button {
  background: transparent;
  cursor: pointer;
}

button:hover {
  background: rgba(0, 0, 0, 0.2);
}

.wrapper {
  width: 1240px;
  height: 720px;
  margin: 5rem auto;
  color: #34495e;
  -webkit-transform-style: preserve-3d;
  transform-style: preserve-3d;
  -webkit-perspective: 1800px;
  perspective: 1800px;
}

.wrapper ol {
  padding-left: 20px;
  margin: 0;
}

.wrapper .section-wrap {
  position: relative;
}

.wrapper a {
  color: #4395ff;
  text-shadow: 0 0 0 transparent;
}

.wrapper a::after {
  background: #4395ff;
}

.wrapper h4 {
  margin-top: 20px;
}

.wrapper .left, .wrapper .middle, .wrapper .right {
  width: 33.333333%;
  height: 100%;
  float: left;
  background: #e2e5f2;
  border-radius: 10px;
}

.wrapper .left {
  position: relative;
}

.wrapper .left {
  -webkit-transform-origin: 100% 50%;
  transform-origin: 100% 50%;
  -webkit-transform: rotateY(180deg);
  transform: rotateY(180deg);
  z-index: 2;
  -webkit-transform-style: preserve-3d;
  transform-style: preserve-3d;
  -webkit-transition: -webkit-transform .8s;
  transition: -webkit-transform .8s;
  transition: transform .8s;
  transition: transform .8s, -webkit-transform .8s;
}

.wrapper .left .page, .wrapper .left .back {
  width: 100%;
  height: 100%;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
  position: absolute;
  top: 0;
  left: 0;
  border-radius: 10px;
}

.wrapper .left .page {
  padding: 40px;
  -webkit-transform: translateZ(-0.1px) rotateY(180deg);
  transform: translateZ(-0.1px) rotateY(180deg);
  background: #e2e5f2;
  z-index: 5;
}

.wrapper .left .page .section-wrap {
  height: 100%;
}

.wrapper .left .page .open {
  position: absolute;
  padding: 5px;
  border: 2px solid rgba(0, 0, 0, 0.5);
  bottom: 0;
  right: 0;
}

.wrapper .left .page .logo {
  position: absolute;
  top: 30%;
  left: 50%;
  -webkit-transform: translateX(-50%);
  transform: translateX(-50%);
  width: 90%;
}

.wrapper .left .page .author {
  position: absolute;
  right: 0;
  bottom: 10%;
}

.wrapper .left .back {
  -webkit-transform: translateZ(0.1px) rotateY(0);
  transform: translateZ(0.1px) rotateY(0);
  z-index: 4;
  background: #e2e5f2;
  padding: 20px;
}

.wrapper .middle, .wrapper .right {
  padding: 20px;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

.wrapper .middle {
  -webkit-transform: translateZ(-0.1px);
  transform: translateZ(-0.1px);
  border-left: 1px solid #ccc;
  border-right: 1px solid #ccc;
  box-sizing: border-box;
}

.wrapper .right {
  -webkit-transform-origin: 0 50%;
  transform-origin: 0 50%;
  -webkit-transform: rotateY(-180deg);
  transform: rotateY(-180deg);
  -webkit-transition: -webkit-transform .8s;
  transition: -webkit-transform .8s;
  transition: transform .8s;
  transition: transform .8s, -webkit-transform .8s;
  -webkit-transform-style: preserve-3d;
  transform-style: preserve-3d;
  position: relative;
}

.wrapper .right .page, .wrapper .right .back {
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  padding: 20px;
  background: #e2e5f2;
  border-radius: 10px;
}

.wrapper .right .page {
  -webkit-transform: translateZ(0.1px) rotateY(180deg);
  transform: translateZ(0.1px) rotateY(180deg);
}

.wrapper .right .back {
  -webkit-transform: translateZ(0.2px) rotateY(0);
  transform: translateZ(0.2px) rotateY(0);
}

.wrapper .right .close {
  position: absolute;
  width: 25px;
  height: 25px;
  font-size: 18px;
  right: 20px;
  top: 20px;
}