/**
 * L13 Page 03 · 时间锚点（对齐 Page 02 全屏 + grid 左图右文）
 */

/* 左图右文：保持 lesson-screen 的 grid，避免被 shell 压成单列 flex */
#l13-book .panel.panel-split {
  display: grid !important;
  grid-template-columns: 1fr;
  gap: 0.65rem;
  align-items: stretch;
  min-height: 0;
  overflow: hidden;
}
@media (min-width: 640px) {
  #l13-book .panel.panel-split {
    grid-template-columns: minmax(220px, 48%) 1fr;
    gap: 0.85rem;
  }
}

#l13-book .panel.panel-split .stage-visual {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
}

#l13-book .panel.panel-split .stage-body {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  min-width: 0;
  min-height: 0;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

#l13-book .scene-frame--intro,
#l13-book .scene-frame--split {
  flex: 1 1 auto;
  width: 100%;
  aspect-ratio: 4 / 3;
  min-height: clamp(200px, 36vh, 460px);
  max-height: min(64vh, 520px) !important;
  height: auto !important;
  background: linear-gradient(145deg, #fffbeb, #fef3c7);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

#l13-book .scene-frame--intro img,
#l13-book .scene-frame--split img {
  display: block;
  width: 100%;
  height: 100%;
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  object-position: center center;
}

#l13-book .tier-label {
  background: var(--amber-bg, #fef3c7);
  color: var(--amber-ink, #92400e);
}
#l13-book .tier-label.tier-c {
  background: #fef3c7;
  color: #92400e;
}

#l13-book .panel-lead {
  font-weight: 800;
  margin: 0 0 0.35rem;
  line-height: 1.45;
  flex-shrink: 0;
}

#l13-book .hl-marker {
  background: var(--amber-bg, #fef3c7);
  color: var(--amber-ink, #92400e);
  padding: 0 0.12rem;
  border-radius: 4px;
  font-weight: 900;
}

#l13-book .btn.amber {
  background: linear-gradient(135deg, #fbbf24, #d97706);
  color: #fff;
  border-color: #b45309;
  box-shadow: 0 3px 0 rgba(180, 83, 9, 0.3);
}

/* 各屏：面板纵向填满，底栏按钮不滚走 */
#l13-book .lesson-page.active > .panel:not(.panel-split) {
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

#l13-book .lesson-page.active > .panel.panel-split {
  flex: 1 1 auto;
  min-height: 0;
}

#l13-book .lesson-page .btn-row {
  flex-shrink: 0;
  margin-top: auto;
  padding-top: 0.35rem;
}

/* 屏 1 · 配图全屏 */
#l13-book .panel-intro-markers {
  display: flex;
  flex-direction: column;
  min-height: 0;
  flex: 1 1 auto;
  padding: clamp(0.5rem, 1vw, 0.75rem);
}
#l13-book .panel-intro-markers .scene-frame--intro {
  flex: 1 1 auto;
  width: 100%;
  max-height: min(72vh, 560px);
}

/* 屏 1 · 时间锚点总览（保留供其它屏复用） */
#l13-book .lesson-page[data-page="1"] .marker-banner {
  text-align: center;
  padding: 0.85rem 0.75rem;
  margin: 0;
  border-radius: 16px;
  border: 4px solid var(--amber, #d97706);
  background: linear-gradient(135deg, #fffbeb, #fef3c7);
  flex-shrink: 0;
}
#l13-book .marker-banner .big {
  font-size: clamp(1.15rem, 2.4vw + 0.5rem, 1.65rem);
  font-weight: 900;
  color: #92400e;
  line-height: 1.35;
}
#l13-book .marker-banner .sub {
  font-size: 0.86rem;
  font-weight: 700;
  color: #5d4037;
  margin-top: 0.35rem;
  line-height: 1.45;
}

/* 屏 2 · 锚点导图 */
#l13-book .panel-anchor {
  display: flex;
  flex-direction: column;
  min-height: 0;
}
#l13-book .anchor-map {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  justify-content: center;
  margin: 0.35rem 0;
  flex-shrink: 0;
}
#l13-book .anchor-chip {
  padding: 0.5rem 0.85rem;
  border-radius: 12px;
  border: 2px solid var(--edge, #5d4037);
  background: #fff;
  font-weight: 900;
  font-size: clamp(0.82rem, 0.95vw + 0.45rem, 0.98rem);
  cursor: pointer;
  font-family: inherit;
  touch-action: manipulation;
  transition: transform 0.15s, background 0.15s;
}
#l13-book .anchor-chip.active {
  background: var(--amber-bg, #fef3c7);
  border-color: var(--amber, #d97706);
  color: var(--amber-ink, #92400e);
  transform: scale(1.04);
}
#l13-book .anchor-detail {
  margin-top: 0.35rem;
  padding: 0.75rem;
  border-radius: 14px;
  border: 3px solid #fcd34d;
  background: #fffbeb;
  flex: 1 1 auto;
  min-height: 120px;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}
#l13-book .anchor-ex-pos {
  text-align: center;
  font-weight: 800;
  font-size: 0.82rem;
  color: #64748b;
  margin: 0 0 0.25rem;
  flex-shrink: 0;
}
#l13-book .anchor-rule-hint {
  font-size: 0.82rem;
  font-weight: 800;
  color: #92400e;
  margin: 0 0 0.4rem;
  line-height: 1.45;
  flex-shrink: 0;
}
#l13-book .anchor-reveal-slot {
  margin-top: 0.25rem;
  padding: 0.7rem;
  border-radius: 14px;
  border: 2px dashed #cbd5e1;
  background: #f8fafc;
  flex: 1 1 auto;
  min-height: 140px;
}
#l13-book .anchor-reveal-slot.is-covered {
  cursor: pointer;
}
#l13-book .anchor-reveal-slot.is-covered .anchor-ex-body {
  visibility: hidden;
  height: 0;
  overflow: hidden;
  margin: 0;
  opacity: 0;
}
#l13-book .anchor-reveal-slot.is-revealed {
  border-style: solid;
  border-color: #94a3b8;
  cursor: default;
}
#l13-book .anchor-reveal-slot.is-revealed .anchor-tap-hint {
  display: none;
}
#l13-book .anchor-ex-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: center;
}
#l13-book .anchor-tap-hint {
  font-size: 0.78rem;
  font-weight: 800;
  color: #64748b;
  padding: 0.3rem 0.55rem;
  border-radius: 8px;
  background: #e2e8f0;
  border: none;
  cursor: pointer;
  font-family: inherit;
}
#l13-book .btn-speak-chip {
  min-height: 40px;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  border: 2px solid var(--edge, #5d4037);
  background: #fff;
  font-weight: 800;
  font-size: 0.82rem;
  cursor: pointer;
  touch-action: manipulation;
  font-family: inherit;
}
#l13-book .btn-speak-chip:hover {
  background: #fffbeb;
}
#l13-book .anchor-scenario {
  font-size: 0.9rem;
  font-weight: 800;
  color: #475569;
  margin: 0 0 0.35rem;
  line-height: 1.45;
}
#l13-book .anchor-use {
  font-size: 0.78rem;
  font-weight: 700;
  color: #0f766e;
  margin-top: 0.35rem;
  line-height: 1.4;
  padding: 0.35rem 0.5rem;
  border-radius: 8px;
  background: #f0fdfa;
}
#l13-book .btn.violet {
  background: linear-gradient(135deg, #a78bfa, #7c3aed);
  color: #fff;
  border-color: #5b21b6;
  box-shadow: 0 3px 0 rgba(91, 33, 182, 0.28);
}

/* 屏 3–6 · 左栏双图轮播（by / before / when / already） */
#l13-book .panel.panel-dual-carousel {
  align-items: stretch;
  min-height: 0;
}

#l13-book .lesson-page[data-page="3"].active > .panel.panel-dual-carousel,
#l13-book .lesson-page[data-page="4"].active > .panel.panel-dual-carousel,
#l13-book .lesson-page[data-page="5"].active > .panel.panel-dual-carousel,
#l13-book .lesson-page[data-page="6"].active > .panel.panel-dual-carousel {
  overflow: hidden;
}

#l13-book .panel-dual-carousel .stage-visual {
  flex: 1 1 auto;
  min-height: clamp(200px, 38vh, 480px);
  max-height: min(64vh, 520px);
  width: 100%;
  display: flex;
  flex-direction: column;
  align-self: stretch;
  overflow: hidden;
}

#l13-book #by-visual,
#l13-book #before-visual,
#l13-book #when-visual,
#l13-book #already-visual,
#l13-book .dual-visual-stack,
#l13-book .by-visual-stack {
  display: flex;
  flex-direction: column;
  gap: clamp(0.2rem, 0.4vh, 0.35rem);
  flex: 1 1 auto;
  min-height: 0;
  height: 100%;
  width: 100%;
}

#l13-book .dual-fig,
#l13-book .by-fig {
  margin: 0;
  flex: 1 1 0;
  min-height: 0;
  display: flex;
  flex-direction: column;
  border-radius: 12px;
  overflow: hidden;
  border: 3px solid var(--edge, #5d4037);
  background: linear-gradient(145deg, #fffbeb, #fef3c7);
}

#l13-book .dual-fig img,
#l13-book .by-fig img {
  display: block;
  width: 100%;
  height: 100%;
  flex: 1 1 auto;
  min-height: 0;
  max-width: 100%;
  max-height: none !important;
  object-fit: contain;
  object-position: center center;
  background: #fff;
}
#l13-book .dual-fig figcaption,
#l13-book .by-fig figcaption {
  flex-shrink: 0;
  font-size: 0.72rem;
  font-weight: 900;
  text-align: center;
  padding: 0.3rem 0.45rem;
  background: #fef3c7;
  color: #92400e;
  line-height: 1.35;
}
#l13-book .dual-fig-a figcaption,
#l13-book .by-fig-a figcaption {
  background: #ede9fe;
  color: #5b21b6;
}
#l13-book .dual-fig-b figcaption,
#l13-book .by-fig-b figcaption {
  background: #dbeafe;
  color: #1d4ed8;
}

#l13-book .panel-dual-carousel .carousel-card {
  padding: 0.85rem;
  border-radius: 14px;
  border: 3px solid #fcd34d;
  background: linear-gradient(180deg, #fff, #fffbeb);
  flex: 1 1 auto;
  min-height: 100px;
  flex-shrink: 0;
}
#l13-book .tag-pill {
  font-size: 0.72rem;
  font-weight: 900;
  padding: 0.12rem 0.5rem;
  border-radius: 999px;
  background: var(--amber-bg, #fef3c7);
  color: var(--amber-ink, #92400e);
  display: inline-block;
  margin-bottom: 0.35rem;
}
#l13-book .carousel-dots {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  justify-content: center;
  margin-top: 0.45rem;
  flex-shrink: 0;
}
#l13-book .carousel-dots button {
  width: 2.1rem;
  height: 2.1rem;
  border-radius: 999px;
  border: 2px solid var(--edge, #5d4037);
  background: #fff;
  font-weight: 900;
  font-size: 0.82rem;
  cursor: pointer;
  font-family: inherit;
  touch-action: manipulation;
}
#l13-book .carousel-dots button.active {
  background: var(--amber, #d97706);
  color: #fff;
  border-color: #b45309;
}

/* 屏 4–6 · 例句列表 */
#l13-book .panel-examples {
  display: flex;
  flex-direction: column;
  min-height: 0;
}
#l13-book .example-list {
  flex: 1 1 auto;
  min-height: 0;
  overflow-y: auto;
  max-height: min(52vh, 460px);
  padding-right: 0.1rem;
}
#l13-book .example-list .ex-item {
  margin: 0.5rem 0;
  padding: 0.6rem 0.7rem;
  border-radius: 12px;
  border: 2px solid #fde68a;
  background: #fff;
}
#l13-book .ex-item .btn-speak-mini {
  margin-top: 0.35rem;
  min-height: 40px;
  padding: 0.35rem 0.7rem;
  font-size: 0.8rem;
  border-radius: 999px;
  border: 2px solid var(--edge, #5d4037);
  background: #fff;
  font-weight: 800;
  cursor: pointer;
  font-family: inherit;
  touch-action: manipulation;
}

#l13-book .panel-when .stage-body .example-list {
  flex: 1 1 auto;
  max-height: none;
}

/* 屏 7 · 配对（铺满屏高，无滚动条） */
#l13-book .lesson-page[data-page="7"] {
  gap: 0.35rem;
}

#l13-book .lesson-page[data-page="7"] .page-head {
  padding-bottom: 0.2rem;
}

#l13-book .lesson-page[data-page="7"].active > .panel.panel-match {
  overflow: hidden;
}

#l13-book .lesson-page[data-page="7"] .panel-lead {
  margin: 0 0 0.25rem;
  font-size: clamp(0.78rem, 1.4vh, 0.88rem);
  line-height: 1.35;
}

#l13-book .panel-match {
  display: flex;
  flex-direction: column;
  min-height: 0;
  flex: 1 1 auto;
  overflow: hidden;
  gap: 0.25rem;
}

#l13-book .match-zone {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(0.4rem, 1.2vw, 0.75rem);
  margin: 0;
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
  align-items: stretch;
}

#l13-book .match-col {
  display: flex;
  flex-direction: column;
  min-height: 0;
  min-width: 0;
}

#l13-book .match-col h4 {
  margin: 0 0 0.2rem;
  font-size: clamp(0.72rem, 1.2vh, 0.82rem);
  color: #64748b;
  flex-shrink: 0;
  line-height: 1.2;
}

#l13-book .match-pool {
  display: grid;
  grid-template-rows: repeat(6, minmax(0, 1fr));
  gap: clamp(0.2rem, 0.65vh, 0.4rem);
  flex: 1 1 auto;
  min-height: 0;
}

#l13-book .match-chip {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  min-height: 0;
  height: 100%;
  padding: clamp(0.28rem, 0.9vh, 0.5rem) clamp(0.35rem, 1vw, 0.6rem);
  border-radius: 10px;
  border: 2px solid #cbd5e1;
  background: #fff;
  font-weight: 800;
  font-size: clamp(0.72rem, 1.05vh + 0.32rem, 0.9rem);
  cursor: pointer;
  text-align: left;
  line-height: 1.3;
  font-family: inherit;
  touch-action: manipulation;
  overflow: hidden;
}

#l13-book .match-chip .match-chip-zh {
  font-size: clamp(0.65rem, 0.85vh + 0.22rem, 0.76rem);
  color: #64748b;
  font-weight: 700;
  line-height: 1.25;
  margin-top: 0.12rem;
}

/* 屏 7 · 右侧句子：方框内横向（英 + 中并排） */
#l13-book #match-right .match-chip {
  flex-direction: row;
  align-items: center;
  justify-content: flex-start;
  gap: clamp(0.3rem, 0.8vw, 0.55rem);
  flex-wrap: wrap;
  text-align: left;
}

#l13-book #match-right .match-chip .match-chip-en {
  flex: 1 1 auto;
  min-width: 0;
  line-height: 1.28;
}

#l13-book #match-right .match-chip .match-chip-zh {
  flex: 0 0 auto;
  max-width: 46%;
  margin-top: 0;
  padding-left: clamp(0.3rem, 0.7vw, 0.45rem);
  border-left: 2px solid #e2e8f0;
  line-height: 1.28;
  white-space: nowrap;
}
#l13-book .match-chip.selected {
  outline: 3px solid var(--amber, #d97706);
  border-color: var(--amber, #d97706);
}
#l13-book .match-chip.matched {
  opacity: 0.45;
  pointer-events: none;
  background: var(--ok-bg, #ecfdf5);
  border-color: var(--ok, #047857);
}
#l13-book .match-chip.bad {
  animation: l13-p03-shake 0.4s;
  background: var(--bad-bg, #fef2f2);
}
@keyframes l13-p03-shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-4px); }
  75% { transform: translateX(4px); }
}
#l13-book #match-fb {
  flex-shrink: 0;
  min-height: 1.35em;
  margin: 0;
  line-height: 1.35;
}

#l13-book .lesson-page[data-page="7"] .btn-row {
  padding-top: 0.2rem;
}

/* 屏 8 · 填空（铺满屏高，无滚动条） */
#l13-book .lesson-page[data-page="8"] {
  gap: 0.35rem;
}

#l13-book .lesson-page[data-page="8"] .page-head {
  padding-bottom: 0.2rem;
}

#l13-book .lesson-page[data-page="8"].active > .panel.panel-fill {
  overflow: hidden;
}

#l13-book .lesson-page[data-page="8"] .panel-lead {
  margin: 0 0 0.25rem;
  font-size: clamp(0.78rem, 1.4vh, 0.88rem);
  line-height: 1.35;
  flex-shrink: 0;
}

#l13-book .panel-fill {
  display: flex;
  flex-direction: column;
  min-height: 0;
  flex: 1 1 auto;
  overflow: hidden;
  gap: 0.2rem;
}

#l13-book .fill-slot,
#l13-book #fill-box {
  display: flex;
  flex: 1 1 auto;
  align-items: center;
  justify-content: center;
  min-height: 0;
  overflow: hidden;
  margin: 0;
  padding: 0;
}

#l13-book .lesson-page[data-page="8"] .fill-item {
  width: 100%;
  max-width: 52rem;
  flex: 1 1 auto;
  min-height: min(100%, 100%);
  padding: clamp(0.45rem, 1.8vh, 1rem) clamp(0.5rem, 2vw, 1.1rem);
  justify-content: center;
}

#l13-book .fill-item {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
  margin: 0;
  padding: clamp(0.22rem, 0.75vh, 0.42rem) clamp(0.35rem, 1vw, 0.55rem);
  border-radius: 10px;
  border: 2px solid #e2e8f0;
  background: #fff;
  overflow: hidden;
}

#l13-book .lesson-page[data-page="8"] .fill-stem {
  font-size: clamp(0.88rem, 1.65vh + 0.38rem, 1.15rem);
  margin-bottom: clamp(0.3rem, 1.1vh, 0.65rem);
  text-align: center;
}

#l13-book .lesson-page[data-page="8"] .fill-opts {
  justify-content: center;
  max-width: 40rem;
  margin: 0 auto;
  width: 100%;
}

#l13-book .lesson-page[data-page="8"] .fill-opts button {
  min-height: clamp(38px, 5.5vh, 50px);
  font-size: clamp(0.78rem, 1.2vh + 0.32rem, 0.95rem);
}

#l13-book .lesson-page[data-page="8"] .fill-item .fb {
  text-align: center;
  font-size: clamp(0.72rem, 1vh + 0.28rem, 0.86rem);
  margin-top: clamp(0.2rem, 0.8vh, 0.45rem);
}

#l13-book .fill-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.35rem;
  flex-shrink: 0;
}

#l13-book .fill-progress {
  font-weight: 900;
  font-size: clamp(0.78rem, 1.1vh + 0.32rem, 0.92rem);
  color: var(--amber-ink, #92400e);
}

#l13-book .fill-dots {
  flex: 1 1 auto;
  justify-content: flex-end;
  margin-top: 0;
  max-height: 4.5rem;
  overflow: hidden;
}

#l13-book .fill-dots button {
  width: 1.65rem;
  height: 1.65rem;
  font-size: 0.62rem;
}

#l13-book .fill-dots button.done {
  background: var(--ok-bg, #ecfdf5);
  border-color: var(--ok, #047857);
  color: var(--ok, #047857);
}

#l13-book .lesson-page[data-page="8"] .btn-row {
  padding-top: 0.2rem;
  flex-shrink: 0;
}

#l13-book .fill-item.done {
  border-color: var(--ok, #047857);
  background: var(--ok-bg, #ecfdf5);
}

#l13-book .fill-stem {
  font-weight: 800;
  margin: 0 0 clamp(0.12rem, 0.35vh, 0.22rem);
  line-height: 1.32;
  font-size: clamp(0.72rem, 1.05vh + 0.32rem, 0.88rem);
  flex-shrink: 0;
}

#l13-book .fill-blank {
  display: inline-block;
  min-width: 3.5rem;
  border-bottom: 2px dashed var(--amber, #d97706);
  padding: 0 0.15rem;
}

#l13-book .fill-opts {
  display: flex;
  flex-wrap: nowrap;
  gap: clamp(0.18rem, 0.45vh, 0.32rem);
  flex-shrink: 0;
}

#l13-book .fill-opts button {
  flex: 1 1 0;
  min-width: 0;
  min-height: clamp(30px, 4.2vh, 40px);
  padding: clamp(0.2rem, 0.5vh, 0.35rem) clamp(0.25rem, 0.6vw, 0.5rem);
  border-radius: 999px;
  border: 2px solid #cbd5e1;
  background: #fff;
  font-weight: 800;
  font-size: clamp(0.68rem, 0.95vh + 0.28rem, 0.8rem);
  line-height: 1.25;
  cursor: pointer;
  font-family: inherit;
  touch-action: manipulation;
  white-space: normal;
  text-align: center;
  word-break: break-word;
}

#l13-book .fill-item .fb {
  flex-shrink: 0;
  margin: clamp(0.08rem, 0.25vh, 0.15rem) 0 0;
  padding: 0;
  font-size: clamp(0.62rem, 0.85vh + 0.2rem, 0.72rem);
  line-height: 1.25;
  min-height: 0;
}

#l13-book .fill-item .fb:empty {
  display: none;
}

#l13-book .fill-opts button.ok {
  background: var(--ok-bg, #ecfdf5);
  border-color: var(--ok, #047857);
}

#l13-book .fill-opts button.bad {
  background: var(--bad-bg, #fef2f2);
  border-color: var(--bad, #b91c1c);
}

/* 屏 9 · 快选（每题一屏 + 6 秒倒计时 + 对错动画） */
#l13-book .lesson-page[data-page="9"] {
  gap: 0.35rem;
}

#l13-book .lesson-page[data-page="9"] .page-head {
  padding-bottom: 0.2rem;
}

#l13-book .lesson-page[data-page="9"].active > .panel.panel-quick-quiz {
  overflow: hidden;
}

#l13-book .lesson-page[data-page="9"] .panel-lead {
  margin: 0 0 0.25rem;
  font-size: clamp(0.78rem, 1.4vh, 0.88rem);
  line-height: 1.35;
  flex-shrink: 0;
}

#l13-book .panel-quick-quiz {
  display: flex;
  flex-direction: column;
  min-height: 0;
  flex: 1 1 auto;
  overflow: hidden;
  gap: 0.25rem;
}

#l13-book .quiz-timer-bar {
  position: relative;
  flex-shrink: 0;
  height: clamp(28px, 4.5vh, 38px);
  border-radius: 999px;
  background: #e2e8f0;
  overflow: hidden;
  border: 2px solid #cbd5e1;
}

#l13-book .quiz-timer-fill {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 100%;
  transform: scaleX(1);
  transform-origin: left center;
  background: linear-gradient(90deg, #0d9488, #2dd4bf);
  will-change: transform;
}

#l13-book .quiz-timer-bar.is-urgent .quiz-timer-fill {
  background: linear-gradient(90deg, #d97706, #fbbf24);
}

#l13-book .quiz-timer-bar.is-timeout .quiz-timer-fill {
  background: linear-gradient(90deg, #b91c1c, #ef4444);
}

#l13-book .quiz-timer-text {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  font-weight: 900;
  font-size: clamp(0.9rem, 1.5vh + 0.35rem, 1.1rem);
  color: #0f172a;
  text-shadow: 0 0 8px rgba(255, 255, 255, 0.85);
}

#l13-book .quick-quiz-stage {
  position: relative;
  display: flex;
  flex: 1 1 auto;
  align-items: center;
  justify-content: center;
  min-height: 0;
  overflow: hidden;
}

#l13-book #quick-quiz {
  display: flex;
  width: 100%;
  max-width: 52rem;
  margin: 0 auto;
  min-height: 0;
  flex: 1 1 auto;
  align-items: center;
  justify-content: center;
}

#l13-book .lesson-page[data-page="9"] .quiz-item {
  display: flex;
  flex-direction: column;
  justify-content: center;
  width: 100%;
  min-height: 0;
  margin: 0;
  padding: clamp(0.45rem, 1.8vh, 1rem) clamp(0.5rem, 2vw, 1.1rem);
  border-radius: 12px;
  border: 2px solid #e2e8f0;
  background: #fff;
  overflow: hidden;
}

#l13-book .lesson-page[data-page="9"] .quiz-item.done {
  border-color: var(--ok, #047857);
  background: var(--ok-bg, #ecfdf5);
}

#l13-book .lesson-page[data-page="9"] .quiz-stem {
  font-weight: 800;
  margin: 0 0 clamp(0.3rem, 1.1vh, 0.65rem);
  line-height: 1.38;
  font-size: clamp(0.88rem, 1.65vh + 0.38rem, 1.15rem);
  flex-shrink: 0;
  text-align: center;
}

#l13-book .lesson-page[data-page="9"] .opt-row {
  display: flex;
  flex-direction: column;
  gap: clamp(0.28rem, 0.85vh, 0.5rem);
  margin-top: 0;
  flex-shrink: 0;
  width: 100%;
  max-width: 36rem;
  margin-left: auto;
  margin-right: auto;
}

#l13-book .lesson-page[data-page="9"] .opt-row button {
  flex: 0 0 auto;
  width: 100%;
  min-height: clamp(38px, 5.5vh, 50px);
  padding: clamp(0.28rem, 0.65vh, 0.45rem) clamp(0.45rem, 1vw, 0.7rem);
  border-radius: 999px;
  border: 2px solid #cbd5e1;
  background: #fff;
  font-weight: 800;
  font-size: clamp(0.78rem, 1.2vh + 0.32rem, 0.95rem);
  line-height: 1.28;
  text-align: center;
  white-space: normal;
  word-break: break-word;
  cursor: pointer;
  font-family: inherit;
  touch-action: manipulation;
}

#l13-book .lesson-page[data-page="9"] .opt-row button:disabled {
  cursor: default;
}

#l13-book .lesson-page[data-page="9"] .opt-row button.ok {
  background: var(--ok-bg, #ecfdf5);
  border-color: var(--ok, #047857);
}

#l13-book .lesson-page[data-page="9"] .opt-row button.bad {
  background: var(--bad-bg, #fef2f2);
  border-color: var(--bad, #b91c1c);
}

#l13-book .lesson-page[data-page="9"] .quiz-item.quiz-result-ok {
  animation: l13-quiz-card-ok 0.55s ease;
}

#l13-book .lesson-page[data-page="9"] .quiz-item.quiz-result-bad {
  animation: l13-quiz-card-bad 0.5s ease;
  border-color: var(--bad, #b91c1c);
}

@keyframes l13-quiz-card-ok {
  0% { box-shadow: 0 0 0 0 rgba(4, 120, 87, 0.45); }
  45% { box-shadow: 0 0 0 12px rgba(4, 120, 87, 0); transform: scale(1.01); }
  100% { box-shadow: none; transform: none; }
}

@keyframes l13-quiz-card-bad {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-6px); }
  40% { transform: translateX(6px); }
  60% { transform: translateX(-5px); }
  80% { transform: translateX(5px); }
}

#l13-book .quiz-fx {
  position: absolute;
  inset: 0;
  z-index: 6;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  pointer-events: none;
  border-radius: 12px;
  overflow: hidden;
}

#l13-book .quiz-fx[hidden] {
  display: none !important;
  visibility: hidden;
}

#l13-book .quiz-fx--success {
  background: rgba(236, 253, 245, 0.94);
}

#l13-book .quiz-fx--fail {
  background: rgba(254, 242, 242, 0.94);
}

#l13-book .quiz-fx-burst {
  position: absolute;
  width: 8rem;
  height: 8rem;
  border-radius: 50%;
  opacity: 0;
}

#l13-book .quiz-fx--success .quiz-fx-burst {
  background: radial-gradient(circle, rgba(45, 212, 191, 0.55) 0%, transparent 68%);
  animation: l13-quiz-burst 0.7s ease-out;
}

#l13-book .quiz-fx--fail .quiz-fx-burst {
  background: radial-gradient(circle, rgba(248, 113, 113, 0.5) 0%, transparent 68%);
  animation: l13-quiz-burst 0.65s ease-out;
}

@keyframes l13-quiz-burst {
  0% { transform: scale(0.2); opacity: 0.9; }
  100% { transform: scale(2.2); opacity: 0; }
}

#l13-book .quiz-fx-icon {
  position: relative;
  z-index: 1;
  font-size: clamp(3rem, 12vh, 5rem);
  font-weight: 900;
  line-height: 1;
}

#l13-book .quiz-fx--success .quiz-fx-icon {
  color: #047857;
  animation: l13-quiz-pop 0.55s cubic-bezier(0.34, 1.56, 0.64, 1);
}

#l13-book .quiz-fx--fail .quiz-fx-icon {
  color: #b91c1c;
  animation: l13-quiz-pop-shake 0.65s ease;
}

@keyframes l13-quiz-pop {
  0% { transform: scale(0.25); opacity: 0; }
  55% { transform: scale(1.12); opacity: 1; }
  100% { transform: scale(1); opacity: 1; }
}

@keyframes l13-quiz-pop-shake {
  0% { transform: scale(0.4); opacity: 0; }
  25% { transform: scale(1.08); opacity: 1; }
  40%, 60%, 80% { transform: translateX(-5px) scale(1); }
  50%, 70%, 90% { transform: translateX(5px) scale(1); }
  100% { transform: none; opacity: 1; }
}

#l13-book .quiz-fx-label {
  position: relative;
  z-index: 1;
  font-weight: 900;
  font-size: clamp(0.95rem, 1.6vh + 0.35rem, 1.15rem);
  color: #0f172a;
}

#l13-book .quiz-fx.is-playing {
  animation: l13-quiz-fx-in 0.2s ease;
}

@keyframes l13-quiz-fx-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

#l13-book .lesson-page[data-page="9"] .quiz-item .fb {
  flex-shrink: 0;
  margin: clamp(0.2rem, 0.8vh, 0.45rem) 0 0;
  padding: 0;
  font-size: clamp(0.72rem, 1vh + 0.28rem, 0.86rem);
  line-height: 1.35;
  min-height: 0;
  text-align: center;
}

#l13-book .lesson-page[data-page="9"] .quiz-item .fb:empty {
  display: none;
}

#l13-book .quiz-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.35rem;
  flex-shrink: 0;
}

#l13-book .quiz-progress {
  font-weight: 900;
  font-size: clamp(0.78rem, 1.1vh + 0.32rem, 0.92rem);
  color: var(--amber-ink, #92400e);
}

#l13-book .quiz-dots {
  flex: 1 1 auto;
  justify-content: flex-end;
  margin-top: 0;
  max-height: 4.5rem;
  overflow: hidden;
}

#l13-book .quiz-dots button {
  width: 1.65rem;
  height: 1.65rem;
  font-size: 0.62rem;
}

#l13-book .quiz-dots button.done {
  background: var(--ok-bg, #ecfdf5);
  border-color: var(--ok, #047857);
  color: var(--ok, #047857);
}

#l13-book .lesson-page[data-page="9"] .btn-row {
  padding-top: 0.2rem;
  flex-shrink: 0;
}

/* 屏 10 · 合句（16 题轮播，每题一屏） */
#l13-book .lesson-page[data-page="10"] {
  gap: 0.35rem;
}

#l13-book .lesson-page[data-page="10"] .page-head {
  padding-bottom: 0.2rem;
}

#l13-book .lesson-page[data-page="10"].active > .panel.panel-merge {
  overflow: hidden;
}

#l13-book .panel-merge {
  display: flex;
  flex-direction: column;
  min-height: 0;
  flex: 1 1 auto;
  overflow: hidden;
  gap: clamp(0.25rem, 0.8vh, 0.45rem);
}

#l13-book .merge-hint-box {
  flex-shrink: 0;
  padding: clamp(0.35rem, 1vh, 0.55rem);
  border-radius: 12px;
  border: 2px solid #fcd34d;
  background: linear-gradient(180deg, #fff, #fffbeb);
}

#l13-book .merge-hint-detail {
  margin: 0.25rem 0 0;
  font-size: clamp(0.72rem, 1.1vh + 0.3rem, 0.86rem);
  font-weight: 700;
  color: #78350f;
  line-height: 1.4;
}

#l13-book .merge-split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(0.35rem, 1vw, 0.65rem);
  flex: 1 1 auto;
  min-height: 0;
}

@media (max-width: 520px) {
  #l13-book .merge-split {
    grid-template-columns: 1fr;
  }
}

#l13-book .merge-clause {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
  padding: clamp(0.4rem, 1.2vh, 0.65rem);
  border-radius: 12px;
  border: 3px solid var(--edge, #5d4037);
  background: linear-gradient(145deg, #fff, #f8fafc);
}

#l13-book .merge-clause .merge-label {
  font-size: clamp(0.65rem, 0.9vh + 0.22rem, 0.75rem);
  font-weight: 900;
  color: #64748b;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.2rem;
}

#l13-book .merge-clause .en-line {
  font-size: clamp(0.82rem, 1.35vh + 0.38rem, 1.05rem);
  font-weight: 800;
  line-height: 1.38;
  margin: 0;
}

#l13-book .merge-reveal-slot {
  flex: 1 1 auto;
  min-height: clamp(72px, 14vh, 120px);
  display: flex;
  flex-direction: column;
  align-items: stretch;
  justify-content: center;
  border-radius: 14px;
  border: 3px dashed #c4b5fd;
  background: #faf5ff;
  padding: clamp(0.35rem, 1vh, 0.55rem);
  cursor: pointer;
  position: relative;
}

#l13-book .merge-reveal-btn {
  align-self: center;
  min-height: 44px;
  padding: 0.45rem 1rem;
  border-radius: 999px;
  border: 2px solid #7c3aed;
  background: #ede9fe;
  color: #5b21b6;
  font-weight: 900;
  font-size: clamp(0.78rem, 1.1vh + 0.32rem, 0.9rem);
  cursor: pointer;
  font-family: inherit;
  touch-action: manipulation;
}

#l13-book .merge-result {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
  padding: 0.2rem 0.35rem;
}

#l13-book .merge-result.is-covered {
  visibility: hidden;
  height: 0;
  flex: 0 0 0;
  padding: 0;
  overflow: hidden;
}

#l13-book .merge-result .en-line {
  font-size: clamp(0.88rem, 1.5vh + 0.42rem, 1.12rem);
  font-weight: 900;
  line-height: 1.4;
  margin: 0 0 0.2rem;
}

#l13-book .merge-result .zh-hint {
  margin: 0;
  font-size: clamp(0.72rem, 1.05vh + 0.3rem, 0.88rem);
  font-weight: 700;
  color: #475569;
  line-height: 1.35;
}

#l13-book .merge-use {
  flex-shrink: 0;
  margin: 0;
  font-size: clamp(0.68rem, 0.95vh + 0.26rem, 0.8rem);
  font-weight: 700;
  color: #0f766e;
  line-height: 1.35;
  padding: 0.25rem 0.45rem;
  border-radius: 8px;
  background: #f0fdfa;
}

#l13-book .merge-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.35rem;
  flex-shrink: 0;
}

#l13-book .merge-progress {
  font-weight: 900;
  font-size: clamp(0.78rem, 1.1vh + 0.32rem, 0.92rem);
  color: var(--amber-ink, #92400e);
}

#l13-book .merge-dots {
  flex: 1 1 auto;
  justify-content: flex-end;
  max-height: 4.5rem;
  overflow: hidden;
}

#l13-book .merge-dots button {
  width: 1.65rem;
  height: 1.65rem;
  font-size: 0.62rem;
}

/* 屏 11 · 通道 */
#l13-book .panel-channel {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  min-height: min(280px, 42vh);
}
#l13-book .channel-btn {
  display: block;
  width: 100%;
  max-width: 420px;
  margin: 0.5rem auto 0;
  min-height: 56px;
  padding: 0.85rem 1rem;
  border-radius: 14px;
  border: 3px solid var(--edge, #5d4037);
  font-weight: 900;
  font-size: 1rem;
  cursor: pointer;
  text-align: center;
  text-decoration: none;
  color: var(--amber-ink, #92400e);
  background: linear-gradient(135deg, #fde68a, #fcd34d);
  box-sizing: border-box;
}
#l13-book .panel-channel .channel-links {
  margin-top: 0.75rem;
  font-size: 0.86rem;
  font-weight: 700;
  color: #64748b;
}
#l13-book .panel-channel .channel-links a {
  color: var(--amber-ink, #92400e);
  font-weight: 900;
}

#l13-book .fb {
  color: var(--amber-ink, #92400e);
}