.f-flipbook {
  display: inline-block;
  position: relative;
  margin: 20px 0px 30px 0px;
}

.flipbook {
  margin: auto !important;
}

.f-flipbook button {
  position: absolute;
  top: 50%;
  border: none;
  background: var(--color-main);
  width: 35px;
  height: 35px;
  color: #fff;
  border-radius: 50%;
  z-index: 1;
}

.f-flipbook .turn-next {
  left: calc(100% + 60px);
  left: -moz-calc(100% + 60px);
  left: -webkit-calc(100% - 60px);
}

.f-flipbook .turn-prev {
  right: calc(100% + 60px);
  right: -moz-calc(100% + 60px);
  right: -webkit-calc(100% - 60px);
}

.f-flipbook:before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  background: url(../images/photo/khung-book.png) no-repeat top center;
  background-size: 100% 100%;
}

.flipbook-viewport .page {
  width: 461px;
  height: 600px;
  background-color: #fff;
  background-repeat: no-repeat;
  background-size: 100% 100%;
}

.flipbook .page {
  -webkit-box-shadow: 0 0 20px rgba(0, 0, 0, 0.2);
  -moz-box-shadow: 0 0 20px rgba(0, 0, 0, 0.2);
  -ms-box-shadow: 0 0 20px rgba(0, 0, 0, 0.2);
  -o-box-shadow: 0 0 20px rgba(0, 0, 0, 0.2);
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.2);
}

.flipbook-viewport .page img {
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  margin: 0;
}

.flipbook-viewport .shadow {
  -webkit-transition: -webkit-box-shadow 0.5s;
  -moz-transition: -moz-box-shadow 0.5s;
  -o-transition: -webkit-box-shadow 0.5s;
  -ms-transition: -ms-box-shadow 0.5s;
  -webkit-box-shadow: 0 0 20px #ccc;
  -moz-box-shadow: 0 0 20px #ccc;
  -o-box-shadow: 0 0 20px #ccc;
  -ms-box-shadow: 0 0 20px #ccc;
  box-shadow: 0 0 20px #ccc;
}