/* ページめくり */

@media screen and (max-width: 768px) {
  .book {
    max-width: 90vw; /* 画面幅の90%に収める */
    transform: none !important; /* 右寄せを解除 強制的に解除 */
    margin: 0 auto; /* 中央寄せに戻す */
  }
    
    body {
    overflow-x: hidden;
  }
}


.book {
  position: relative;
  width: 100%;
  max-width: 660px;
  box-sizing: border-box;
  height: auto;
  aspect-ratio: 2 / 3;
  margin: 0 auto;
  transform: translateX(60px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
  padding: 10px;
  background: #fff;
}

  .page {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #fff;
    border: 1px solid #ccc;
    transform-origin: left center;
    transition: transform 0.8s ease;   
  }

.page img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

.text-content {
  padding: 60px;
  font-size: 16px;
  line-height: 2;
  color: #333;
  height: 100%;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.page:nth-child(1){
  z-index:20;
}
.page:nth-child(2){
  z-index:19;
}
.page:nth-child(3){
  z-index:18;
}
.page:nth-child(4){
  z-index:17;
}
.page:nth-child(5){
  z-index:16;
}
.page:nth-child(6){
  z-index:15;
}
.page:nth-child(7){
  z-index:14;
}
.page:nth-child(8){
  z-index:13;
}
.page:nth-child(9){
  z-index:12;
}
.page:nth-child(10){
  z-index:11;
}
.page:nth-child(11){
  z-index:10;
}
.page:nth-child(12){
  z-index:9;
}
.page:nth-child(13){
  z-index:8;
}
.page:nth-child(14){
  z-index:7;
}
.page:nth-child(15){
  z-index:6;
}
.page:nth-child(16){
  z-index:5;
}
.page:nth-child(17){
  z-index:4;
}
.page:nth-child(18){
  z-index:3;
}
.page:nth-child(19){
  z-index:2;
}
.page:nth-child(20){
  z-index:1;
}
  .page.flipped {
    transform: rotateY(-180deg);
    z-index: -1;
  }

/* footer */
#bookfooternav {
    width: 30%;
    height: 30px;
    text-align: center;
    font-size: 1em;
    padding-top: 20px;
    margin: 0 auto;
    display: flex;
}