/* =========================
   A4 cover in section1
   ========================= */
.lb-a4{
  background: #fff;
  /* border: 1px solid var(--border); */
  border-radius: 0;
  overflow: hidden;
  aspect-ratio: 210 / 297;
  display: block;

}
.lb-a4 img{
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}
.lb-a4--main{
  width: min(520px, calc(100% - 36px));
  max-width: calc(100% - 36px);
}
.lb-shadow{ box-shadow: none; }

.lb-center{
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
  padding: 18px;
  min-width: 0;
}

/* =========================================================
   SECTION 1: Title / Subtitle under cover image
   ========================================================= */
/* ADDED */
.lb-cover-stack{
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 50px;
}

.lb-cover-meta{
  text-align: center;
  line-height: 1.15;
}

.lb-cover-title{
  font-size: 20px;
  letter-spacing: 5.5px;
  color: var(--text);
}

.lb-cover-subtitle{
  margin-top: 25px;
  font-size: 11px;
  letter-spacing: 0.15px;
  color: var(--muted);
  white-space: pre-line;
  line-height: 1.35;
}

/* =========================================================
   SECTION 2: Chapter thumbnail grid
   - Web: 5 cards in one horizontal row
   - Tablet: 3 cards in one horizontal row
   - App: 2-column vertical pages
   ========================================================= */
#sec-contents .lb-canvas{
  position: relative;
  display: flex;
  align-items: flex-end;
  justify-content: stretch;
  background: #fff;
}

.lb-contents-grid{
  width: 100%;
  height: clamp(220px, 33vh, 360px);
  padding: clamp(18px, 2.4vw, 32px) clamp(18px, 2.8vw, 38px);
  display: flex;
  gap: var(--s2-gap);
  align-content: stretch;
  align-items: stretch;
  overflow: hidden;
  min-width: 0;
  min-height: 0;
  scroll-behavior: auto;
  overscroll-behavior: contain;
  scrollbar-width: none;
  -ms-overflow-style: none;
  background-color: #fff;
  background-image:
    repeating-linear-gradient(90deg, rgba(0, 0, 0, 0.03) 0 1px, rgba(255, 255, 255, 0.0) 1px 3px),
    repeating-linear-gradient(0deg, rgba(0, 0, 0, 0.02) 0 1px, rgba(255, 255, 255, 0.0) 1px 3px);
}
.lb-contents-grid::-webkit-scrollbar{ display: none; }

.lb-contents-grid.is-desktop,
.lb-contents-grid.is-tablet{
  flex-direction: row;
  justify-content: flex-start;
  overflow-x: hidden;
  overflow-y: hidden;
}

.lb-contents-grid.is-desktop.is-axis-x,
.lb-contents-grid.is-tablet.is-axis-x{
  overflow-x: auto;
  height: 45vh;
}

.lb-contents-grid.is-mobile{
  width: min(92vw, 760px);
  height: clamp(360px, 60vh, 720px);
  margin: 0 auto;
  padding: clamp(18px, 4.6vw, 28px);
  gap: clamp(16px, 3.3vw, 24px);
  flex-direction: column;
  justify-content: flex-start;
  overflow-x: hidden;
  overflow-y: hidden;
}

.lb-contents-grid.is-mobile.is-axis-y{
  overflow-y: auto;
}

.lb-contents-page{
  flex: 0 0 100%;
  width: 100%;
  height: 100%;
  min-width: 0;
  min-height: 0;
  display: grid;
  gap: var(--s2-gap);
  align-content: stretch;
  align-items: stretch;
  overflow: hidden;
}

.lb-contents-page--desktop{
  grid-template-columns: repeat(5, minmax(0, 1fr));
  grid-template-rows: minmax(0, 1fr);
}

.lb-contents-page--tablet{
  grid-template-columns: repeat(3, minmax(0, 1fr));
  grid-template-rows: minmax(0, 1fr);
}

.lb-contents-page--mobile{
  grid-template-columns: repeat(2, minmax(0, 1fr));
  grid-template-rows: repeat(2, minmax(0, 1fr));
  gap: clamp(16px, 3.3vw, 24px);
}

.lb-tile{
  background: transparent;
  border: none;
  padding: 0;
  overflow: hidden;
  cursor: default;
  display: block;
  min-width: 0;
  min-height: 0;
}
.lb-tile--placeholder{
  visibility: hidden;
  pointer-events: none;
}
/* ✅ focus outline: keyboard only (마우스 클릭 시 검은 사각형 테두리 깜빡임 방지) */
.lb-tile:focus{ outline: none; } /* CHANGED */
.lb-tile:focus-visible{ outline: 1px solid var(--border); outline-offset: 2px; } /* CHANGED */

.lb-tile--chapter{
  height: 100%;
  display: grid;
  grid-template-rows: minmax(0, 1fr) auto;
  gap: 8px;
  min-height: 0;
}

.lb-tile__cover{
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: clamp(8px, 1vw, 14px);
  min-width: 0;
  min-height: 0;
  overflow: hidden;
}
.lb-tile__cover img{
  width: auto;
  height: auto;
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  object-position: center;
  display: block;
  flex: 0 0 auto;
}

.lb-tile__img-trigger{
  cursor: pointer;
  outline: none;
}
.lb-tile__img-trigger:focus-visible{
  outline: 1px solid var(--border);
  outline-offset: 2px;
}

.lb-tile__label{
  font-size: clamp(9px, 0.65vw, 11px);
  letter-spacing: 0.08em;
  text-align: center;
  color: rgba(0, 0, 0, 0.45);
  line-height: 1.15;
  white-space: normal;
  overflow: hidden;
  text-overflow: unset;
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  min-height: 2.2em;
  padding: 0;
  background: transparent;
}

.lb-contents-nav-fixed{
  position: absolute;
  left: 50%;
  top: clamp(18px, 3vh, 38px);
  transform: translateX(-50%);
  width: min(860px, calc(100% - 44px));
  max-height: clamp(84px, 18vh, 180px);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 26px;
  z-index: 26;
  overflow-y: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  justify-items: center;
}
.lb-contents-nav-fixed::-webkit-scrollbar{ display: none; }

.lb-contents-nav__btn{
  appearance: none;
  border: none;
  background: transparent;
  padding: 0;
  margin: 0;
  text-align: center;
  font-size: clamp(11px, 0.78vw, 13px);
  line-height: 1.18;
  letter-spacing: 0.08em;
  color: rgba(0, 0, 0, 0.74);
  cursor: pointer;
  transition: color 150ms ease;
}
.lb-contents-nav__btn:hover{
  color: rgba(0, 0, 0, 0.96);
}
.lb-contents-nav__btn:focus{
  outline: none;
}
.lb-contents-nav__btn:focus-visible{
  outline: 1px solid rgba(0, 0, 0, 0.72);
  outline-offset: 2px;
}

.lb-contents-title-fixed{
  position: absolute;
  left: 50%;
  top: clamp(84px, 12vh, 136px);
  transform: translateX(-50%);
  z-index: 27;
  pointer-events: none;
  writing-mode: horizontal-tb;
  text-orientation: mixed;
  font-size: clamp(13px, 1vw, 16px);
  letter-spacing: 0.2em;
  text-transform: none;
  white-space: nowrap;
  text-align: center;
  color: rgba(0, 0, 0, 0.86);
  padding: 0;
  border: none;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
}

@media (min-width: 1200px){
  .lb-contents-nav-fixed{
    width: min(980px, calc(100% - 120px));
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 9px 155px;
    margin-top: 50px;
  }
  .lb-contents-title-fixed{
    left: clamp(28px, 4.5vw, 74px);
    top: clamp(84px, 12vh, 136px);
    transform: none;
    text-align: left;
  }
}

@media (max-width: 1199px){
  .lb-contents-nav-fixed{
    width: min(760px, calc(100% - 42px));
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 7px 20px;
    margin-top: 50px;
  }
  .lb-contents-title-fixed{
    left: 50%;
    top: clamp(84px, 12vh, 136px);
    transform: translateX(-50%);
    text-align: center;
  }
}

@media (max-width: 760px){
  .lb-contents-nav-fixed{
    width: min(680px, calc(100% - 32px));
    top: clamp(14px, 2.8vh, 24px);
    gap: 6px 14px;
  }
  .lb-contents-nav__btn{
    font-size: 11px;
    letter-spacing: 0.06em;
  }
  .lb-contents-title-fixed{
    top: clamp(74px, 10vh, 114px);
    font-size: 12px;
    letter-spacing: 0.16em;
  }
}

/* =========================================================
   SECTION 3: BOOK VIEWER (CLEAN MAGAZINE LOOK)
   ========================================================= */

/* ✅ 섹션3만 살짝 톤 다운된 배경(그림자 가시성 확보) */
.lb-viewer{
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
  position: relative;
  padding: 18px;
  min-width: 0;

}

.lb-book-shell{
  position: relative;
  width: min(1200px, 100%);
  /*height: min(calc(100% - 24px), 78vh);
  aspect-ratio: 420 / 297; /* spread */
  aspect-ratio: 204 / 145;
}

/* ✅ 아래 큰 그림자: 룩북이 살짝 떠있는 느낌 */
.lb-book-shell::before{
  content: "";
  position: absolute;
  left: 8%;
  right: 8%;
  bottom: -14px;
  height: 22px;
  background: rgba(0,0,0,0.22);
  filter: blur(20px);
  opacity: 0.32;
  z-index: 0;
  transform: translateZ(0);
  pointer-events: none;
}

.lb-book-shell[data-mode="single"]{
  width: min(460px, 94vw);
  aspect-ratio: 210 / 297;
}

.lb-book3d{
  position: absolute;
  inset: 0;
  perspective: 1800px;
  transform-style: preserve-3d;
  -webkit-transform-style: preserve-3d;
  z-index: 1;

  --sl: min(var(--stackL), 0);
  --sr: min(var(--stackR), 0);
}

/* ===== stacks behind (shadow separation) ===== */
.lb-book3d__stack{
  position: absolute;
  top: 0;
  bottom: 0;
  border: none;              /* ✅ border 제거 */
  border-radius: 0;          /* ✅ radius 제거 */
  pointer-events: none;
  opacity: 0.98;
  z-index: 1;
  transition: transform 520ms cubic-bezier(0.2, 0.8, 0.15, 1);
  transform: translateZ(var(--zf));

  /* ✅ 스택은 "구분선" 대신 "그림자"로 레이어 느낌 */
  box-shadow:
    0 10px 30px rgba(0,0,0,0.10),
    0 22px 70px rgba(0,0,0,0.12);
}

/* ✅ 기존 종이 엣지 라인 제거 */
.lb-book3d__stack::after{ content: none; }

.lb-book3d[data-mode="spread"] .lb-book3d__stack{ width: 50%; }
.lb-book3d[data-mode="single"] .lb-book3d__stack{ width: 100%; }

.lb-book3d__stack--left{ left: 0; }
.lb-book3d__stack--right{ right: 0; }

/* 스택 방향별로 그림자 방향/깊이 차등 */
.lb-book3d__stack--left{
  box-shadow:
    -8px 10px 26px rgba(0,0,0,0.08),
    -18px 26px 60px rgba(0,0,0,0.10);
}
.lb-book3d__stack--right{
  box-shadow:
    8px 10px 26px rgba(0,0,0,0.08),
    18px 26px 60px rgba(0,0,0,0.10);
}

.lb-book3d[data-mode="spread"] .lb-book3d__stack--left{
  transform:
    translateZ(var(--zf))
    translateX(calc(var(--sl) * var(--stackUnit) * -1))
    translateY(calc(var(--sl) * 0.32 * var(--stackUnit)));
}
.lb-book3d[data-mode="spread"] .lb-book3d__stack--right{
  transform:
    translateZ(var(--zf))
    translateX(calc(var(--sr) * var(--stackUnit)))
    translateY(calc(var(--sr) * 0.32 * var(--stackUnit)));
}
.lb-book3d[data-mode="single"] .lb-book3d__stack--left{
  transform:
    translateZ(var(--zf))
    translateX(calc(var(--sl) * var(--stackUnit) * -0.6))
    translateY(calc(var(--sl) * 0.32 * var(--stackUnit)));
}
.lb-book3d[data-mode="single"] .lb-book3d__stack--right{
  transform:
    translateZ(var(--zf))
    translateX(calc(var(--sr) * var(--stackUnit) * 0.6))
    translateY(calc(var(--sr) * 0.32 * var(--stackUnit)));
}

/* 모바일 single은 책 스택 대신 카드 전환에 집중 */
.lb-book3d[data-mode="single"] .lb-book3d__stack{
  display: none;
}

/* ===== spread/pages ===== */
.lb-book3d__spread{
  position: absolute;
  inset: 0;
  z-index: 6;
  display: grid;
  grid-template-columns: 1fr 1fr;
  transform-style: preserve-3d;
  -webkit-transform-style: preserve-3d;

  /* ✅ 현재 펼쳐진 책도 그림자로 분리 */
  filter: drop-shadow(0 14px 34px rgba(0,0,0,0.14)) drop-shadow(0 34px 90px rgba(0,0,0,0.10));
}

.lb-book3d[data-mode="single"] .lb-book3d__spread{
  grid-template-columns: 1fr;
}


/* =========================
   Edge single (spread mode)
   - cover(0.png) / last page는 "한 장만" 보이되,
     '두 장 펼쳤을 때의 좌/우 자리(레이아웃)'는 그대로 유지 (중앙 이동 없음)
   - 구현: 빈 면을 display:none으로 빼지 않고 visibility:hidden으로 숨겨
     2칸(grid) 자체는 유지한다.
   ========================= */

/* FIXED: (이전 버전의 flex/center 규칙이 있더라도) spread 레이아웃을 강제로 유지 */
.lb-book3d[data-mode="spread"][data-edge="cover"] .lb-book3d__spread,
.lb-book3d[data-mode="spread"][data-edge="last"] .lb-book3d__spread{
  display: grid !important;            /* FIXED */
  grid-template-columns: 1fr 1fr;      /* FIXED */
}

/* FIXED: cover/last에서도 page/stack/sheet 위치가 좌우 원래 자리에서 변하지 않도록 reset */
.lb-book3d[data-mode="spread"][data-edge="cover"] .lb-book3d__page--right,
.lb-book3d[data-mode="spread"][data-edge="last"] .lb-book3d__page--left{
  width: auto !important;              /* FIXED */
  flex: initial !important;            /* FIXED */
}
.lb-book3d[data-mode="spread"][data-edge="cover"] .lb-book3d__stack--left,
.lb-book3d[data-mode="spread"][data-edge="last"] .lb-book3d__stack--right{
  display: block !important;           /* FIXED */
}
.lb-book3d[data-mode="spread"][data-edge="cover"] .lb-book3d__stack--right{
  left: auto !important;               /* FIXED */
  right: 0 !important;                 /* FIXED */
  width: 50% !important;               /* FIXED */
}
.lb-book3d[data-mode="spread"][data-edge="last"] .lb-book3d__stack--left{
  left: 0 !important;                  /* FIXED */
  right: auto !important;              /* FIXED */
  width: 50% !important;               /* FIXED */
}
.lb-book3d[data-mode="spread"][data-edge="cover"] .lb-sheet--next{
  left: 50% !important;                /* FIXED */
}
.lb-book3d[data-mode="spread"][data-edge="last"] .lb-sheet--prev{
  left: 0 !important;                  /* FIXED */
}

/* CHANGED: 빈 면은 "공간은 유지"하고 "시각적으로만" 숨김 (레이아웃 고정) */
.lb-book3d[data-mode="spread"][data-edge="cover"] .lb-book3d__page--left{
  visibility: hidden;                  /* CHANGED */
  pointer-events: none;                /* ADDED */
}
.lb-book3d[data-mode="spread"][data-edge="last"] .lb-book3d__page--right{
  visibility: hidden;                  /* CHANGED */
  pointer-events: none;                /* ADDED */
}

/* ADDED: edge에서 blank opacity(0.06) 잔상이 보일 경우까지 완전 제거 */
.lb-book3d[data-mode="spread"][data-edge="cover"] .lb-book3d__page--left.is-blank,
.lb-book3d[data-mode="spread"][data-edge="last"] .lb-book3d__page--right.is-blank{
  opacity: 0 !important;               /* ADDED */
}

.lb-book3d__page{
  position: relative;
  background: #ffffff;
  border: none;              /* ✅ border 제거 */
  border-radius: 0;          /* ✅ radius 제거 */
  overflow: hidden;
  display: grid;
  place-items: center;
  transform: translateZ(calc(var(--zf) * 2));
}

.lb-book3d__page img{
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

.lb-book3d__page.is-blank{ opacity: 0.06; }
.lb-book3d__page.is-blank img{ display: none; }
.lb-book3d__page.is-empty{
  visibility: hidden;
  pointer-events: none;
}

.lb-book3d__page--left,
.lb-book3d__page--right{
  border-radius: 0;
}

/* ✅ 중앙 회색 라인/스파인 제거 */
.lb-book3d__spine{ display: none; }

/* ✅ 중앙 느낌은 "라인"이 아니라 아주 부드러운 인셋 그림자로만 */
.lb-book3d__page--left{
  box-shadow:
    inset -26px 0 46px rgba(0,0,0,0.04);
}
.lb-book3d__page--right{
  box-shadow:
    inset 26px 0 46px rgba(0,0,0,0.04);
}

/* 기존 중앙 그라데이션(라인처럼 보이던 요소) 제거 */
.lb-book3d__page--left::after,
.lb-book3d__page--right::after{ content: none; }

.lb-book3d[data-mode="single"] .lb-book3d__page--right{ display: none; }
.lb-book3d[data-mode="single"] .lb-book3d__page--left{
  border-radius: 18px;
  border: 1px solid rgba(0, 0, 0, 0.09);
  background: #fff;
  box-shadow:
    0 18px 40px rgba(0,0,0,0.16),
    0 6px 16px rgba(0,0,0,0.08);
}
.lb-book3d[data-mode="single"] .lb-book3d__page--left img{
  border-radius: 18px;
  background: #fff;
}

.lb-book3d[data-mode="single"] .lb-book3d__spread{
  filter: none;
}

/* ===== flip sheet ===== */
.lb-sheet{
  position: absolute;
  top: 0;
  bottom: 0;
  width: 50%;
  z-index: 12;
  transform-style: preserve-3d;
  -webkit-transform-style: preserve-3d;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;

  will-change: transform;
  transition: transform var(--sheetDur) cubic-bezier(0.18, 0.7, 0.12, 1);

  /* ✅ 넘기는 장은 좀 더 강조된 그림자 */
  box-shadow: 0 24px 80px rgba(0,0,0,0.18);

  /* ✅ 미세 z 분리 */
  transform: translateZ(calc(var(--zf) * 4)) rotateY(0deg);
}

.lb-sheet--single{ width: 100%; }

/* next: right -> left */
.lb-sheet--next{
  left: 50%;
  transform-origin: left center;
}
.lb-sheet--next.is-flipping{
  transform: translateZ(calc(var(--zf) * 4)) rotateY(-180deg);
}

/* prev: left -> right */
.lb-sheet--prev{
  left: 0;
  transform-origin: right center;
}
.lb-sheet--prev.is-flipping{
  transform: translateZ(calc(var(--zf) * 4)) rotateY(180deg);
}

.lb-book3d[data-mode="single"] .lb-sheet--next,
.lb-book3d[data-mode="single"] .lb-sheet--prev{
  left: 0;
}

.lb-book3d[data-mode="single"] .lb-sheet--single{
  transition:
    transform calc(var(--sheetDur) * 0.82) cubic-bezier(0.22, 0.7, 0.12, 1),
    opacity calc(var(--sheetDur) * 0.82) ease;
  box-shadow:
    0 20px 42px rgba(0,0,0,0.18),
    0 8px 20px rgba(0,0,0,0.10);
}

.lb-book3d[data-mode="single"] .lb-sheet--single.lb-sheet--next{
  transform-origin: 86% center;
}

.lb-book3d[data-mode="single"] .lb-sheet--single.lb-sheet--prev{
  transform-origin: 14% center;
}

.lb-book3d[data-mode="single"] .lb-sheet--single.lb-sheet--next.is-flipping{
  transform: translateZ(calc(var(--zf) * 4)) translateX(-22%) rotate(-7deg) scale(0.95);
  opacity: 0;
}

.lb-book3d[data-mode="single"] .lb-sheet--single.lb-sheet--prev.is-flipping{
  transform: translateZ(calc(var(--zf) * 4)) translateX(22%) rotate(7deg) scale(0.95);
  opacity: 0;
}

/* faces */
.lb-sheet__face{
  position: absolute;
  inset: 0;
  background: #ffffff;
  overflow: hidden;

  border: none;              /* ✅ border 제거 */
  border-radius: 0;          /* ✅ radius 제거 */

  display: grid;
  place-items: center;

  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform-style: preserve-3d;
  -webkit-transform-style: preserve-3d;

  /* ✅ face끼리 z-fighting 방지 */
  transform: translateZ(var(--zf));
}

.lb-sheet__face img{
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

/* ✅ back face는 정석 rotateY(180deg)만 (좌우 반전 깜빡임 방지) */
.lb-sheet__face--back{
  transform: rotateY(180deg) translateZ(var(--zf));
}

.lb-book3d[data-mode="single"] .lb-sheet__face{
  border-radius: 18px;
  border: 1px solid rgba(0,0,0,0.09);
  box-shadow: 0 14px 28px rgba(0,0,0,0.12);
}

.lb-book3d[data-mode="single"] .lb-sheet__face img{
  border-radius: 18px;
}

.lb-book3d[data-mode="single"] .lb-sheet__face--back{
  display: none;
}

/* shading during flip (미니멀) */
.lb-sheet__face::after{
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.0;
  transition: opacity var(--sheetDur) ease;
}

.lb-sheet--next .lb-sheet__face--front::after{
  opacity: 0.10;
  background: linear-gradient(to left, rgba(0,0,0,0.22), transparent 60%);
}
.lb-sheet--prev .lb-sheet__face--front::after{
  opacity: 0.10;
  background: linear-gradient(to right, rgba(0,0,0,0.22), transparent 60%);
}
.lb-sheet.is-flipping .lb-sheet__face::after{ opacity: 0.18; }

.lb-sheet__blank{ width: 100%; height: 100%; }

/* nav + hint */
.lb-viewer__nav{
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  pointer-events: none;
  z-index: 30;
}
.lb-viewer__hit{
  pointer-events: auto;
  cursor: pointer;
}

.lb-viewer__hint{
  position: absolute;
  bottom: 12px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 11px;
  color: var(--text);
  background: rgba(255,255,255,0.92);
  border: none;                 /* ✅ hint도 테두리 제거 (더 깔끔하게) */
  padding: 6px 10px;
  border-radius: 999px;
  box-shadow: 0 10px 22px rgba(0,0,0,0.10);
  z-index: 31;
}

/* chapter end popup */
.lb-chapter-end{
  position: absolute;
  inset: 0;
  z-index: 62;
  pointer-events: none;

  display: grid;
  place-items: center;

  background: rgba(255, 255, 255, 0.24);
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
}

.lb-chapter-end__panel{
  pointer-events: auto;
  min-width: 164px;
  padding: 14px 16px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.74);
  box-shadow: 0 14px 28px rgba(0,0,0,0.12);
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: center;
  gap: 14px;
}

.lb-chapter-end__replay{
  width: 54px;
  height: 54px;
  border-radius: 999px;
  border: 1px solid rgba(0,0,0,0.32);
  background: rgba(255,255,255,0.82);
  color: var(--text);
  cursor: pointer;
  display: grid;
  place-items: center;
}

.lb-chapter-end__replay-icon{
  font-size: 26px;
  line-height: 1;
}

.lb-chapter-end__contents{
  width: 54px;
  height: 54px;
  border-radius: 999px;
  border: 1px solid rgba(0,0,0,0.32);
  background: rgba(255,255,255,0.82);
  color: var(--text);
  cursor: pointer;
  display: grid;
  place-items: center;
}

.lb-chapter-end__contents-icon{
  display: block;
  width: 16px;
  height: 2px;
  background: rgba(0,0,0,0.76);
  box-shadow:
    0 -5px 0 rgba(0,0,0,0.76),
    0 5px 0 rgba(0,0,0,0.76);
}

.lb-chapter-end__replay:focus{ outline: none; }
.lb-chapter-end__contents:focus{ outline: none; }
.lb-chapter-end__replay:focus-visible,
.lb-chapter-end__contents:focus-visible{
  outline: 1px solid var(--border);
  outline-offset: 2px;
}

/* reduce motion */
@media (prefers-reduced-motion: reduce){
  :root{ --sheetDur: 1ms; }
  .lb-book3d__stack{ transition: none; }
}

/* =========================
   Responsive (section-specific)
   ========================= */
@media (max-width: 980px){
  .lb-a4--main{
    width: min(480px, calc(100% - 36px));
    max-width: calc(100% - 36px);
  }
}

@media (max-width: 760px){
  .lb-a4--main{
    width: min(420px, calc(100% - 36px));
    max-width: calc(100% - 36px);
  }

  .lb-book-shell{
    width: min(420px, 92vw);
    /*height: min(calc(100% - 24px), 78vh);*/
  }
}

/* =========================================================
   SECTION 2 REDESIGN (Magazines layout)
   - desktop/tablet: left cover + right meta/chapters
   - mobile: card-based flow (main -> info -> chapter cover)
   ========================================================= */
#sec-contents .lb-canvas{
  align-items: stretch;
  justify-content: stretch;
  background: #ffffff;
  overflow: hidden;
}

#sec-contents .lb-contents-grid{
  width: 100%;
  height: 100%;
  padding: clamp(18px, 2.2vw, 34px) 0;
  margin: 0;
  display: block;
  overflow: hidden;
  background: transparent;
  scrollbar-width: none;
}

#sec-contents .lb-contents-grid::-webkit-scrollbar{
  display: none;
}

.lb-s2-layout{
  width: 100%;
  max-width: none;
  height: 100%;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 0;
  align-items: center;
}

.lb-s2-left{
  min-width: 0;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding-right: clamp(10px, 1.6vw, 24px);
}

.lb-s2-right{
  min-width: 0;
  /* width: min(620px, calc(100% - 44px));
  max-width: min(620px, calc(100% - 44px)); */
  display: flex;
  flex-direction: column;
  gap: clamp(22px, 2.8vh, 42px);
  align-items: flex-start;
  justify-self: center;
}

.lb-s2-cover-btn{
  position: relative;
  width: min(100%, 560px);
  aspect-ratio: 210 / 297;
  border: 1px solid rgba(0, 0, 0, 0.06);
  border-radius: 0;
  padding: 0px;
  background: #ffffff;
  box-shadow:
    0 1px 0 rgba(255, 255, 255, 0.78) inset,
    0 14px 28px rgba(0, 0, 0, 0.08);
  overflow: hidden;
  cursor: pointer;
  transition: transform 260ms ease, box-shadow 260ms ease;
}

.lb-s2-cover-btn:focus{
  outline: none;
}

.lb-s2-cover-btn:focus-visible{
  outline: 1px solid rgba(0, 0, 0, 0.72);
  outline-offset: 2px;
}

.lb-s2-cover-img{
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center;
  display: block;
  transition: transform 300ms ease, opacity 300ms ease, filter 300ms ease;
}

.lb-s2-cover-overlay{
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.68);
  opacity: 0;
  transition: opacity 280ms ease;
  pointer-events: auto;
}

.lb-s2-cover-overlay__text{
  font-size: clamp(12px, 1vw, 16px);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: none;
  color: rgba(0, 0, 0, 0.92);
}

.lb-s2-cover-overlay__panel{
  width: min(84%, 420px);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.lb-s2-cover-overlay__chapters{
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.lb-s2-cover-overlay__chapters .lb-s2-chapter-list{
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 20px;
  justify-items: center;
}

.lb-s2-cover-overlay__chapters .lb-s2-chapter-btn{
  display: block;
  padding: 0;
  cursor: pointer;
  font-size: clamp(10px, 0.76vw, 12px);
  line-height: 1.32;
  text-align: center;
  color: rgba(0, 0, 0, 0.82);
}

.lb-s2-cover-overlay__back{
  display: none;
  padding: 3px 10px;
  font-size: clamp(11px, 0.84vw, 13px);
  line-height: 1.2;
  letter-spacing: 0.08em;
  color: rgba(0, 0, 0, 0.9);
  border: none;
  cursor: pointer;
  user-select: none;
}

.lb-s2-cover-btn:hover{
  transform: translateY(-2px);
  box-shadow:
    0 1px 0 rgba(255, 255, 255, 0.72) inset,
    0 20px 32px rgba(0, 0, 0, 0.11);
}

.lb-s2-cover-btn.is-chapter-selected:hover .lb-s2-cover-img{
  transform: translateY(-12px);
  opacity: 0.42;
  filter: saturate(0.9);
}

.lb-s2-cover-btn.is-main-cover:hover .lb-s2-cover-img{
  transform: translateY(-8px);
  opacity: 0.56;
  filter: saturate(0.94);
}

.lb-s2-mobile-cover-btn.is-main-cover:hover .lb-s2-cover-img,
.lb-s2-mobile-cover-btn.is-chapter-selected:hover .lb-s2-cover-img{
  transform: none;
  opacity: 1;
  filter: none;
}

.lb-s2-cover-btn:hover .lb-s2-cover-overlay,
.lb-s2-cover-btn.is-select-needed .lb-s2-cover-overlay,
.lb-s2-cover-btn.is-click-cover-hint .lb-s2-cover-overlay{
  opacity: 1;
}

.lb-s2-mobile-cover-btn:hover:not(.is-select-needed):not(.is-click-cover-hint) .lb-s2-cover-overlay{
  opacity: 0;
}

.lb-s2-cover-btn.is-select-needed .lb-s2-cover-overlay__text{
  animation: lb-s2-select-bounce 300ms ease-in-out 3;
}

.lb-s2-cover-btn.is-click-cover-hint .lb-s2-cover-img{
  transform: translateY(8px);
  opacity: 0.04;
  filter: blur(1px);
}

.lb-s2-cover-btn.is-click-cover-hint .lb-s2-cover-overlay__panel{
  gap: 26px;
}

.lb-s2-cover-btn.is-click-cover-hint .lb-s2-cover-overlay__chapters .lb-s2-chapter-list{
  display: none;
}

.lb-s2-cover-btn.is-click-cover-hint .lb-s2-cover-overlay__back{
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.lb-s2-cover-btn.is-click-cover-hint .lb-s2-cover-overlay__text{
  animation: lb-s2-click-cover-pulse 780ms ease-in-out 1;
}

@keyframes lb-s2-select-bounce{
  0%{ transform: translateY(0); }
  50%{ transform: translateY(-5px); }
  100%{ transform: translateY(0); }
}

@keyframes lb-s2-click-cover-pulse{
  0%{ opacity: 0.52; transform: translateY(0); }
  50%{ opacity: 1; transform: translateY(-2px); }
  100%{ opacity: 0.52; transform: translateY(0); }
}

.lb-s2-meta{
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: clamp(10px, 1.4vh, 18px);
}

.lb-s2-title{
  margin: 0;
  padding: 0;
  font-size: clamp(17px, 1.65vw, 24px);
  font-weight: 500;
  letter-spacing: 0.12em;
  color: rgba(0, 0, 0, 0.93);
  line-height: 1.2;
  text-transform: none;
}

.lb-s2-title__season,
.lb-s2-title__label{
  font-weight: 500;
}

.lb-s2-subtitle{
  font-size: clamp(11px, 0.88vw, 13px);
  letter-spacing: 0.14em;
  color: rgba(0, 0, 0, 0.88);
  line-height: 1.2;
  text-transform: none;
}

.lb-s2-desc{
  margin: 0;
  max-width: 44ch;
  font-size: clamp(11px, 0.8vw, 13px);
  line-height: 1.45;
  letter-spacing: 0.01em;
  color: rgba(0, 0, 0, 0.78);
  white-space: pre-line;
}

.lb-s2-desc.is-empty{
  display: none;
}

.lb-s2-chapters{
  width: 100%;
  overflow: visible;
  margin: 40px 0 40px 0;
}

.lb-s2-chapter-list{
  width: 100%;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(8px, 1.1vh, 13px) clamp(16px, 2.2vw, 34px);
  align-items: start;
  overflow: visible;
}

.lb-s2-chapter-empty{
  grid-column: 1 / -1;
  font-size: 12px;
  color: rgba(0, 0, 0, 0.48);
}

.lb-s2-chapter-btn{
  appearance: none;
  border: none;
  background: transparent;
  padding: 0;
  margin: 0;
  text-align: left;
  font-size: clamp(11px, 0.82vw, 13px);
  line-height: 1.4;
  letter-spacing: 0.03em;
  color: rgba(0, 0, 0, 0.68);
  cursor: pointer;
  transition: color 200ms ease, transform 200ms ease, opacity 200ms ease;
}

.lb-s2-chapter-btn:hover{
  color: rgba(0, 0, 0, 0.96);
  transform: translateY(-1px);
}

.lb-s2-chapter-btn:focus{
  outline: none;
}

.lb-s2-chapter-btn:focus-visible{
  outline: 1px solid rgba(0, 0, 0, 0.55);
  outline-offset: 2px;
}

.lb-s2-chapter-btn.is-active{
  color: rgba(0, 0, 0, 1);
  font-weight: 600;
}

.lb-s2-mobile-layout{
  width: min(520px, calc(100% - 36px));
  height: 100%;
  margin: 0 auto;
  display: grid;
  grid-template-rows: minmax(0, 43fr) minmax(0, 57fr);
  gap: 30px;
  --lb-s2-mobile-scale: 1;
}

.lb-s2-mobile-top{
  min-height: 0;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.lb-s2-mobile-cover-btn{
  width: auto;
  height: 100%;
  max-width: min(100%, 340px);
  aspect-ratio: 210 / 297;
  padding: clamp(8px, 2vw, 12px);
}

.lb-s2-mobile-bottom{
  min-height: 0;
  display: flex;
  flex-direction: column;
  gap: calc(16px * var(--lb-s2-mobile-scale));
  padding: 0 2px 2px;
  overflow: hidden;
}

.lb-s2-mobile-bottom .lb-s2-meta{
  width: 100%;
  align-items: flex-start;
  text-align: left;
  gap: calc(11px * var(--lb-s2-mobile-scale));
}

.lb-s2-mobile-bottom .lb-s2-title{
  font-size: calc(16px * var(--lb-s2-mobile-scale));
}

.lb-s2-mobile-bottom .lb-s2-subtitle{
  font-size: calc(11px * var(--lb-s2-mobile-scale));
  letter-spacing: calc(0.14em * var(--lb-s2-mobile-scale));
  line-height: 1.35;
}

.lb-s2-mobile-bottom .lb-s2-desc{
  font-size: calc(11.2px * var(--lb-s2-mobile-scale));
  line-height: 1.5;
  letter-spacing: 0.005em;
}

.lb-s2-mobile-bottom .lb-s2-desc + .lb-s2-desc{
  margin-top: calc(4px * var(--lb-s2-mobile-scale));
}

.lb-s2-mobile-bottom .lb-s2-chapters{
  flex: 1 1 auto;
  min-height: 0;
  margin-top: calc(40px * var(--lb-s2-mobile-scale));
  margin-bottom: calc(40px * var(--lb-s2-mobile-scale));
  overflow: hidden;
}

.lb-s2-mobile-bottom .lb-s2-chapter-list{
  height: 100%;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: calc(12px * var(--lb-s2-mobile-scale)) calc(18px * var(--lb-s2-mobile-scale));
  justify-items: center;
  align-content: start;
}

.lb-s2-mobile-bottom .lb-s2-chapter-btn{
  width: max-content;
  max-width: 100%;
  font-size: calc(10.8px * var(--lb-s2-mobile-scale));
  letter-spacing: calc(0.03em * var(--lb-s2-mobile-scale));
  line-height: 1.4;
  text-align: center;
}

@media (max-width: 1199px){
  #sec-contents .lb-canvas{
    background: #ffffff;
  }

  #sec-contents .lb-contents-grid{
    padding: clamp(16px, 3.4vw, 28px) 0;
  }

  .lb-s2-layout{
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 0;
  }

  .lb-s2-right{
    /* width: min(560px, calc(100% - 32px));
    max-width: min(560px, calc(100% - 32px)); */
    gap: clamp(18px, 2.2vh, 30px);
  }

  .lb-s2-chapter-list{
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 760px){
  #sec-contents .lb-canvas{
    background: #ffffff;
    display: grid;
    place-items: center;
  }

  #sec-contents .lb-contents-grid{
    padding: 10px 0;
  }

  .lb-s2-mobile-layout{
    width: min(520px, calc(100% - 36px));
    height: 100%;
    grid-template-rows: minmax(0, 42fr) minmax(0, 58fr);
    gap: 30px;
  }

  .lb-s2-mobile-cover-btn{
    max-width: min(100%, 320px);
    padding: 0px;
  }

  .lb-s2-mobile-bottom .lb-s2-title{
    font-size: calc(15px * var(--lb-s2-mobile-scale));
  }

  .lb-s2-mobile-bottom .lb-s2-subtitle{
    font-size: calc(10.6px * var(--lb-s2-mobile-scale));
  }

  .lb-s2-mobile-bottom .lb-s2-desc{
    font-size: calc(10.6px * var(--lb-s2-mobile-scale));
    line-height: 1.48;
    max-width: 100%;
  }

  .lb-s2-mobile-bottom .lb-s2-chapter-btn{
    font-size: calc(10.5px * var(--lb-s2-mobile-scale));
  }
}