
  }
  60%, 90% {
    transform: rotateZ(0deg);
  }
  96% {
    transform: rotateZ(-90deg);
  }
}
@keyframes right {
  4% {
    transform: rotateZ(-90deg);
  }
  10%, 40% {
    transform: rotateZ(0deg);
  }
  46%, 54% {
    transform: rotateZ(-90deg);
  }
  60%, 90% {
    transform: rotateZ(0deg);
  }
  96% {
    transform: rotateZ(-90deg);
  }
}
html {
  box-sizing: border-box;
  -webkit-font-smoothing: antialiased;
}

* {
  box-sizing: inherit;
}
*:before, *:after {
  box-sizing: inherit;
}

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #275EFE;
}

<div class="book">
  <div class="inner">
    <div class="left"></div>
    <div class="middle"></div>
    <div class="right"></div>
  </div>
  <ul>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
  </ul>
</div>

Share Improve this question asked Feb 5 at 21:44 victim 671 silver badge7 bronze badges

What is the problem? The horizontal white strips on the left and right of the closed book? When a book is open, they represent two parts of the pages. But this does not realistic anyway, as the widths of the parts don't change. So, does it worth the effort? These days, nobody could be impressed with this kind of animation. :-( And the bug looks simple, you just forgot to move an element when closing a book. – Sergey A Kryukov Commented Feb 5 at 23:37
1 Oh, I just looked at the source you provided. What can I see? 1) The code is not yours, 2) The code does not show the same bug we can see on your snippet => You did not reproduce already working code. Then why do you ask your question? You already have the answer. – Sergey A Kryukov Commented Feb 5 at 23:43
2 It looks like the author of the original code is Aaron Iker. Even though it is possible to find out who published the source you use, I think this is not enough: you did not mention his name explicitly, and you did not explicitly give him a credit for this material. For more information, please see the referencing rules. – Sergey A Kryukov Commented Feb 5 at 23:49
The animation in the original is a bit weird, the pages turn outside the book. Is that what you want? – A Haworth Commented Feb 6 at 14:23

Add a comment |

1 Answer 1

Sorted by: Reset to default 0

In your code, you can add all the element keyframes for the left, right, and middle. However, you forgot the main book.inner keyframe animation and did not use it from the book.inner div.

While all the list items are functioning properly, the main book section animation is broken.

Therefore, I added the keyframe and utilized it from the book.inner div as per the provided CodePen example.

html {
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
}

* {
    box-sizing: inherit;
}

*:before,
*:after {
    box-sizing: inherit;
}

body {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: #275EFE;
}

.book {
    --color: #fff;
    --duration: 6.8s;
    width: 32px;
    height: 12px;
    position: relative;
    margin: 32px 0 0 0;
    //Demo
    zoom: 1.5;
}

.book .inner {
    width: 32px;
    height: 12px;
    position: relative;
    transform-origin: 2px 2px;
    transform: rotateZ(-90deg);
    animation: book var(--duration) ease infinite;
}

.book .inner .left,
.book .inner .right {
    width: 60px;
    height: 4px;
    top: 0;
    border-radius: 2px;
    background: var(--color);
    position: absolute;
}

.book .inner .left:before,
.book .inner .right:before {
    content: '';
    width: 48px;
    height: 4px;
    border-radius: 2px;
    background: inherit;
    position: absolute;
    top: -10px;
    left: 6px;
}

.book .inner .left {
    right: 28px;
    transform-origin: 58px 2px;
    transform: rotateZ(90deg);
    animation: left var(--duration) ease infinite;
}

.book .inner .right {
    left: 28px;
    transform-origin: 2px 2px;
    transform: rotateZ(-90deg);
    animation: right var(--duration) ease infinite;
}

.book .inner .middle {
    width: 32px;
    height: 12px;
    border: 4px solid var(--color);
    border-top: 0;
    border-radius: 0 0 9px 9px;
    transform: translateY(2px);
}

.book ul {
    margin: 0;
    padding: 0;
    list-style: none;
    position: absolute;
    left: 50%;
    top: 0;
}

.book ul li {
    height: 4px;
    border-radius: 2px;
    transform-origin: 100% 2px;
    width: 48px;
    right: 0;
    top: -10px;
    position: absolute;
    background: var(--color);
    transform: rotateZ(0deg) translateX(-18px);
    animation-duration: var(--duration);
    animation-timing-function: ease;
    animation-iteration-count: infinite;
}

.book ul li:nth-child(0) {
    animation-name: page-0;
}

.book ul li:nth-child(1) {
    animation-name: page-1;
}

.book ul li:nth-child(2) {
    animation-name: page-2;
}

.book ul li:nth-child(3) {
    animation-name: page-3;
}

.book ul li:nth-child(4) {
    animation-name: page-4;
}

.book ul li:nth-child(5) {
    animation-name: page-5;
}

.book ul li:nth-child(6) {
    animation-name: page-6;
}

.book ul li:nth-child(7) {
    animation-name: page-7;
}

.book ul li:nth-child(8) {
    animation-name: page-8;
}

.book ul li:nth-child(9) {
    animation-name: page-9;
}

.book ul li:nth-child(10) {
    animation-name: page-10;
}

.book ul li:nth-child(11) {
    animation-name: page-11;
}

.book ul li:nth-child(12) {
    animation-name: page-12;
}

.book ul li:nth-child(13) {
    animation-name: page-13;
}

.book ul li:nth-child(14) {
    animation-name: page-14;
}

.book ul li:nth-child(15) {
    animation-name: page-15;
}

.book ul li:nth-child(16) {
    animation-name: page-16;
}

.book ul li:nth-child(17) {
    animation-name: page-17;
}

.book ul li:nth-child(18) {
    animation-name: page-18;
}

@keyframes page-0 {
    4% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    13%,
    54% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    63% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-1 {
    5.86% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    14.74%,
    55.86% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    64.74% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-2 {
    7.72% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    16.48%,
    57.72% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    66.48% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-3 {
    9.58% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    18.22%,
    59.58% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    68.22% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-4 {
    11.44% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    19.96%,
    61.44% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    69.96% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-5 {
    13.3% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    21.7%,
    63.3% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    71.7% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-6 {
    15.16% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    23.44%,
    65.16% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    73.44% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-7 {
    17.02% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    25.18%,
    67.02% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    75.18% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-8 {
    18.88% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    26.92%,
    68.88% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    76.92% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-9 {
    20.74% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    28.66%,
    70.74% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    78.66% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-10 {
    22.6% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    30.4%,
    72.6% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    80.4% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-11 {
    24.46% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    32.14%,
    74.46% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    82.14% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-12 {
    26.32% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    33.88%,
    76.32% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    83.88% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-13 {
    28.18% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    35.62%,
    78.18% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    85.62% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-14 {
    30.04% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    37.36%,
    80.04% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    87.36% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-15 {
    31.9% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    39.1%,
    81.9% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    89.1% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-16 {
    33.76% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    40.84%,
    83.76% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    90.84% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-17 {
    35.62% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    42.58%,
    85.62% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    92.58% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes page-18 {
    37.48% {
        transform: rotateZ(0deg) translateX(-18px);
    }

    44.32%,
    87.48% {
        transform: rotateZ(180deg) translateX(-18px);
    }

    94.32% {
        transform: rotateZ(0deg) translateX(-18px);
    }
}

@keyframes left {
    4% {
        transform: rotateZ(90deg);
    }

    10%,
    40% {
        transform: rotateZ(0deg);
    }

    46%,
    54% {
        transform: rotateZ(90deg);
    }

    60%,
    90% {
        transform: rotateZ(0deg);
    }

    96% {
        transform: rotateZ(90deg);
    }
}

@keyframes right {
    4% {
        transform: rotateZ(-90deg);
    }

    10%,
    40% {
        transform: rotateZ(0deg);
    }

    46%,
    54% {
        transform: rotateZ(-90deg);
    }

    60%,
    90% {
        transform: rotateZ(0deg);
    }

    96% {
        transform: rotateZ(-90deg);
    }
}

@keyframes book {
    4% {
        transform: rotateZ(-90deg);
    }

    10%,
    40% {
        transform: rotateZ(0deg);
        transform-origin: 2px 2px;
    }

    40.01%,
    59.99% {
        transform-origin: 30px 2px;
    }

    46%,
    54% {
        transform: rotateZ(90deg);
    }

    60%,
    90% {
        transform: rotateZ(0deg);
        transform-origin: 2px 2px;
    }

    96% {
        transform: rotateZ(-90deg);
    }
}

<div class="book">
    <div class="inner">
        <div class="left"></div>
        <div class="middle"></div>
        <div class="right"></div>
    </div>
    <ul>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
    </ul>
</div>

科技改变生活-雨落星辰 - 所有的伟大,都源于一个勇敢的开始

html - Fix pure CSS book animation - Stack Overflow

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