.menu{
    width: 100%;
    /* height: fit; */
    display: flex;
    justify-content: center;
    position: relative;
}

.book {
    width: 100%;
    height: fit-content;  
    display: flex;
    width: 100%;
    justify-content: flex-end;
    margin-top: 20px;
    flex-wrap: wrap;
  }
  #cover {
    width: 200px;
    height: 400px;
  }
  .flip-book {
    width: 50%;
    height: 600px;
    /* width: 250px;
    height: 400px; */
    position: relative;
    perspective: 1500px;
  }
  .flip {
    width: 90%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    transform-origin: left;
    transform-style: preserve-3d;
    transform: rotateY(0deg);
    transition: 1s;
    color: #000;
    
  }
  .front {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    background-color:#F4EBD0;
    box-sizing: border-box;
    padding: 0 13px;
    border-radius: 10px;
  }
  .back {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: 99;
    transform: rotateY(180deg);
    backface-visibility: hidden;
    background-color: #B68D40;
    border-radius: 10px;
  }
  .next-btn {
    position: absolute;
    bottom: 13px;
    right: 13px;
    cursor: pointer;
    background-color: #B68D40;
    padding: 5px;
    color: #000;
    font-size: 1rem;
    border-radius: 15px;
  }
  .back-btn {
    position: absolute;
    bottom: 13px;
    right: 13px;
    cursor: pointer;
    background-color: #F4EBD0;
    padding: 5px;
    color: #000;
    font-size: 1rem;
    border-radius: 15px;
  }
  #p1 {
    z-index: 3;
  }
  #p2 {
    z-index: 2;
  }
  #p3 {
    z-index: 1;
  }
  #c1:checked ~ .flip-book #p1 {
    transform: rotateY(-180deg);
    z-index: 1;
  }
  #c2:checked ~ .flip-book #p2 {
    transform: rotateY(-180deg);
    z-index: 2;
  }
  #c3:checked ~ .flip-book #p3 {
    transform: rotateY(-180deg);
    z-index: 3;
  }

  input[type="checkbox"] {
    display: none;
}