/**
 * L13 定语从句 · 现代课堂显示系统
 * 统一目录、课件、练习、拓展与讲义在桌面/投影屏上的比例、层级和交互反馈。
 */

:root {
  --l13-modern-navy: #0f172a;
  --l13-modern-ink: #172033;
  --l13-modern-muted: #64748b;
  --l13-modern-blue: #2563eb;
  --l13-modern-cyan: #0891b2;
  --l13-modern-teal: #0f766e;
  --l13-modern-violet: #7c3aed;
  --l13-modern-surface: rgba(255, 255, 255, 0.96);
  --l13-modern-line: rgba(148, 163, 184, 0.26);
  --l13-modern-shadow: 0 24px 70px rgba(15, 23, 42, 0.16);
  --l13-modern-shadow-soft: 0 10px 30px rgba(15, 23, 42, 0.09);
  --l13-modern-radius: 24px;
  --grammar-pager-accent: var(--l13-modern-teal);
  --grammar-pager-accent-ink: #115e59;
}

html {
  color-scheme: light;
}

body.l13rc-no-scroll {
  color: var(--l13-modern-ink);
  background:
    radial-gradient(circle at 8% 0%, rgba(56, 189, 248, 0.2), transparent 32%),
    radial-gradient(circle at 92% 8%, rgba(139, 92, 246, 0.14), transparent 30%),
    linear-gradient(145deg, #eaf7ff 0%, #f5f3ff 48%, #ecfdf5 100%) !important;
}

body.l13rc-no-scroll :is(a, button, input, select, textarea):focus-visible {
  outline: 3px solid #38bdf8 !important;
  outline-offset: 3px;
}

body.l13rc-no-scroll :is(button, a, .image-card, .choice-btn) {
  -webkit-tap-highlight-color: transparent;
}

/* 目录：取消旧版 161% 整页缩放；允许整页滚动以适配放大与长列表。 */
html.l13rc-no-scroll-root.g-index-scaled,
html.g-index-scaled:has(body.l13rc-no-scroll) {
  width: 100% !important;
  max-width: none !important;
  margin: 0 !important;
  zoom: 1 !important;
  height: auto !important;
  overflow-x: hidden !important;
  overflow-y: auto !important;
}

body.g-index-scaled.l13rc-no-scroll {
  min-height: 100dvh;
  height: auto !important;
  max-height: none !important;
  padding: clamp(18px, 2.4vw, 42px) !important;
  overflow-x: clip !important;
  overflow-y: auto !important;
}

body.g-index-scaled.l13rc-no-scroll .g-index {
  width: min(1440px, 100%) !important;
  max-width: 1440px !important;
  max-height: none !important;
  margin: 0 auto;
  padding: clamp(24px, 2.7vw, 44px) !important;
  border: 1px solid rgba(255, 255, 255, 0.72);
  border-radius: 30px;
  background: rgba(255, 255, 255, 0.93);
  box-shadow: 0 32px 90px rgba(2, 8, 23, 0.3);
  backdrop-filter: blur(22px);
  overflow: visible !important;
}

body.g-index-scaled.l13rc-no-scroll .g-index::before {
  height: 6px;
  margin: calc(clamp(24px, 2.7vw, 44px) * -1)
    calc(clamp(24px, 2.7vw, 44px) * -1) clamp(18px, 2vw, 28px);
  background: linear-gradient(90deg, #0ea5e9, #6366f1 52%, #10b981);
}

body.g-index-scaled.l13rc-no-scroll .g-index-logo {
  width: clamp(184px, 16vw, 250px);
  height: auto;
}

body.g-index-scaled.l13rc-no-scroll .g-index h1 {
  margin: 0.35rem 0 0.5rem;
  color: var(--l13-modern-navy);
  font-size: clamp(2rem, 2.5vw, 3rem);
  letter-spacing: -0.04em;
}

body.g-index-scaled.l13rc-no-scroll .g-index > .hint {
  margin: 0.8rem 0 1rem;
  padding: 0.75rem 1rem;
  border: 1px solid rgba(14, 165, 233, 0.24);
  border-radius: 14px;
  background: linear-gradient(90deg, rgba(224, 242, 254, 0.88), rgba(238, 242, 255, 0.82));
  color: #475569;
  font-size: clamp(0.9rem, 0.75vw, 1.05rem);
}

body.g-index-scaled.l13rc-no-scroll .g-index ol {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(10px, 1vw, 16px);
}

body.g-index-scaled.l13rc-no-scroll .g-index li {
  margin: 0;
}

body.g-index-scaled.l13rc-no-scroll .g-index li a {
  min-height: 84px;
  height: 100%;
  align-items: center;
  gap: 1rem;
  padding: 0.9rem 1rem;
  border: 1px solid var(--l13-modern-line);
  border-radius: 17px;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: 0 4px 14px rgba(15, 23, 42, 0.045);
}

body.g-index-scaled.l13rc-no-scroll .g-index li a:hover {
  border-color: rgba(37, 99, 235, 0.38);
  background: linear-gradient(135deg, #fff, #eff6ff);
  box-shadow: 0 14px 28px rgba(37, 99, 235, 0.12);
  transform: translateY(-3px);
}

body.g-index-scaled.l13rc-no-scroll .g-index .num {
  min-width: 2.8rem;
  height: 2.8rem;
  border-radius: 13px;
  background: linear-gradient(135deg, #dbeafe, #ede9fe);
  color: #3730a3;
  font-size: 0.92rem;
}

body.g-index-scaled.l13rc-no-scroll .g-index .label {
  color: var(--l13-modern-navy);
  font-size: clamp(1rem, 0.85vw, 1.18rem);
}

body.g-index-scaled.l13rc-no-scroll .g-index .desc {
  color: var(--l13-modern-muted);
  font-size: clamp(0.82rem, 0.68vw, 0.96rem);
}

body.g-index-scaled.l13rc-no-scroll .g-index .back {
  margin-top: 1rem;
  padding-top: 0.9rem;
}

/* 课件与练习的主舞台。 */
body.l13rc-demo-screen.has-lesson-pager > :is(.app-container, #app-frame) {
  border: 1px solid rgba(255, 255, 255, 0.78) !important;
  border-radius: var(--l13-modern-radius) !important;
  background: var(--l13-modern-surface) !important;
  box-shadow: var(--l13-modern-shadow) !important;
}

body.l13rc-demo-screen .app-container > .page {
  width: min(1640px, 100%);
  margin-inline: auto;
  padding: clamp(16px, 1.6vw, 30px) clamp(18px, 2.2vw, 40px) !important;
}

body.l13rc-demo-screen .app-container > .page > h1 {
  color: var(--l13-modern-navy);
  font-size: clamp(1.8rem, 2.25vw, 3rem) !important;
  letter-spacing: -0.035em;
}

body.l13rc-demo-screen .app-container .lead {
  color: var(--l13-modern-muted);
  font-size: clamp(1rem, 0.95vw, 1.3rem) !important;
}

body.l13rc-demo-screen .app-container :is(.sentence-block, .step-item) {
  border: 1px solid var(--l13-modern-line);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: var(--l13-modern-shadow-soft);
}

body.l13rc-demo-screen .app-container .sentence-block {
  font-size: clamp(1.08rem, 1.12vw, 1.55rem) !important;
  line-height: 1.62;
}

body.l13rc-demo-screen .app-container .question-box {
  border: 1px solid rgba(99, 102, 241, 0.22);
  border-radius: 18px;
  background: linear-gradient(135deg, #312e81 0%, #4f46e5 58%, #2563eb 100%);
  box-shadow: 0 16px 34px rgba(49, 46, 129, 0.2);
  font-size: clamp(1rem, 0.9vw, 1.25rem) !important;
}

body.l13rc-demo-screen .app-container :is(.reveal-btn, .welcome-btn, .guide-launch) {
  min-height: 48px;
  padding: 0.72rem 1.35rem;
  border-radius: 14px;
  background: linear-gradient(135deg, #0ea5e9, #2563eb);
  box-shadow: 0 8px 18px rgba(37, 99, 235, 0.22);
  font-size: clamp(0.92rem, 0.72vw, 1.06rem);
  font-weight: 800;
}

body.l13rc-demo-screen .app-container :is(.reveal-btn, .welcome-btn, .guide-launch):hover {
  filter: brightness(1.06);
  transform: translateY(-2px);
}

body.l13rc-demo-screen .app-container .page-actions {
  margin-top: auto;
  padding-top: 1rem;
}

body.l13rc-demo-screen .app-container .page-actions::before {
  content: "";
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, transparent, #cbd5e1);
}

body.l13rc-demo-screen .app-container .image-card {
  border: 1px solid var(--l13-modern-line);
  border-radius: 20px;
  box-shadow: var(--l13-modern-shadow-soft);
}

body.l13rc-demo-screen .app-container .image-card:hover {
  border-color: rgba(14, 165, 233, 0.48);
  box-shadow: 0 18px 38px rgba(14, 165, 233, 0.16);
}

/* 句子合并教学：演示与学生练习使用同一图片画布，并完整显示原图比例。 */
body.l13rc-demo-screen .app-container .p5-two-col {
  --l13rc-merge-media-h: clamp(230px, 30vh, 340px);
}

body.l13rc-demo-screen .app-container .p5-two-col .p5-left > .image-row,
body.l13rc-demo-screen .app-container .p5-two-col .p5-left > .image-card {
  width: 100% !important;
  height: var(--l13rc-merge-media-h) !important;
  min-height: var(--l13rc-merge-media-h) !important;
  max-height: var(--l13rc-merge-media-h) !important;
  margin: 0 0 clamp(12px, 1.4vh, 18px) !important;
}

body.l13rc-demo-screen .app-container .p5-two-col .p5-left > .image-row {
  grid-template-columns: 1fr !important;
  grid-template-rows: 1fr !important;
}

body.l13rc-demo-screen .app-container .p5-two-col .p5-left > .image-row .image-card,
body.l13rc-demo-screen .app-container .p5-two-col .p5-left > .image-card {
  width: 100%;
  height: 100%;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border: 1px solid var(--l13-modern-line);
  border-radius: 18px;
  background:
    linear-gradient(135deg, rgba(241, 245, 249, 0.88), rgba(255, 255, 255, 0.98));
}

body.l13rc-demo-screen.has-lesson-pager > .app-container .p5-two-col .p5-left > .image-row .image-card img,
body.l13rc-demo-screen.has-lesson-pager > .app-container .p5-two-col .p5-left > .image-card img {
  flex: 0 1 auto;
  display: block;
  width: auto !important;
  height: auto !important;
  max-width: 100% !important;
  max-height: 100% !important;
  object-fit: contain !important;
  object-position: center !important;
}

/* 两个原句、动态融合句和练习句统一使用课堂展示字号。 */
body.l13rc-demo-screen .app-container .p5-two-col .p5-left .sentence-block > p:not(.demo-title),
body.l13rc-demo-screen .app-container .p5-two-col .p5-left .p5-demo-line,
body.l13rc-demo-screen .app-container .p5-two-col .p5-left .p5-demo-build {
  display: block !important;
  margin-block: 0.55rem !important;
  font-size: clamp(1.25rem, 1.1vw + 0.55rem, 1.78rem) !important;
  font-weight: 750;
  line-height: 1.55 !important;
  white-space: normal !important;
  overflow-wrap: anywhere;
}

body.l13rc-demo-screen .app-container .p5-two-col .p5-left .p5-demo-build:empty {
  min-height: 2.3em;
}

body.l13rc-demo-screen .app-container .picture-pick-split {
  grid-template-columns: minmax(540px, 58%) minmax(360px, 42%);
  gap: clamp(24px, 2.4vw, 46px);
}

body.l13rc-demo-screen .app-container .picture-pick-text {
  padding: clamp(18px, 2vw, 34px);
  border: 1px solid rgba(148, 163, 184, 0.22);
  border-radius: 22px;
  background:
    radial-gradient(circle at 100% 0%, rgba(56, 189, 248, 0.12), transparent 38%),
    linear-gradient(145deg, rgba(248, 250, 252, 0.98), rgba(239, 246, 255, 0.9));
}

body.l13rc-demo-screen .app-container .picture-pick-images {
  grid-template-columns: repeat(2, minmax(0, 1fr)) !important;
  grid-template-rows: 1fr !important;
  min-height: min(55vh, 570px);
}

body.l13rc-demo-screen .app-container .page[data-page="0"] .picture-pick-images .image-card {
  height: 100%;
}

body.l13rc-demo-screen.has-lesson-pager > .app-container .page[data-page="0"] .picture-pick-images .image-card img {
  flex: 1 1 0;
  width: 100% !important;
  height: 100% !important;
  min-height: 0 !important;
  max-height: none !important;
  object-fit: cover !important;
  object-position: center 28%;
}

body.l13rc-demo-screen.has-lesson-pager > .app-container .page[data-page="0"] .picture-pick-images .image-card:nth-child(2) img {
  object-position: 72% center;
}

/* 朗读入口保持为句子旁的小型工具按钮；同一可见文本只保留一个。 */
body.l13rc-no-scroll .tts-btn,
body.grammar-handout-page .tts-chip {
  width: auto !important;
  min-width: 0 !important;
  min-height: 30px !important;
  max-height: 34px !important;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.25rem !important;
  margin: 0.3rem 0 0 !important;
  padding: 0.28rem 0.58rem !important;
  border: 1px solid rgba(14, 116, 144, 0.32) !important;
  border-radius: 999px !important;
  background: rgba(240, 249, 255, 0.96) !important;
  color: #075985 !important;
  box-shadow: 0 3px 9px rgba(14, 116, 144, 0.1) !important;
  font-size: clamp(0.72rem, 0.52vw, 0.82rem) !important;
  font-weight: 800 !important;
  line-height: 1 !important;
  vertical-align: middle;
}

body.l13rc-no-scroll .tts-btn:hover,
body.grammar-handout-page .tts-chip:hover {
  border-color: rgba(2, 132, 199, 0.52) !important;
  background: #e0f2fe !important;
  transform: translateY(-1px);
}

body.l13rc-no-scroll .tts-btn svg {
  width: 14px !important;
  height: 14px !important;
  flex: 0 0 14px;
}

body.l13rc-demo-screen .picture-pick-copy .question-box:has(> .sentence-play-btn) {
  position: relative;
  padding-right: clamp(4.5rem, 7vw, 6rem) !important;
}

body.l13rc-demo-screen .picture-pick-copy .question-box > .sentence-play-btn {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  margin: 0 !important;
}

body.grammar-handout-page .tts-chip {
  min-height: 24px !important;
  max-height: 26px !important;
  margin: 0 0 0 0.28rem !important;
  padding: 0.12rem 0.34rem !important;
  font-size: 0.68rem !important;
  box-shadow: none !important;
}

body.l13rc-no-scroll.l13rc-manual-tts .tts-btn.l13rc-tts-duplicate,
body.l13rc-no-scroll .l13rc-tts-duplicate {
  display: none !important;
}

/* 欢迎屏：减少空洞感并强化课程信息。 */
body.l13rc-demo-screen .page-welcome .welcome-wrapper,
body.l13rc-demo-screen #welcome-view {
  background:
    radial-gradient(circle at 20% 20%, rgba(56, 189, 248, 0.22), transparent 30%),
    radial-gradient(circle at 82% 16%, rgba(139, 92, 246, 0.18), transparent 28%),
    linear-gradient(145deg, #eff6ff, #f5f3ff 52%, #ecfdf5) !important;
}

body.l13rc-demo-screen .page-welcome .welcome-wrapper::before,
body.l13rc-demo-screen #welcome-view .welcome-card::before {
  content: "RC";
  display: grid;
  place-items: center;
  width: clamp(76px, 8vw, 116px);
  aspect-ratio: 1;
  margin: 0 auto clamp(14px, 2vh, 24px);
  border-radius: 30%;
  color: #fff;
  background: linear-gradient(145deg, #2563eb, #7c3aed);
  box-shadow: 0 16px 34px rgba(79, 70, 229, 0.28);
  font: 900 clamp(1.5rem, 2.8vw, 2.5rem) / 1 system-ui, sans-serif;
  letter-spacing: -0.06em;
}

body.l13rc-demo-screen #welcome-view .welcome-card {
  width: min(680px, 92vw);
  max-width: 680px;
  padding: clamp(28px, 4vw, 56px);
  border: 1px solid rgba(255, 255, 255, 0.82);
  border-radius: 28px;
  background: rgba(255, 255, 255, 0.86);
  box-shadow: var(--l13-modern-shadow);
  backdrop-filter: blur(20px);
}

body.l13rc-demo-screen #welcome-view .welcome-card > div:first-child {
  display: none;
}

body.l13rc-demo-screen #welcome-view .welcome-card h1 {
  margin: 0 0 0.65rem;
  color: var(--l13-modern-navy);
  font-size: clamp(2rem, 3.2vw, 3.2rem);
  letter-spacing: -0.04em;
}

/* 一题一屏练习：让题目成为视觉中心，而不是漂浮在大片空白里。 */
body.l13rc-practice-one #app-frame.practice-book {
  justify-content: flex-start;
  padding: clamp(18px, 2.2vw, 38px) clamp(24px, 4vw, 72px) !important;
}

body.l13rc-practice-one .practice-page {
  width: min(1420px, 100%);
  max-width: 1420px;
  justify-content: center;
}

body.l13rc-practice-one .practice-head {
  padding: 0 0 clamp(12px, 1.4vh, 20px);
}

body.l13rc-practice-one .practice-part-title {
  color: #0369a1;
  font-size: clamp(1.65rem, 2vw, 2.45rem);
}

body.l13rc-practice-one .practice-body {
  flex: 0 1 auto;
  width: 100%;
  min-height: min(32vh, 320px);
  margin-top: clamp(12px, 1.5vh, 22px);
  padding: clamp(24px, 3vw, 52px) clamp(28px, 4.5vw, 80px);
  border: 1px solid var(--l13-modern-line);
  border-radius: 24px;
  background:
    radial-gradient(circle at 100% 0%, rgba(14, 165, 233, 0.08), transparent 34%),
    rgba(255, 255, 255, 0.94);
  box-shadow: var(--l13-modern-shadow-soft);
}

body.l13rc-practice-one .practice-body .sentence-box {
  font-size: clamp(1.35rem, 1.55vw, 2rem) !important;
  line-height: 1.62;
}

body.l13rc-practice-one .practice-answer-toggle {
  min-height: 48px;
  border-radius: 14px;
}

/* 拓展练习/综合测验。 */
body.has-lesson-pager > #app {
  padding: clamp(10px, 1vw, 18px) clamp(12px, 1.3vw, 24px) !important;
}

#l13rc-book.book {
  border: 1px solid rgba(255, 255, 255, 0.75);
  border-radius: 26px;
  background: rgba(255, 255, 255, 0.94);
  box-shadow: var(--l13-modern-shadow);
}

#l13rc-book.book::before {
  display: none;
}

#l13rc-book .top-bar {
  margin: 12px 14px 0;
  padding: 12px 18px;
  border: 1px solid rgba(124, 58, 237, 0.25);
  border-radius: 16px;
  background: linear-gradient(90deg, #f5f3ff, #eff6ff);
}

#l13rc-book .top-bar strong {
  font-size: clamp(1.15rem, 1.2vw, 1.55rem);
}

#l13rc-book .top-bar .l13rc-index-link {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  padding: 0.55rem 1rem;
  border: 1px solid rgba(124, 58, 237, 0.35);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.88);
}

#l13rc-book .l13rc-scroll {
  padding: clamp(12px, 1.2vw, 20px) clamp(16px, 1.8vw, 30px) clamp(16px, 1.5vw, 24px);
}

#l13rc-book .page-head {
  padding: 0.2rem 0 0.7rem;
}

#l13rc-book .page-kicker {
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
  background: #ede9fe;
  color: #5b21b6;
  font-size: clamp(0.82rem, 0.62vw, 0.98rem);
}

#l13rc-book .page-title {
  font-size: clamp(1.45rem, 1.7vw, 2.15rem);
  letter-spacing: -0.025em;
}

#l13rc-book .panel {
  border: 1px solid var(--l13-modern-line);
  border-radius: 20px;
  padding: clamp(18px, 2vw, 34px);
  background: rgba(255, 255, 255, 0.96);
  box-shadow: var(--l13-modern-shadow-soft);
}

#l13rc-book .quiz-slot .quiz-item {
  max-width: min(1100px, 100%);
  padding: clamp(18px, 2vw, 32px);
  border: 1px solid rgba(13, 148, 136, 0.26);
  border-radius: 18px;
}

#l13rc-book :is(.quiz-slot .quiz-head, .quiz-stem, .en-line) {
  font-size: clamp(1.22rem, 1.35vw, 1.75rem) !important;
}

#l13rc-book .opt-row button {
  min-height: 52px;
  padding: 0.75rem 1rem;
  border: 1px solid var(--l13-modern-line);
  border-radius: 13px;
  font-size: clamp(1rem, 0.9vw, 1.22rem);
}

#l13rc-book .btn {
  min-height: 48px;
  border-width: 1px;
  border-radius: 13px;
  font-size: clamp(0.94rem, 0.72vw, 1.08rem);
}

/* 讲义：屏幕阅读使用宽版电子讲义，打印仍保持原 A4 规则。 */
@media screen {
  body.grammar-handout-page.l13rc-handout {
    --gh-sheet-max: min(1380px, calc(100vw - clamp(32px, 6vw, 112px)));
    font-size: clamp(16px, 0.42vw + 13px, 20px);
    padding-inline: clamp(16px, 3vw, 48px);
  }

  body.grammar-handout-page :is(
    .grammar-handout-top,
    .l13-handout-top,
    .grammar-handout-print-hint,
    .no-print-hint,
    .grammar-handout-pdf-bar,
    .handout-pdf-bar,
    .grammar-handout-section-nav,
    .handout-section-nav,
    main.sheet
  ) {
    width: var(--gh-sheet-max) !important;
    max-width: var(--gh-sheet-max) !important;
  }

  body.grammar-handout-page :is(.grammar-handout-top, .l13-handout-top) {
    margin-top: 1rem;
    padding: 12px 18px;
    border: 1px solid rgba(15, 118, 110, 0.34);
    border-radius: 16px;
    background: rgba(255, 255, 255, 0.88);
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.09);
    backdrop-filter: blur(16px);
  }

  body.grammar-handout-page .handout-section-nav {
    gap: 0.45rem;
    padding: 0.2rem 0;
  }

  body.grammar-handout-page .handout-section-nav a {
    min-height: 38px;
    display: inline-flex;
    align-items: center;
    padding: 0.45rem 0.75rem;
    border-width: 1px;
    font-size: clamp(0.76rem, 0.55vw, 0.9rem);
  }

  body.grammar-handout-page main.sheet.l13rc-handout {
    padding: clamp(28px, 3vw, 52px) clamp(28px, 4vw, 64px) clamp(48px, 5vw, 80px);
    border: 1px solid rgba(14, 165, 233, 0.34);
    border-radius: 26px;
    background: rgba(255, 255, 255, 0.96);
    box-shadow: var(--l13-modern-shadow);
  }

  body.grammar-handout-page main.sheet::before {
    display: none;
  }

  body.grammar-handout-page.l13rc-handout .handout-cover {
    margin: 0 0 clamp(24px, 3vw, 42px);
    padding: clamp(42px, 5vw, 76px) clamp(24px, 4vw, 60px);
    border-radius: 22px;
  }

  body.grammar-handout-page.l13rc-handout .handout-cover__inner {
    max-width: 48rem;
  }

  body.grammar-handout-page.l13rc-handout .handout-cover__title {
    font-size: clamp(2.4rem, 4vw, 4.2rem);
  }

  body.grammar-handout-page.l13rc-handout h2.section-title {
    margin-top: 1.8rem;
    font-size: clamp(1.3rem, 1.35vw, 1.75rem);
  }

  body.grammar-handout-page.l13rc-handout :is(.example, .cloze-item, .lesson-flow ol, .hw-list) {
    font-size: clamp(0.98rem, 0.62vw, 1.12rem);
  }

  body.grammar-handout-page.l13rc-handout table.data {
    font-size: clamp(0.92rem, 0.58vw, 1.06rem);
  }

  body.grammar-handout-page.l13rc-handout .card {
    padding: 1rem 1.15rem;
    border: 1px solid var(--l13-modern-line);
    border-radius: 16px;
    box-shadow: 0 7px 18px rgba(15, 23, 42, 0.055);
  }
}

/* 底部导航：投影环境下保持可辨识、可点击。 */
@media screen and (min-width: 900px) {
  :root {
    --grammar-pager-gap: 4rem;
    --grammar-pager-logo-slot: clamp(7rem, 12vw, 10rem);
    --l13rc-file-pager-h: 4rem;
    --practice-stepper-h: 4rem;
  }

  body.has-lesson-pager nav.lesson-pager,
  body.has-lesson-pager nav.lesson-footer-nav,
  body.has-lesson-pager #app nav.lesson-pager {
    min-height: 58px;
    padding: 0.45rem clamp(0.75rem, 2vw, 2rem);
    gap: 0.75rem;
    border-top: 1px solid rgba(15, 118, 110, 0.24);
    background: rgba(255, 255, 255, 0.9);
    box-shadow: 0 -12px 32px rgba(15, 23, 42, 0.1);
    backdrop-filter: blur(18px);
  }

  body.has-lesson-pager nav.lesson-pager > :is(.pager-prev, .pager-next, .pager-muted),
  body.has-lesson-pager nav.lesson-pager .pager-zone > :is(.pager-prev, .pager-next, .pager-mid) {
    min-height: 44px;
    max-height: none;
    padding: 0.55rem 1rem;
    border-width: 1px;
    border-radius: 12px;
    font-size: clamp(0.85rem, 0.65vw, 1rem);
  }

  body.has-lesson-pager nav.lesson-pager .pager-logo img {
    width: clamp(112px, 9vw, 150px);
    max-height: 44px;
    object-fit: contain;
  }

  body.l13rc-practice-one .practice-pager {
    min-height: 58px;
    padding: 0.45rem clamp(0.75rem, 2vw, 2rem);
    border-top: 1px solid rgba(14, 165, 233, 0.22);
    background: rgba(248, 250, 252, 0.94);
    box-shadow: 0 -10px 24px rgba(14, 165, 233, 0.08);
    backdrop-filter: blur(16px);
  }
}

@media screen and (min-width: 1600px) and (min-height: 850px) {
  :root {
    --lesson-fs-html: clamp(19px, 0.38vw + 14px, 22px);
  }

  body.l13rc-demo-screen .app-container {
    --font-size-lead: clamp(1.18rem, 0.8vw, 1.45rem);
    --font-size-h1: clamp(2rem, 2.25vw, 3.15rem);
    --font-size-h2: clamp(1.35rem, 1.35vw, 1.85rem);
  }
}

@media screen and (max-width: 899px) {
  body.g-index-scaled.l13rc-no-scroll {
    padding: 12px !important;
  }

  body.g-index-scaled.l13rc-no-scroll .g-index {
    padding: 20px 16px 24px !important;
    border-radius: 22px;
  }

  body.g-index-scaled.l13rc-no-scroll .g-index::before {
    margin: -20px -16px 18px;
  }

  body.g-index-scaled.l13rc-no-scroll .g-index ol {
    grid-template-columns: 1fr;
  }

  body.g-index-scaled.l13rc-no-scroll .g-index li a {
    min-height: 70px;
  }

  body.l13rc-demo-screen .app-container .picture-pick-split {
    grid-template-columns: 1fr;
  }

  body.l13rc-demo-screen .app-container .p5-two-col {
    --l13rc-merge-media-h: clamp(190px, 29vh, 270px);
  }

  body.l13rc-demo-screen .app-container .p5-two-col .p5-left .sentence-block > p:not(.demo-title),
  body.l13rc-demo-screen .app-container .p5-two-col .p5-left .p5-demo-line,
  body.l13rc-demo-screen .app-container .p5-two-col .p5-left .p5-demo-build {
    font-size: clamp(1.05rem, 4.5vw, 1.35rem) !important;
  }

  body.l13rc-demo-screen .app-container .picture-pick-copy {
    width: 100% !important;
    max-width: 100% !important;
    transform: none !important;
  }

  body.l13rc-demo-screen .app-container .picture-pick-text {
    max-height: none !important;
    overflow: visible !important;
  }

  body.l13rc-demo-screen .picture-pick-copy .question-box:has(> .sentence-play-btn) {
    padding-right: clamp(14px, 2vw, 24px) !important;
  }

  body.l13rc-demo-screen .picture-pick-copy .question-box > .sentence-play-btn {
    position: static;
    margin-top: 0.55rem !important;
  }

  body.l13rc-demo-screen .app-container .picture-pick-images {
    min-height: clamp(220px, 34vh, 360px);
  }

  body.l13rc-practice-one .practice-body {
    min-height: 0;
    padding: 20px 18px;
  }
}

/* —— 语料中心：例句 / 辨析 / 应用三段式 —— */
@media screen {
  body.l13rc-corpus-hub-page {
    min-height: 100dvh;
    display: block !important;
    overflow-y: auto !important;
    background: #eef2f7 !important;
    font-family: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  }

  .corpus-hub {
    width: min(1420px, calc(100% - clamp(24px, 5vw, 80px)));
    margin: 0 auto;
    padding: clamp(24px, 3vw, 46px) 0 60px;
  }

  .corpus-hub__head {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 1.5rem;
    padding: clamp(22px, 3vw, 42px);
    border-radius: 20px;
    background: #14213d;
    color: #fff;
  }

  .corpus-hub__eyebrow {
    margin: 0 0 0.65rem;
    color: #93c5fd;
    font-size: 0.72rem;
    font-weight: 900;
    letter-spacing: 0.14em;
  }

  .corpus-hub__head h1 {
    margin: 0;
    font-size: clamp(2rem, 3.4vw, 3.6rem);
    line-height: 1.08;
    letter-spacing: -0.055em;
  }

  .corpus-hub__head p:not(.corpus-hub__eyebrow) {
    margin: 0.75rem 0 0;
    color: #cbd5e1;
    font-size: clamp(0.92rem, 0.8vw, 1.08rem);
  }

  .corpus-hub__back {
    flex: 0 0 auto;
    padding: 0.65rem 0.9rem;
    border: 1px solid rgba(255, 255, 255, 0.22);
    border-radius: 10px;
    color: #fff;
    font-size: 0.82rem;
    font-weight: 800;
    text-decoration: none;
  }

  .corpus-hub__tabs {
    position: sticky;
    top: 0;
    z-index: 20;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.5rem;
    margin: 1rem 0;
    padding: 0.5rem;
    border: 1px solid #dbe3ee;
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.94);
    backdrop-filter: blur(14px);
  }

  .corpus-hub__tabs button {
    min-height: 46px;
    border: 0;
    border-radius: 10px;
    background: transparent;
    color: #64748b;
    font: 800 0.92rem/1 system-ui, sans-serif;
    cursor: pointer;
  }

  .corpus-hub__tabs button span {
    margin-right: 0.4rem;
    color: #94a3b8;
    font-size: 0.68rem;
  }

  .corpus-hub__tabs button[aria-selected="true"] {
    background: #2563eb;
    color: #fff;
  }

  .corpus-hub__tabs button[aria-selected="true"] span {
    color: #bfdbfe;
  }

  .corpus-hub__panel {
    padding: clamp(22px, 3vw, 42px);
    border: 1px solid #dbe3ee;
    border-radius: 20px;
    background: #fff;
  }

  .corpus-hub__panel[hidden] {
    display: none !important;
  }

  .corpus-hub__section-head {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1.4rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid #e2e8f0;
  }

  .corpus-hub__section-head span,
  .corpus-contrast-card header span {
    color: #2563eb;
    font-size: 0.72rem;
    font-weight: 900;
    letter-spacing: 0.08em;
  }

  .corpus-hub__section-head h2 {
    margin: 0.25rem 0 0;
    color: #172033;
    font-size: clamp(1.45rem, 2vw, 2rem);
    letter-spacing: -0.035em;
  }

  .corpus-hub__section-head > p {
    max-width: 34rem;
    margin: 0;
    color: #64748b;
    text-align: right;
    font-size: 0.88rem;
  }

  .corpus-topic-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 1rem;
  }

  .corpus-topic {
    min-width: 0;
    overflow: hidden;
    border: 1px solid #dbe3ee;
    border-radius: 16px;
    background: #f8fafc;
  }

  .corpus-topic > header {
    padding: 1rem;
    border-bottom: 1px solid #dbe3ee;
    background: #fff;
  }

  .corpus-topic > header span {
    color: #2563eb;
    font-size: 0.72rem;
    font-weight: 900;
  }

  .corpus-topic > header h3 {
    margin: 0.18rem 0;
    color: #172033;
    font-size: 1.15rem;
  }

  .corpus-topic > header p {
    margin: 0;
    color: #64748b;
    font-size: 0.78rem;
    line-height: 1.45;
  }

  .corpus-topic__list {
    display: grid;
    gap: 0.55rem;
    padding: 0.7rem;
  }

  .corpus-example {
    padding: 0.78rem;
    border-radius: 11px;
    background: #fff;
  }

  .corpus-example__tier {
    color: #94a3b8;
    font-size: 0.62rem;
    font-weight: 900;
  }

  .corpus-example__en {
    margin: 0.25rem 0 0;
    color: #172033;
    font-size: clamp(0.92rem, 0.75vw, 1.06rem);
    font-weight: 750;
    line-height: 1.48;
  }

  .corpus-example__zh {
    margin: 0.22rem 0 0;
    color: #64748b;
    font-size: 0.76rem;
    line-height: 1.4;
  }

  .corpus-contrast-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
  }

  .corpus-contrast-card {
    padding: 1rem;
    border: 1px solid #dbe3ee;
    border-radius: 15px;
    background: #f8fafc;
  }

  .corpus-contrast-card:last-child {
    grid-column: 1 / -1;
  }

  .corpus-contrast-card h3 {
    margin: 0.2rem 0 0.8rem;
    color: #172033;
    font-size: 1.18rem;
  }

  .corpus-rule-list {
    display: grid;
    gap: 0.55rem;
  }

  .corpus-rule {
    display: grid;
    grid-template-columns: minmax(9rem, 0.75fr) 1.5fr;
    gap: 1rem;
    align-items: center;
    padding: 0.75rem;
    border-radius: 10px;
    background: #fff;
  }

  .corpus-rule strong,
  .corpus-rule span {
    display: block;
  }

  .corpus-rule strong {
    color: #1d4ed8;
  }

  .corpus-rule span {
    margin-top: 0.18rem;
    color: #64748b;
    font-size: 0.74rem;
  }

  .corpus-rule p {
    margin: 0;
    color: #172033;
    font-weight: 700;
    line-height: 1.45;
  }

  .corpus-comma-rules {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.7rem;
    margin: 0;
    padding: 0;
    list-style: none;
  }

  .corpus-comma-rules li {
    padding: 0.85rem;
    border-radius: 10px;
    background: #fff;
    color: #334155;
    line-height: 1.5;
  }

  .corpus-merge-steps {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.7rem;
    margin: 0 0 1rem;
    padding: 0;
    list-style: none;
  }

  .corpus-merge-steps li {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.75rem;
    border-radius: 11px;
    background: #eff6ff;
    color: #1e3a5f;
    font-size: 0.82rem;
  }

  .corpus-merge-steps li span {
    flex: 0 0 auto;
    width: 26px;
    height: 26px;
    display: grid;
    place-items: center;
    border-radius: 50%;
    background: #2563eb;
    color: #fff;
    font-weight: 900;
  }

  .corpus-apply-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.8rem;
  }

  .corpus-drill {
    position: relative;
    padding: 1rem;
    border: 1px solid #dbe3ee;
    border-radius: 14px;
    background: #fff;
  }

  .corpus-drill__num {
    color: #94a3b8;
    font-size: 0.68rem;
    font-weight: 900;
  }

  .corpus-drill__source {
    margin: 0.35rem 0 0.75rem;
    color: #172033;
    font-size: 1.02rem;
    font-weight: 750;
    line-height: 1.5;
  }

  .corpus-drill details {
    border-top: 1px solid #e2e8f0;
    padding-top: 0.65rem;
  }

  .corpus-drill summary {
    color: #2563eb;
    font-size: 0.8rem;
    font-weight: 850;
    cursor: pointer;
  }

  .corpus-drill__answer {
    margin: 0.7rem 0 0;
    color: #047857;
    font-weight: 800;
    line-height: 1.5;
  }

  .corpus-drill__hint {
    margin: 0.3rem 0 0;
    color: #64748b;
    font-size: 0.8rem;
  }

  .corpus-theme-section {
    margin-top: 1.4rem;
  }

  .corpus-hub__section-head--compact {
    margin-bottom: 0.8rem;
  }

  .corpus-theme-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.6rem;
  }

  .corpus-theme {
    display: grid;
    grid-template-columns: 3.5rem 1fr;
    gap: 0.75rem;
    align-items: start;
    padding: 0.8rem;
    border-radius: 11px;
    background: #f8fafc;
  }

  .corpus-theme > span {
    padding: 0.22rem 0.4rem;
    border-radius: 999px;
    background: #dbeafe;
    color: #1d4ed8;
    font-size: 0.68rem;
    font-weight: 900;
    text-align: center;
  }

  .corpus-theme p {
    margin: 0;
    color: #172033;
    font-weight: 750;
    line-height: 1.45;
  }

  .corpus-theme small {
    display: block;
    margin-top: 0.18rem;
    color: #64748b;
    line-height: 1.4;
  }

  .corpus-zk__intro {
    margin: 0 0 1rem;
    color: #64748b;
    font-size: 0.88rem;
    line-height: 1.55;
  }

  .corpus-zk__years {
    display: grid;
    gap: 0.75rem;
  }

  .corpus-zk__year {
    border: 1px solid #dbe3ee;
    border-radius: 14px;
    background: #fff;
    overflow: hidden;
  }

  .corpus-zk__year > summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.9rem 1rem;
    cursor: pointer;
    list-style: none;
    font-weight: 800;
    color: #172033;
  }

  .corpus-zk__year > summary::-webkit-details-marker {
    display: none;
  }

  .corpus-zk__year-label {
    font-size: 1rem;
  }

  .corpus-zk__year-meta {
    color: #64748b;
    font-size: 0.78rem;
    font-weight: 700;
  }

  .corpus-zk__year-body {
    display: grid;
    gap: 0.7rem;
    padding: 0 0.85rem 0.85rem;
  }

  .corpus-zk__card {
    padding: 0.85rem 0.9rem;
    border: 1px solid #e8edf5;
    border-radius: 12px;
    background: #f8fafc;
  }

  .corpus-zk__card-head {
    display: flex;
    flex-wrap: wrap;
    gap: 0.35rem 0.55rem;
    align-items: center;
    margin-bottom: 0.55rem;
  }

  .corpus-zk__badge,
  .corpus-zk__paper,
  .corpus-zk__relation {
    padding: 0.14rem 0.45rem;
    border-radius: 999px;
    font-size: 0.68rem;
    font-weight: 800;
  }

  .corpus-zk__badge {
    background: #dbeafe;
    color: #1d4ed8;
  }

  .corpus-zk__badge.is-fill10 { background: #fef3c7; color: #b45309; }
  .corpus-zk__badge.is-fill5 { background: #ede9fe; color: #6d28d9; }
  .corpus-zk__badge.is-chart { background: #dcfce7; color: #047857; }
  .corpus-zk__badge.is-cloze { background: #fee2e2; color: #b91c1c; }

  .corpus-zk__paper {
    background: #e2e8f0;
    color: #334155;
  }

  .corpus-zk__relation {
    background: #eff6ff;
    color: #2563eb;
  }

  .corpus-zk__sentence {
    margin: 0 0 0.45rem;
    color: #172033;
    font-size: 1rem;
    font-weight: 750;
    line-height: 1.55;
  }

  .corpus-zk__context {
    margin: 0 0 0.65rem;
    color: #64748b;
    font-size: 0.8rem;
    line-height: 1.5;
  }

  .corpus-zk__actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
  }

  .corpus-zk__action {
    border: 1px solid #cbd5e1;
    border-radius: 999px;
    background: #fff;
    color: #334155;
    padding: 0.32rem 0.7rem;
    font-size: 0.76rem;
    font-weight: 800;
    cursor: pointer;
  }

  .corpus-zk__action.is-active,
  .corpus-zk__action:hover {
    border-color: #2563eb;
    background: #eff6ff;
    color: #1d4ed8;
  }

  .corpus-zk__panel {
    margin-top: 0.7rem;
    padding: 0.75rem 0.8rem;
    border-radius: 10px;
    background: #fff;
    border: 1px solid #dbe3ee;
  }

  .corpus-zk__panel h4 {
    margin: 0 0 0.45rem;
    color: #172033;
    font-size: 0.82rem;
  }

  .corpus-zk__panel ol {
    margin: 0;
    padding-left: 1.2rem;
    color: #334155;
    line-height: 1.55;
  }

  .corpus-zk__structure p {
    margin: 0.2rem 0;
    color: #334155;
    line-height: 1.5;
  }

  .corpus-zk__sentence--hl {
    font-size: 1.05rem;
  }

  .corpus-zk__hl.is-antecedent {
    background: #fef3c7;
    color: #92400e;
    padding: 0 0.12rem;
    border-radius: 4px;
  }

  .corpus-zk__hl.is-relation {
    background: #dcfce7;
    color: #047857;
    padding: 0 0.12rem;
    border-radius: 4px;
    font-weight: 800;
  }

  .corpus-zk__hl.is-clause {
    background: #eff6ff;
    color: #1d4ed8;
    padding: 0 0.12rem;
    border-radius: 4px;
  }

  .corpus-zk__hl.is-prep {
    background: #ede9fe;
    color: #6d28d9;
    padding: 0 0.12rem;
    border-radius: 4px;
  }

  .corpus-zk__hl.is-fill {
    background: #fff7ed;
    color: #c2410c;
    padding: 0 0.12rem;
    border-radius: 4px;
    font-weight: 700;
    border-bottom: 2px solid #fb923c;
  }

  .corpus-zk__meta,
  .corpus-zk__zh {
    margin: 0.35rem 0 0;
    color: #334155;
    line-height: 1.55;
  }
}

@media screen and (max-width: 900px) {
  .corpus-hub {
    width: min(100% - 20px, 720px);
    padding-top: 10px;
  }

  .corpus-hub__head,
  .corpus-hub__section-head {
    align-items: flex-start;
    flex-direction: column;
  }

  .corpus-hub__section-head > p {
    text-align: left;
  }

  .corpus-topic-grid,
  .corpus-contrast-grid,
  .corpus-apply-grid,
  .corpus-theme-list {
    grid-template-columns: 1fr;
  }

  .corpus-zk__actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

  .corpus-contrast-card:last-child {
    grid-column: auto;
  }

  .corpus-comma-rules,
  .corpus-merge-steps {
    grid-template-columns: 1fr 1fr;
  }

  .corpus-rule {
    grid-template-columns: 1fr;
    gap: 0.35rem;
  }
}

/* 课程目录的四段主线。 */
@media screen {
  body.g-index-scaled.l13rc-no-scroll .l13rc-route {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0.65rem;
    margin: 0 0 1rem;
  }

  body.g-index-scaled.l13rc-no-scroll .l13rc-route article {
    position: relative;
    min-width: 0;
    padding: 0.8rem 0.85rem;
    border: 1px solid #dbe3ee;
    border-radius: 13px;
    background: #f8fafc;
  }

  body.g-index-scaled.l13rc-no-scroll .l13rc-route span {
    display: block;
    margin-bottom: 0.28rem;
    color: #2563eb;
    font-size: 0.68rem;
    font-weight: 900;
  }

  body.g-index-scaled.l13rc-no-scroll .l13rc-route strong,
  body.g-index-scaled.l13rc-no-scroll .l13rc-route small {
    display: block;
  }

  body.g-index-scaled.l13rc-no-scroll .l13rc-route strong {
    color: #172033;
    font-size: 0.95rem;
  }

  body.g-index-scaled.l13rc-no-scroll .l13rc-route small {
    margin-top: 0.15rem;
    overflow: hidden;
    color: #64748b;
    font-size: 0.72rem;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  body.g-index-scaled.l13rc-no-scroll .l13rc-section-label {
    margin: 0.8rem 0 0.5rem;
    color: #64748b;
    font-size: 0.72rem;
    font-weight: 900;
    letter-spacing: 0.08em;
    text-transform: uppercase;
  }
}

@media screen and (max-width: 700px) {
  body.g-index-scaled.l13rc-no-scroll .l13rc-route {
    grid-template-columns: 1fr 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  body.l13rc-no-scroll *,
  body.l13rc-no-scroll *::before,
  body.l13rc-no-scroll *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* ========================================================================== 
   L13 · Clarity Refresh
   以“内容先于装饰、一步一个主操作”为原则统一课件、练习、测验与讲义。
   ========================================================================== */
@media screen {
  /* 本讲取消所有可见朗读/发音入口，避免按钮干扰教学主线。 */
  body.l13rc-no-scroll :is(.tts-btn, .sentence-play-btn, .tts-chip),
  body.grammar-handout-page :is(.tts-btn, .tts-chip) {
    display: none !important;
  }

  body.l13rc-no-scroll {
    --l13rc-clean-bg: #f3f6fa;
    --l13rc-clean-surface: #ffffff;
    --l13rc-clean-soft: #f8fafc;
    --l13rc-clean-line: #dbe3ee;
    --l13rc-clean-text: #162033;
    --l13rc-clean-muted: #667085;
    --l13rc-clean-accent: #2563eb;
    --l13rc-clean-accent-soft: #eff6ff;
    background: var(--l13rc-clean-bg) !important;
    color: var(--l13rc-clean-text);
  }

  /* —— 课件：去掉“卡片套卡片”，聚焦单一教学舞台 —— */
  body.l13rc-demo-screen.has-lesson-pager {
    --lesson-pager-gap: 0px !important;
    padding-bottom: max(4px, env(safe-area-inset-bottom, 0px)) !important;
    background: #e9eef5 !important;
  }

  body.l13rc-demo-screen > nav.lesson-pager.is-file-nav {
    display: none !important;
  }

  body.l13rc-demo-screen.has-lesson-pager > .app-container {
    border: 0 !important;
    border-radius: 18px !important;
    background: var(--l13rc-clean-surface) !important;
    box-shadow: 0 12px 36px rgba(15, 23, 42, 0.09) !important;
  }

  body.l13rc-demo-screen .app-container > .page {
    padding: clamp(18px, 2vw, 34px) clamp(22px, 3vw, 54px) !important;
  }

  body.l13rc-demo-screen .app-container > .page > h1 {
    margin: 0 0 0.35rem !important;
    color: #172033;
    font-size: clamp(1.65rem, 2vw, 2.45rem) !important;
    letter-spacing: -0.035em;
  }

  body.l13rc-demo-screen .app-container .lead {
    margin: 0 0 clamp(12px, 1.4vh, 20px) !important;
    color: var(--l13rc-clean-muted);
    font-size: clamp(0.98rem, 0.75vw, 1.15rem) !important;
  }

  body.l13rc-demo-screen .app-container :is(.sentence-block, .step-item) {
    border: 1px solid var(--l13rc-clean-line) !important;
    border-radius: 14px !important;
    background: var(--l13rc-clean-surface) !important;
    box-shadow: none !important;
  }

  body.l13rc-demo-screen .app-container .question-box {
    border: 1px solid #bfdbfe !important;
    border-left: 5px solid var(--l13rc-clean-accent) !important;
    border-radius: 12px !important;
    background: var(--l13rc-clean-accent-soft) !important;
    color: #1e3a5f !important;
    box-shadow: none !important;
  }

  body.l13rc-demo-screen .app-container .question-box :is(p, strong, .focus-sentence) {
    color: inherit !important;
  }

  body.l13rc-demo-screen .app-container .step-list {
    display: flex;
    flex-direction: column;
    gap: 0.55rem;
    padding-left: 0.35rem;
    border-left: 2px solid #dbeafe;
  }

  body.l13rc-demo-screen .app-container .step-item {
    margin: 0 !important;
    padding: 0.72rem 0.85rem !important;
  }

  body.l13rc-demo-screen .app-container .step-item::before {
    width: 28px !important;
    height: 28px !important;
    background: #dbeafe !important;
    color: #1d4ed8 !important;
    font-size: 0.82rem !important;
    box-shadow: 0 0 0 4px #fff;
  }

  /* 步骤内重复按钮交给页面唯一“显示下一步”控制。 */
  body.l13rc-demo-screen .app-container .step-item .reveal-btn,
  body.l13rc-demo-screen .app-container .p5-right .question-box .reveal-btn,
  body.l13rc-demo-screen .app-container .image-row > .sentence-play-btn,
  body.l13rc-demo-screen .app-container .step-item > .sentence-play-btn,
  body.l13rc-demo-screen #guide-toolbar,
  body.l13rc-demo-screen #global-replay-btn,
  body.l13rc-demo-screen .l13rc-action-hidden {
    display: none !important;
  }

  body.l13rc-demo-screen .app-container .page-actions {
    min-height: 48px;
    margin: auto 0 0 !important;
    padding-top: clamp(10px, 1.2vh, 16px) !important;
    display: flex;
    justify-content: flex-end !important;
    gap: 0.55rem !important;
    border-top: 1px solid #edf1f6;
  }

  body.l13rc-demo-screen .app-container .page-actions::before {
    display: none !important;
  }

  body.l13rc-demo-screen .app-container .page-actions .reveal-btn {
    width: auto !important;
    min-width: 8.5rem;
    min-height: 40px !important;
    margin: 0 !important;
    padding: 0.55rem 1rem !important;
    border: 1px solid #2563eb !important;
    border-radius: 10px !important;
    background: #2563eb !important;
    color: #fff !important;
    box-shadow: none !important;
    font-size: 0.9rem !important;
  }

  body.l13rc-demo-screen .app-container .page-actions .l13rc-action-next-page {
    min-width: 6.5rem;
    border-color: #cbd5e1 !important;
    background: #fff !important;
    color: #334155 !important;
  }

  body.l13rc-demo-screen .app-container .image-card {
    border-color: var(--l13rc-clean-line) !important;
    border-radius: 14px !important;
    box-shadow: none !important;
  }

  body.l13rc-demo-screen .app-container .image-card:hover {
    border-color: #93c5fd !important;
    box-shadow: none !important;
    transform: none !important;
  }

  body.l13rc-demo-screen .picture-pick-text {
    border: 1px solid var(--l13rc-clean-line) !important;
    border-radius: 14px !important;
    background: var(--l13rc-clean-soft) !important;
  }

  body.l13rc-demo-screen .status-chip {
    min-height: 34px !important;
    padding: 0.35rem 0.7rem !important;
    background: transparent !important;
    color: #475569 !important;
    font-size: 0.82rem !important;
  }

  body.l13rc-demo-screen .choice-btns {
    gap: 0.5rem !important;
  }

  body.l13rc-demo-screen .yesno-btn {
    min-width: 72px !important;
    min-height: 36px !important;
    padding: 0.4rem 0.75rem !important;
    border-radius: 9px !important;
    box-shadow: none !important;
  }

  body.l13rc-demo-screen .l13rc-lesson-progress {
    position: absolute;
    top: 14px;
    right: 18px;
    z-index: 30;
    padding: 0.32rem 0.68rem;
    border: 1px solid #dbe3ee;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.94);
    color: #475569;
    font-size: 0.76rem;
    font-weight: 800;
    letter-spacing: 0.02em;
    box-shadow: 0 4px 14px rgba(15, 23, 42, 0.06);
  }

  body.l13rc-demo-screen .l13rc-lesson-progress[hidden] {
    display: none !important;
  }

  body.l13rc-demo-screen .l13rc-course-home {
    position: absolute;
    top: 14px;
    left: 18px;
    z-index: 30;
    padding: 0.32rem 0.68rem;
    border: 1px solid #dbe3ee;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.94);
    color: #475569;
    font-size: 0.76rem;
    font-weight: 800;
    text-decoration: none;
    box-shadow: 0 4px 14px rgba(15, 23, 42, 0.06);
  }

  /* —— 练习：开门即做题，单题舞台 + 单一底栏 —— */
  body.l13rc-practice-one.has-lesson-pager {
    --l13rc-file-pager-h: 0px;
    --practice-stepper-h: 4rem;
    --lesson-pager-gap: var(--practice-stepper-h) !important;
    background: #eef2f7 !important;
  }

  body.l13rc-practice-one #welcome-view,
  body.l13rc-practice-one > .print-btn,
  body.l13rc-practice-one > nav.lesson-pager.is-file-nav {
    display: none !important;
  }

  body.l13rc-practice-one #app-frame.practice-book {
    border: 0 !important;
    border-radius: 18px !important;
    background: #fff !important;
    box-shadow: 0 12px 36px rgba(15, 23, 42, 0.08) !important;
  }

  body.l13rc-practice-one .practice-page {
    gap: 0.75rem !important;
  }

  body.l13rc-practice-one .practice-head {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    align-items: center;
    gap: 0.4rem 0.85rem;
    padding-bottom: 0.8rem !important;
    text-align: left !important;
    border-bottom: 1px solid var(--l13rc-clean-line) !important;
  }

  body.l13rc-practice-one .practice-kicker {
    grid-row: 1 / span 2;
    margin: 0 !important;
    padding: 0.35rem 0.6rem;
    border-radius: 9px;
    background: #eff6ff;
    color: #1d4ed8;
    font-size: 0.78rem !important;
  }

  body.l13rc-practice-one .practice-part-title {
    margin: 0 !important;
    color: var(--l13rc-clean-text) !important;
    font-family: inherit !important;
    font-size: clamp(1.15rem, 1.4vw, 1.55rem) !important;
  }

  body.l13rc-practice-one .practice-instruction {
    margin: 0 !important;
    color: var(--l13rc-clean-muted) !important;
    font-size: 0.88rem !important;
  }

  body.l13rc-practice-one .practice-body {
    border: 0 !important;
    border-radius: 0 !important;
    background: #fff !important;
    box-shadow: none !important;
  }

  body.l13rc-practice-one .practice-body .choice-btn {
    border: 1px solid var(--l13rc-clean-line) !important;
    border-radius: 10px !important;
    box-shadow: none !important;
  }

  body.l13rc-practice-one .practice-pager {
    bottom: 0 !important;
    min-height: 58px !important;
    display: none;
    grid-template-columns: auto minmax(7rem, 1fr) auto minmax(7rem, 1fr);
    align-items: center;
    gap: 0.5rem;
    padding: 0.45rem clamp(0.75rem, 2vw, 1.5rem) !important;
    border-top: 1px solid var(--l13rc-clean-line) !important;
    background: rgba(255, 255, 255, 0.96) !important;
    box-shadow: 0 -8px 22px rgba(15, 23, 42, 0.07) !important;
  }

  body.l13rc-practice-one .practice-pager.is-visible {
    display: grid !important;
  }

  body.l13rc-practice-one .practice-home {
    min-height: 38px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.4rem 0.7rem;
    border-radius: 9px;
    color: #475569;
    font-size: 0.78rem;
    font-weight: 800;
    text-decoration: none;
    white-space: nowrap;
  }

  body.l13rc-practice-one .practice-pager button {
    min-height: 38px !important;
    border: 1px solid #cbd5e1 !important;
    border-radius: 9px !important;
    background: #fff !important;
    color: #334155 !important;
    box-shadow: none !important;
  }

  body.l13rc-practice-one .practice-pager #practice-next {
    border-color: #2563eb !important;
    background: #2563eb !important;
    color: #fff !important;
  }

  body.l13rc-practice-one .practice-pager .practice-mid {
    min-height: 38px;
    border: 0 !important;
    background: transparent !important;
    color: #475569 !important;
    font-size: 0.82rem !important;
  }

  /* —— 拓展/测验：去“书本装饰”，只留题干、选项和必要导航 —— */
  #l13rc-book.book {
    border: 0 !important;
    border-radius: 18px !important;
    background: #fff !important;
    box-shadow: 0 12px 36px rgba(15, 23, 42, 0.08) !important;
  }

  #l13rc-book .top-bar {
    margin: 0 !important;
    padding: 14px 20px !important;
    border: 0 !important;
    border-bottom: 1px solid var(--l13rc-clean-line) !important;
    border-radius: 0 !important;
    background: #fff !important;
  }

  #l13rc-book .page-head {
    align-items: center !important;
    border-bottom: 0 !important;
  }

  #l13rc-book .page-title {
    color: var(--l13rc-clean-text) !important;
  }

  #l13rc-book .page-kicker {
    background: #eff6ff !important;
    color: #1d4ed8 !important;
  }

  #l13rc-book .panel {
    border: 0 !important;
    border-radius: 14px !important;
    background: #f8fafc !important;
    box-shadow: none !important;
  }

  #l13rc-book .quiz-slot .quiz-item {
    border: 1px solid var(--l13rc-clean-line) !important;
    border-radius: 14px !important;
    background: #fff !important;
    box-shadow: none !important;
  }

  #l13rc-book .carousel-dots {
    display: none !important;
  }

  #l13rc-book .btn-row {
    justify-content: flex-end;
  }

  #l13rc-book .btn-row .btn {
    min-height: 38px !important;
    padding: 0.45rem 0.8rem !important;
    border: 1px solid #cbd5e1 !important;
    border-radius: 9px !important;
    background: #fff !important;
    color: #334155 !important;
    box-shadow: none !important;
  }

  #l13rc-book .btn-row .btn:last-child {
    border-color: #2563eb !important;
    background: #2563eb !important;
    color: #fff !important;
  }

  /* —— 讲义：减少顶部 chrome 与装饰层 —— */
  body.grammar-handout-page.l13rc-handout {
    background: #eef2f7 !important;
  }

  body.grammar-handout-page :is(.grammar-handout-print-hint, .no-print-hint) {
    margin-block: 0.35rem !important;
    color: #64748b !important;
    font-size: 0.72rem !important;
  }

  body.grammar-handout-page :is(.grammar-handout-top, .l13-handout-top) {
    border: 1px solid var(--l13rc-clean-line) !important;
    border-radius: 12px !important;
    background: #fff !important;
    box-shadow: none !important;
  }

  body.grammar-handout-page .handout-section-nav {
    max-height: 42px;
    flex-wrap: nowrap !important;
    justify-content: flex-start !important;
    overflow-x: auto;
    scrollbar-width: none;
  }

  body.grammar-handout-page .handout-section-nav::-webkit-scrollbar {
    display: none;
  }

  body.grammar-handout-page main.sheet.l13rc-handout {
    border: 0 !important;
    border-radius: 18px !important;
    background: #fff !important;
    box-shadow: 0 12px 36px rgba(15, 23, 42, 0.08) !important;
  }

  body.grammar-handout-page.l13rc-handout .card {
    border: 1px solid var(--l13rc-clean-line) !important;
    border-radius: 12px !important;
    background: #fff !important;
    box-shadow: none !important;
  }

  /* —— 统一七步句子融合动态画布 —— */
  body.l13rc-demo-screen .l13rc-legacy-merge-hidden {
    display: none !important;
  }

  body.l13rc-demo-screen .l13rc-merge-stage {
    overflow: hidden;
    margin-top: 0.85rem;
    border: 1px solid #dbe3ee;
    border-radius: 14px;
    background: #fff;
  }

  body.l13rc-demo-screen .l13rc-merge-stage > header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.72rem 0.85rem;
    border-bottom: 1px solid #e2e8f0;
    background: #f8fafc;
  }

  body.l13rc-demo-screen .l13rc-merge-stage > header span,
  body.l13rc-demo-screen .l13rc-merge-stage > header strong {
    display: block;
  }

  body.l13rc-demo-screen .l13rc-merge-stage > header > div:first-child > span {
    margin-bottom: 0.15rem;
    color: #2563eb;
    font-size: 0.66rem;
    font-weight: 900;
    letter-spacing: 0.08em;
  }

  body.l13rc-demo-screen .l13rc-merge-stage > header strong {
    color: #172033;
    font-size: 0.9rem;
  }

  body.l13rc-demo-screen .l13rc-merge-dots {
    display: flex;
    gap: 0.25rem;
  }

  body.l13rc-demo-screen .l13rc-merge-dots span {
    width: 22px;
    height: 22px;
    display: grid;
    place-items: center;
    border-radius: 50%;
    background: #e2e8f0;
    color: #64748b;
    font-size: 0.62rem;
    font-weight: 900;
  }

  body.l13rc-demo-screen .l13rc-merge-dots span.is-done {
    background: #dbeafe;
    color: #1d4ed8;
  }

  body.l13rc-demo-screen .l13rc-merge-dots span.is-active {
    background: #2563eb;
    color: #fff;
    box-shadow: 0 0 0 4px #dbeafe;
  }

  body.l13rc-demo-screen .l13rc-merge-canvas {
    min-height: 13rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 0.75rem;
    padding: clamp(16px, 2vw, 28px);
  }

  body.l13rc-demo-screen :is(.l13rc-merge-originals, .l13rc-merge-process) {
    padding: 0.75rem 0.85rem;
    border: 1px solid #e2e8f0;
    border-radius: 11px;
  }

  body.l13rc-demo-screen .l13rc-merge-originals {
    background: #f8fafc;
  }

  body.l13rc-demo-screen .l13rc-merge-process {
    min-height: 5.5rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
    background: #fff;
  }

  body.l13rc-demo-screen :is(.l13rc-merge-originals, .l13rc-merge-process) > span {
    display: block;
    margin-bottom: 0.45rem;
    color: #64748b;
    font-size: 0.66rem;
    font-weight: 900;
    letter-spacing: 0.07em;
  }

  body.l13rc-demo-screen .l13rc-merge-placeholder {
    margin: 0;
    color: #64748b;
    font-size: 0.86rem;
    font-weight: 700;
  }

  body.l13rc-demo-screen .l13rc-merge-pair {
    display: grid;
    gap: 0.5rem;
  }

  body.l13rc-demo-screen .l13rc-merge-pair p,
  body.l13rc-demo-screen .l13rc-merge-role p,
  body.l13rc-demo-screen .l13rc-merge-build {
    margin: 0;
    color: #172033;
    font-size: clamp(1.15rem, 1.25vw, 1.65rem);
    font-weight: 780;
    line-height: 1.55;
  }

  body.l13rc-demo-screen .l13rc-merge-pair b {
    display: inline-grid;
    place-items: center;
    width: 1.55rem;
    height: 1.55rem;
    margin-right: 0.38rem;
    border-radius: 50%;
    background: #eff6ff;
    color: #1d4ed8;
    font-size: 0.72rem;
  }

  body.l13rc-demo-screen .l13rc-merge-role {
    display: grid;
    grid-template-columns: 4rem 1fr;
    gap: 0.7rem;
    align-items: center;
    padding: 0.55rem 0;
  }

  body.l13rc-demo-screen .l13rc-merge-role + .l13rc-merge-role {
    border-top: 1px solid #edf1f6;
  }

  body.l13rc-demo-screen .l13rc-merge-role > span {
    padding: 0.3rem 0.45rem;
    border-radius: 8px;
    background: #dbeafe;
    color: #1d4ed8;
    font-size: 0.74rem;
    font-weight: 900;
    text-align: center;
  }

  body.l13rc-demo-screen .l13rc-merge-role.is-support > span {
    background: #ede9fe;
    color: #6d28d9;
  }

  body.l13rc-demo-screen :is(.is-common, .is-antecedent) {
    padding: 0.06em 0.2em;
    border-radius: 5px;
    background: #fef3c7;
    color: #92400e;
  }

  body.l13rc-demo-screen .is-inserted {
    padding: 0.06em 0.2em;
    border-radius: 5px;
    background: #ede9fe;
    color: #6d28d9;
  }

  body.l13rc-demo-screen .is-duplicate {
    padding: 0.06em 0.2em;
    border: 2px solid #fca5a5;
    border-radius: 5px;
    color: #b91c1c;
  }

  body.l13rc-demo-screen .is-deleted {
    position: relative;
    padding: 0.06em 0.2em;
    border-radius: 5px;
    background: #fee2e2;
    color: #b91c1c;
    text-decoration: line-through 3px;
  }

  body.l13rc-demo-screen .is-deleted::after {
    content: "×";
    position: absolute;
    top: -0.9em;
    right: -0.55em;
    width: 1.15em;
    height: 1.15em;
    display: grid;
    place-items: center;
    border-radius: 50%;
    background: #dc2626;
    color: #fff;
    font-size: 0.72em;
    line-height: 1;
  }

  body.l13rc-demo-screen .is-relation {
    padding: 0.06em 0.24em;
    border-radius: 5px;
    background: #dcfce7;
    color: #047857;
  }

  body.l13rc-demo-screen .is-relation-wrong {
    padding: 0.06em 0.24em;
    border-radius: 5px;
    background: #fee2e2;
    color: #b91c1c;
    font-weight: 800;
    border: 2px dashed #f87171;
  }

  body.l13rc-demo-screen .is-prep-split {
    padding: 0.06em 0.24em;
    border-radius: 5px;
    background: #fef3c7;
    color: #b45309;
    font-weight: 800;
  }

  body.l13rc-demo-screen .l13rc-merge-build.is-final {
    color: #065f46;
    font-size: clamp(1.28rem, 1.45vw, 1.85rem);
  }

  body.l13rc-demo-screen .l13rc-merge-note {
    margin: 0.65rem 0 0;
    color: #64748b;
    font-size: 0.8rem;
    font-weight: 700;
  }

  body.l13rc-demo-screen .l13rc-merge-note.is-warning {
    color: #b45309;
  }

  body.l13rc-demo-screen .l13rc-merge-note.is-success {
    color: #047857;
  }

  body.l13rc-demo-screen .l13rc-merge-stage.is-updating .l13rc-merge-canvas {
    animation: l13rcMergeStageIn 0.3s ease;
  }

  @keyframes l13rcMergeStageIn {
    from { opacity: 0.35; transform: translateY(6px); }
    to { opacity: 1; transform: none; }
  }
}

@media screen and (max-width: 899px) {
  body.l13rc-demo-screen .l13rc-lesson-progress {
    top: 8px;
    right: 10px;
    font-size: 0.68rem;
  }

  body.l13rc-demo-screen .l13rc-course-home {
    top: 8px;
    left: 10px;
    font-size: 0.68rem;
  }

  body.l13rc-demo-screen .app-container .page-actions {
    flex-direction: row !important;
  }

  body.l13rc-demo-screen .app-container .page-actions .reveal-btn {
    flex: 1 1 0;
    min-width: 0;
  }

  body.l13rc-practice-one .practice-pager {
    grid-template-columns: auto 1fr auto;
  }

  body.l13rc-practice-one .practice-home {
    grid-column: 1 / -1;
    min-height: 26px;
    padding: 0.15rem 0.4rem;
  }

  body.l13rc-demo-screen .l13rc-merge-stage > header {
    align-items: flex-start;
    flex-direction: column;
  }

  body.l13rc-demo-screen .l13rc-merge-dots span {
    width: 19px;
    height: 19px;
  }

  body.l13rc-demo-screen .l13rc-merge-canvas {
    min-height: 11rem;
    padding: 14px;
  }

  body.l13rc-demo-screen :is(.l13rc-merge-originals, .l13rc-merge-process) {
    padding: 0.65rem;
  }

  body.l13rc-demo-screen .l13rc-merge-pair p,
  body.l13rc-demo-screen .l13rc-merge-role p,
  body.l13rc-demo-screen .l13rc-merge-build {
    font-size: clamp(1rem, 4.2vw, 1.25rem);
  }
}

/* 拓展页：who 与 whom 对比思考 */
body.l13rc-demo-screen .l13rc-who-whom-board {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  gap: clamp(14px, 1.6vw, 22px);
  align-items: start;
  margin-bottom: clamp(12px, 1.4vh, 18px);
}

body.l13rc-demo-screen .l13rc-who-whom-examples {
  display: flex;
  flex-direction: column;
  gap: clamp(10px, 1.2vh, 14px);
}

body.l13rc-demo-screen .l13rc-who-whom-card {
  padding: clamp(14px, 1.4vw, 18px);
  border-radius: 16px;
  border: 1px solid var(--l13rc-clean-line, #e2e8f0);
  background: #fff;
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.05);
}

body.l13rc-demo-screen .l13rc-who-whom-card.is-subject {
  border-left: 5px solid #0ea5e9;
  background: linear-gradient(135deg, rgba(224, 242, 254, 0.55), #fff 58%);
}

body.l13rc-demo-screen .l13rc-who-whom-card.is-object {
  border-left: 5px solid #8b5cf6;
  background: linear-gradient(135deg, rgba(237, 233, 254, 0.62), #fff 58%);
}

body.l13rc-demo-screen .l13rc-who-whom-tag {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.62rem;
  border-radius: 999px;
  background: rgba(15, 23, 42, 0.06);
  color: #334155;
  font-size: clamp(0.82rem, 0.7vw, 0.95rem);
  font-weight: 800;
  letter-spacing: 0.02em;
}

body.l13rc-demo-screen .l13rc-who-whom-sentence {
  margin: 0.72rem 0 0.45rem;
  font-size: clamp(1.08rem, 1vw + 0.45rem, 1.45rem) !important;
  font-weight: 750;
  line-height: 1.55;
}

body.l13rc-demo-screen .l13rc-who-whom-sentence .modifier {
  color: #047857;
  font-weight: 800;
}

body.l13rc-demo-screen .l13rc-who-whom-note {
  margin: 0;
  color: #64748b;
  font-size: clamp(0.9rem, 0.75vw, 1.02rem);
  line-height: 1.5;
}

body.l13rc-demo-screen .l13rc-who-whom-steps {
  min-width: 0;
}

body.l13rc-demo-screen .l13rc-who-whom-steps-title {
  margin: 0 0 0.65rem;
  padding: 0.45rem 0.15rem;
  color: #1e3a5f;
  font-size: clamp(0.95rem, 0.8vw, 1.08rem);
  font-weight: 800;
}

body.l13rc-demo-screen .l13rc-who-whom-steps .step-item.is-answer {
  border-color: rgba(16, 185, 129, 0.28);
  background: rgba(236, 253, 245, 0.92);
}

body.l13rc-demo-screen .l13rc-who-whom-steps .step-item.is-answer strong {
  color: #047857;
}

body.l13rc-demo-screen .l13rc-who-whom-practice {
  margin-top: clamp(10px, 1.2vh, 16px);
  padding: clamp(14px, 1.4vw, 18px);
  border: 1px solid #bfdbfe;
  border-left: 5px solid #2563eb;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(239, 246, 255, 0.95), #fff 70%);
}

body.l13rc-demo-screen .l13rc-who-whom-practice-title {
  margin: 0 0 0.55rem;
  color: #1e3a5f;
}

body.l13rc-demo-screen .l13rc-who-whom-practice-pair {
  display: grid;
  gap: 0.35rem;
  margin-bottom: 0.55rem;
}

body.l13rc-demo-screen .l13rc-who-whom-practice-pair .p5-demo-line {
  margin: 0;
  font-size: clamp(1rem, 0.95vw, 1.2rem) !important;
  font-weight: 700;
}

body.l13rc-demo-screen .l13rc-who-whom-practice-hint,
body.l13rc-demo-screen .l13rc-who-whom-practice-ans {
  margin: 0.45rem 0 0;
  line-height: 1.55;
}

body.l13rc-demo-screen .l13rc-who-whom-practice-ans {
  font-size: clamp(1.02rem, 0.95vw, 1.28rem) !important;
  font-weight: 750;
}

body.l13rc-demo-screen .l13rc-who-whom-practice-ans .modifier {
  color: #7c3aed;
  font-weight: 800;
}

@media (max-width: 900px) {
  body.l13rc-demo-screen .l13rc-who-whom-board {
    grid-template-columns: 1fr;
  }
}