/**
 * L13 Page 04 · 辨析站（对齐 Page 03：全屏铺满、无滚动练习区、左图右文）
 */

#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: hidden;
}

#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, #eff6ff, #dbeafe);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border-radius: 12px 18px 10px 16px;
  border: 3px solid var(--edge, #5d4037);
}

#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 .panel-lead {
  font-weight: 800;
  margin: 0 0 0.25rem;
  line-height: 1.4;
  flex-shrink: 0;
  font-size: clamp(0.78rem, 1.4vh, 0.88rem);
}

#l13-book .tier-label {
  background: var(--past-bg, #dbeafe);
  color: #1e40af;
}
#l13-book .tier-label.tier-c {
  background: #fef3c7;
  color: #92400e;
}

#l13-book .rule-box.blue {
  background: var(--past-bg, #dbeafe);
  border-left: 5px solid var(--past, #1d4ed8);
  color: #1e3a8a;
  flex-shrink: 0;
}
#l13-book .rule-box.violet {
  background: var(--perf-bg, #ede9fe);
  border-left: 5px solid var(--perf, #6d28d9);
  color: #4c1d95;
  flex-shrink: 0;
}

#l13-book .hl-past {
  background: var(--past-bg, #dbeafe);
  color: var(--past, #1d4ed8);
  padding: 0 0.12rem;
  border-radius: 4px;
  font-weight: 900;
}
#l13-book .hl-perf {
  background: var(--perf-bg, #ede9fe);
  color: var(--perf, #6d28d9);
  padding: 0 0.12rem;
  border-radius: 4px;
  font-weight: 900;
}
#l13-book .hl-bad {
  background: var(--bad-bg, #fef2f2);
  color: var(--bad, #b91c1c);
  text-decoration: line-through;
}

#l13-book .btn.blue {
  background: linear-gradient(135deg, #3b82f6, #1d4ed8);
  color: #fff;
  border-color: #1e40af;
  box-shadow: 0 3px 0 rgba(30, 64, 175, 0.28);
}
#l13-book .btn.violet {
  background: linear-gradient(135deg, #8b5cf6, #6d28d9);
  color: #fff;
  border-color: #5b21b6;
  box-shadow: 0 3px 0 rgba(91, 33, 182, 0.28);
}

#l13-book .lesson-page.active > .panel:not(.panel-split) {
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#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 · 导图全屏 */
#l13-book .panel-intro-contrast {
  display: flex;
  flex-direction: column;
  min-height: 0;
  flex: 1 1 auto;
  overflow: hidden;
  padding: 0;
}
#l13-book .panel-intro-contrast .scene-frame--intro {
  flex: 1 1 auto;
  max-height: none !important;
  min-height: min(72vh, 640px);
  aspect-ratio: auto;
}

/* 屏 2 · 双轨 */
#l13-book .observe-pin {
  text-align: center;
  font-weight: 900;
  font-size: clamp(0.72rem, 1.1vh + 0.3rem, 0.86rem);
  color: #b45309;
  margin: 0;
  padding: 0.3rem 0.45rem;
  border-radius: 8px;
  background: #fef3c7;
  flex-shrink: 0;
}
#l13-book .dual-track {
  display: grid;
  gap: 0.4rem;
  flex: 1 1 auto;
  min-height: 0;
  align-content: stretch;
}
@media (min-width: 520px) {
  #l13-book .dual-track {
    grid-template-columns: 1fr 1fr;
  }
}
#l13-book .track-lane {
  padding: clamp(0.35rem, 1vh, 0.55rem);
  border-radius: 12px;
  border: 3px dashed;
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
}
#l13-book .track-lane.earlier {
  border-color: var(--perf, #6d28d9);
  background: var(--perf-bg, #ede9fe);
}
#l13-book .track-lane.observe {
  border-color: var(--past, #1d4ed8);
  background: var(--past-bg, #dbeafe);
}
#l13-book .track-lane h4 {
  margin: 0 0 0.25rem;
  font-size: clamp(0.68rem, 0.95vh + 0.24rem, 0.78rem);
  font-weight: 900;
  text-align: center;
}
#l13-book .track-lane.earlier h4 { color: var(--perf, #6d28d9); }
#l13-book .track-lane.observe h4 { color: var(--past, #1d4ed8); }
#l13-book .track-event {
  padding: 0.35rem 0.45rem;
  border-radius: 10px;
  background: #fff;
  font-weight: 800;
  font-size: clamp(0.75rem, 1.05vh + 0.3rem, 0.88rem);
  text-align: center;
  line-height: 1.32;
}

/* 屏 3 · 对比卡轮播 */
#l13-book .panel-contrast .stage-body {
  overflow: hidden;
}
#l13-book #contrast-visual,
#l13-book .panel-contrast .dual-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 .panel-contrast .dual-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 .panel-contrast .dual-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 .panel-contrast .dual-fig figcaption {
  flex-shrink: 0;
  font-size: clamp(0.68rem, 0.95vh + 0.22rem, 0.78rem);
  font-weight: 900;
  text-align: center;
  padding: 0.3rem 0.45rem;
  line-height: 1.35;
}

#l13-book .panel-contrast .dual-fig-a figcaption {
  background: #ede9fe;
  color: #5b21b6;
}

#l13-book .panel-contrast .dual-fig-b figcaption {
  background: #dbeafe;
  color: #1d4ed8;
}

#l13-book .carousel-card {
  padding: 0.75rem;
  border-radius: 14px;
  border: 3px solid #93c5fd;
  background: linear-gradient(180deg, #fff, #eff6ff);
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  overflow: hidden;
}
#l13-book .contrast-card {
  margin: 0;
  padding: 0;
  border: none;
  background: transparent;
}
#l13-book .contrast-card .line-past,
#l13-book .contrast-card .line-perf {
  margin: 0.35rem 0;
  padding-left: 0.55rem;
}
#l13-book .contrast-card .line-past {
  border-left: 4px solid var(--past, #1d4ed8);
}
#l13-book .contrast-card .line-perf {
  border-left: 4px solid var(--perf, #6d28d9);
}
#l13-book .line-tag {
  font-size: 0.68rem;
  font-weight: 900;
  color: #64748b;
}
#l13-book .carousel-dots {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  justify-content: center;
  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(--past, #1d4ed8);
  color: #fff;
  border-color: #1e40af;
}

/* 屏 4 · 语篇标色 */
#l13-book .lesson-page[data-page="4"].active > .panel.panel-story {
  overflow: hidden;
}
#l13-book .panel-story {
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
  gap: 0.3rem;
}
#l13-book .story-legend {
  flex-shrink: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  font-size: clamp(0.68rem, 1vh + 0.26rem, 0.78rem);
  font-weight: 800;
}
#l13-book .story-legend span {
  padding: 0.18rem 0.45rem;
  border-radius: 6px;
}
#l13-book .story-passage-wrap {
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}
#l13-book .story-passage {
  flex: 1 1 auto;
  min-height: 0;
  overflow-y: auto;
  padding: clamp(0.45rem, 1.2vh, 0.7rem);
  border-radius: 14px;
  border: 3px solid #c4b5fd;
  background: #faf5ff;
  font-size: clamp(0.82rem, 1.25vh + 0.35rem, 1rem);
  font-weight: 700;
  line-height: 1.55;
}
#l13-book .story-passage .tok {
  cursor: pointer;
  border-radius: 4px;
  padding: 0 0.1rem;
  transition: background 0.15s, color 0.15s;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}
#l13-book .story-passage .tok:hover {
  outline: 2px dashed rgba(37, 99, 235, 0.45);
  outline-offset: 2px;
}
#l13-book .story-passage .tok:focus-visible {
  outline: 3px solid var(--l13-accent, #2563eb);
  outline-offset: 2px;
}
#l13-book .story-passage .tok.past {
  background: var(--past-bg, #dbeafe);
  color: var(--past, #1d4ed8);
}
#l13-book .story-passage .tok.perf {
  background: var(--perf-bg, #ede9fe);
  color: var(--perf, #6d28d9);
}
#l13-book .panel-story .zh-hint {
  flex-shrink: 0;
  margin: 0;
}

/* 屏 5 · 改错网格 */
#l13-book .lesson-page[data-page="5"].active > .panel.panel-traps {
  overflow: hidden;
}
#l13-book .panel-traps {
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
  gap: 0.25rem;
}
#l13-book .trap-grid {
  display: grid;
  grid-template-columns: 1fr;
  grid-auto-rows: 1fr;
  gap: clamp(0.2rem, 0.5vh, 0.35rem);
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
  margin: 0;
  padding: 0;
  list-style: none;
}
@media (min-width: 720px) {
  #l13-book .trap-grid {
    grid-template-columns: 1fr 1fr;
  }
}
#l13-book .trap-item {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
  margin: 0;
  padding: clamp(0.28rem, 0.8vh, 0.45rem) clamp(0.35rem, 1vw, 0.55rem);
  border-radius: 10px;
  border: 2px solid #fecaca;
  background: #fff;
  overflow: hidden;
}
#l13-book .trap-item .trap-wrong {
  font-weight: 800;
  margin: 0;
  font-size: clamp(0.7rem, 1vh + 0.28rem, 0.82rem);
  line-height: 1.3;
}
#l13-book .trap-item .fix {
  display: none;
  margin-top: 0.2rem;
  font-weight: 800;
  font-size: clamp(0.65rem, 0.9vh + 0.22rem, 0.76rem);
  color: var(--ok, #047857);
  line-height: 1.3;
}
#l13-book .trap-item.revealed .fix {
  display: block;
}
#l13-book .trap-item .btn-trap {
  margin-top: 0.2rem;
  align-self: flex-start;
  min-height: 32px;
  padding: 0.2rem 0.55rem;
  font-size: 0.72rem;
}

/* 屏 6 · 观察点选择（每题一屏） */
#l13-book .lesson-page[data-page="6"] {
  gap: 0.35rem;
}

#l13-book .lesson-page[data-page="6"] .page-head {
  padding-bottom: 0.2rem;
}

#l13-book .lesson-page[data-page="6"].active > .panel.panel-observe {
  overflow: hidden;
}

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

#l13-book .lesson-page[data-page="6"] .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 .observe-slot,
#l13-book #observe-quiz {
  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="6"] .quiz-item {
  display: flex;
  flex-direction: column;
  justify-content: center;
  width: 100%;
  max-width: 52rem;
  flex: 1 1 auto;
  min-height: 0;
  margin: 0 auto;
  padding: clamp(0.45rem, 1.8vh, 1rem) clamp(0.5rem, 2vw, 1.1rem);
  overflow: hidden;
  border-radius: 12px;
  border: 2px solid #e2e8f0;
  background: #fff;
}

#l13-book .lesson-page[data-page="6"] .quiz-item.done {
  border-color: var(--ok, #047857);
  background: var(--ok-bg, #ecfdf5);
}

#l13-book .lesson-page[data-page="6"] .quiz-stem {
  font-weight: 800;
  margin: 0 0 clamp(0.3rem, 1.1vh, 0.65rem);
  font-size: clamp(0.88rem, 1.65vh + 0.38rem, 1.15rem);
  line-height: 1.38;
  text-align: center;
}

#l13-book .observe-blank {
  display: inline-block;
  min-width: 3.5rem;
  border-bottom: 2px dashed var(--l13-accent, #2563eb);
  padding: 0 0.15rem;
}

#l13-book .lesson-page[data-page="6"] .opt-row {
  display: flex;
  flex-direction: column;
  gap: clamp(0.28rem, 0.85vh, 0.5rem);
  margin-top: 0;
  width: 100%;
  max-width: 36rem;
  margin-left: auto;
  margin-right: auto;
}

#l13-book .lesson-page[data-page="6"] .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);
  text-align: center;
  white-space: normal;
  word-break: break-word;
  line-height: 1.28;
  cursor: pointer;
  font-family: inherit;
  touch-action: manipulation;
}

#l13-book .lesson-page[data-page="6"] .opt-row button:disabled {
  cursor: default;
}

#l13-book .lesson-page[data-page="6"] .opt-row button.ok {
  background: var(--ok-bg, #ecfdf5);
  border-color: var(--ok, #047857);
}

#l13-book .lesson-page[data-page="6"] .opt-row button.bad {
  background: var(--bad-bg, #fef2f2);
  border-color: var(--bad, #b91c1c);
}

#l13-book .lesson-page[data-page="6"] .quiz-item .fb:empty {
  display: none;
}

#l13-book .lesson-page[data-page="6"] .quiz-item .fb {
  font-size: clamp(0.72rem, 1vh + 0.28rem, 0.86rem);
  margin-top: clamp(0.2rem, 0.8vh, 0.45rem);
  text-align: center;
  line-height: 1.35;
}

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

#l13-book .observe-progress {
  font-weight: 900;
  font-size: clamp(0.78rem, 1.1vh + 0.32rem, 0.92rem);
  color: var(--l13-accent-ink, #1d4ed8);
}

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

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

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

#l13-book .lesson-page[data-page="6"] .btn-row {
  padding-top: 0.2rem;
  flex-shrink: 0;
}

/* 屏 7 · 对话 */
#l13-book .lesson-page[data-page="7"].active > .panel.panel-dialogue {
  overflow: hidden;
}
#l13-book .panel-dialogue {
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
  gap: 0.25rem;
}
#l13-book #dialogue-box {
  display: grid;
  grid-template-columns: 1fr;
  grid-auto-rows: 1fr;
  gap: clamp(0.22rem, 0.55vh, 0.38rem);
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
}
@media (min-width: 720px) {
  #l13-book #dialogue-box {
    grid-template-columns: 1fr 1fr;
  }
}
#l13-book .dialogue-pair {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
  margin: 0;
  padding: clamp(0.3rem, 0.85vh, 0.5rem);
  border-radius: 10px;
  border: 2px solid #e9d5ff;
  background: #faf5ff;
  overflow: hidden;
}
#l13-book .dialogue-pair .who {
  font-size: clamp(0.62rem, 0.85vh + 0.2rem, 0.72rem);
  font-weight: 900;
  color: #64748b;
  margin: 0 0 0.1rem;
}
#l13-book .dialogue-pair .en-line {
  margin: 0.1rem 0;
  font-size: clamp(0.72rem, 1.05vh + 0.3rem, 0.86rem);
  line-height: 1.32;
}
#l13-book .dialogue-pair .zh-hint {
  margin: 0.15rem 0 0;
  font-size: clamp(0.65rem, 0.9vh + 0.22rem, 0.76rem);
}
#l13-book .dialogue-pair .btn-speak-mini {
  margin-top: 0.2rem;
  align-self: flex-start;
  min-height: 30px;
  font-size: 0.72rem;
  padding: 0.18rem 0.5rem;
}

/* 屏 8 · 翻译 */
#l13-book .lesson-page[data-page="8"].active > .panel.panel-translate {
  overflow: hidden;
}
#l13-book .panel-translate {
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
}
#l13-book #translate-tier-c {
  display: grid;
  grid-template-columns: 1fr;
  grid-auto-rows: 1fr;
  gap: clamp(0.25rem, 0.55vh, 0.4rem);
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
}
@media (min-width: 720px) {
  #l13-book #translate-tier-c {
    grid-template-columns: 1fr 1fr 1fr;
  }
}
#l13-book .translate-item {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 0;
  margin: 0;
  padding: clamp(0.35rem, 1vh, 0.55rem);
  border-radius: 10px;
  border: 2px solid #fde68a;
  background: #fffbeb;
  overflow: hidden;
}
#l13-book .translate-item .translate-stem {
  font-weight: 800;
  font-size: clamp(0.75rem, 1.1vh + 0.3rem, 0.9rem);
  margin: 0 0 0.25rem;
  line-height: 1.35;
}
#l13-book .translate-item input {
  width: 100%;
  margin-top: 0.2rem;
  padding: 0.35rem 0.45rem;
  border-radius: 8px;
  border: 2px solid #cbd5e1;
  font-weight: 700;
  font-size: clamp(0.72rem, 1vh + 0.28rem, 0.85rem);
}
#l13-book .translate-item .ans {
  display: none;
  margin-top: 0.25rem;
  font-weight: 800;
  font-size: clamp(0.68rem, 0.95vh + 0.24rem, 0.8rem);
  color: var(--ok, #047857);
  line-height: 1.32;
}
#l13-book .translate-item.show .ans {
  display: block;
}
#l13-book .translate-item .btn-show-ans {
  margin-top: 0.2rem;
  align-self: flex-start;
  min-height: 32px;
  font-size: 0.72rem;
}

/* 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;
  flex: 1 1 auto;
  min-height: 0;
}
#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: #1e40af;
  background: linear-gradient(135deg, #bfdbfe, #93c5fd);
  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: #1e40af;
  font-weight: 900;
}

#l13-book .fb {
  color: #1e40af;
  font-weight: 700;
}