:root {
  color-scheme: light;
  --bg: #f7f4ec;
  --surface: #fffdf8;
  --surface-2: #efeadd;
  --text: #18342f;
  --muted: #65746e;
  --line: #dcd8cd;
  --green: #0a6b58;
  --green-2: #bce0ce;
  --lime: #d6f06f;
  --orange: #f39a60;
  --red: #d5523f;
  --shadow: 0 24px 70px rgba(35, 65, 55, 0.1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 95% 10%, rgba(214, 240, 111, 0.2), transparent 24rem),
    var(--bg);
  color: var(--text);
  font-family: Inter, "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  line-height: 1.7;
}

button,
textarea,
input {
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.topbar {
  position: sticky;
  z-index: 20;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
  padding: 0 max(5vw, 24px);
  border-bottom: 1px solid rgba(220, 216, 205, 0.75);
  background: rgba(247, 244, 236, 0.88);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: var(--text);
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 39px;
  height: 39px;
  place-items: center;
  border-radius: 12px 12px 12px 3px;
  background: var(--green);
  color: white;
  font-family: Georgia, serif;
  font-size: 22px;
  font-style: italic;
}

.brand strong,
.brand small {
  display: block;
  line-height: 1.25;
}

.brand small {
  color: var(--muted);
  font-size: 11px;
}

.top-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.level-pill {
  padding: 5px 12px;
  border: 1px solid var(--green-2);
  border-radius: 999px;
  color: var(--green);
  font-size: 12px;
  font-weight: 800;
}

.icon-button {
  width: 38px;
  height: 38px;
  border: 0;
  border-radius: 50%;
  background: var(--surface-2);
  color: var(--text);
  cursor: pointer;
}

.progress-track {
  position: fixed;
  z-index: 30;
  top: 74px;
  left: 0;
  width: 100%;
  height: 3px;
}

.progress-track span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--orange);
}

main {
  overflow: hidden;
}

.hero {
  display: grid;
  min-height: 690px;
  padding: 90px max(8vw, 36px) 80px;
  grid-template-columns: minmax(0, 1.1fr) minmax(360px, 0.9fr);
  gap: 70px;
  align-items: center;
}

.eyebrow,
.section-heading > p {
  margin: 0 0 14px;
  color: var(--orange);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.16em;
}

.hero h1 {
  max-width: 800px;
  margin: 0;
  font-family: Georgia, "Songti SC", serif;
  font-size: clamp(54px, 6.4vw, 92px);
  font-weight: 500;
  letter-spacing: -0.055em;
  line-height: 1.05;
}

.hero h1 em {
  color: var(--green);
  font-weight: inherit;
}

.hero-en {
  margin: 20px 0 18px;
  color: var(--green);
  font-family: Georgia, serif;
  font-size: clamp(18px, 2vw, 28px);
  font-style: italic;
}

.hero-summary {
  max-width: 650px;
  margin: 0;
  color: var(--muted);
  font-size: 16px;
}

.hero-meta {
  display: flex;
  gap: 28px;
  margin: 30px 0;
  color: var(--muted);
  font-size: 13px;
}

.hero-meta b {
  color: var(--text);
  font-family: Georgia, serif;
  font-size: 22px;
}

.primary-button {
  display: inline-flex;
  align-items: center;
  gap: 24px;
  padding: 13px 18px 13px 24px;
  border-radius: 999px;
  background: var(--green);
  color: white;
  font-size: 14px;
  font-weight: 800;
  text-decoration: none;
  box-shadow: 0 14px 30px rgba(10, 107, 88, 0.22);
}

.primary-button span {
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.16);
}

.hero-art {
  position: relative;
  min-height: 500px;
}

.phone {
  position: absolute;
  z-index: 4;
  top: 30px;
  left: 50%;
  width: 230px;
  height: 440px;
  padding: 13px;
  transform: translateX(-50%) rotate(8deg);
  border: 2px solid var(--text);
  border-radius: 42px;
  background: #133d35;
  box-shadow: 24px 30px 0 var(--green-2), 0 40px 70px rgba(35, 65, 55, 0.25);
}

.phone-speaker {
  position: absolute;
  z-index: 2;
  top: 20px;
  left: 50%;
  width: 62px;
  height: 18px;
  transform: translateX(-50%);
  border-radius: 30px;
  background: #133d35;
}

.phone-screen {
  position: relative;
  display: grid;
  overflow: hidden;
  width: 100%;
  height: 100%;
  place-content: center;
  border-radius: 31px;
  background:
    linear-gradient(155deg, rgba(255,255,255,.5), transparent 45%),
    var(--lime);
  text-align: center;
}

.phone-screen p {
  margin: 0;
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.2em;
}

.phone-screen strong {
  font-family: Georgia, serif;
  font-size: 46px;
}

.focus-dot {
  width: 90px;
  height: 90px;
  margin: 0 auto 22px;
  border: 20px solid var(--green);
  border-radius: 50%;
  box-shadow: 0 0 0 12px rgba(10, 107, 88, 0.15);
}

.signal {
  position: absolute;
  border-radius: 50%;
  background: var(--orange);
  animation: float 4s ease-in-out infinite;
}

.signal-one { top: 70px; left: 30px; width: 13px; height: 13px; }
.signal-two { right: 24px; bottom: 90px; width: 23px; height: 23px; animation-delay: -1s; }
.signal-three { right: 50px; top: 95px; width: 8px; height: 8px; animation-delay: -2s; }

.orbit {
  position: absolute;
  top: 50%;
  left: 50%;
  border: 1px dashed rgba(10, 107, 88, 0.35);
  border-radius: 50%;
  transform: translate(-50%, -50%);
}

.orbit-one { width: 430px; height: 430px; }
.orbit-two { width: 560px; height: 330px; transform: translate(-50%, -50%) rotate(-20deg); }

.float-tag {
  position: absolute;
  z-index: 5;
  padding: 8px 14px;
  border: 1px solid rgba(24, 52, 47, 0.12);
  border-radius: 999px;
  background: var(--surface);
  box-shadow: 0 10px 30px rgba(35, 65, 55, 0.1);
  color: var(--green);
  font-family: Georgia, serif;
  font-size: 14px;
  font-style: italic;
}

.tag-one { top: 52px; left: 2%; }
.tag-two { top: 180px; right: 0; }
.tag-three { bottom: 70px; left: 8%; }
.tag-four { right: 4%; bottom: 10px; background: var(--orange); color: #432619; }

@keyframes float {
  50% { transform: translateY(-10px); }
}

.chapter-nav {
  position: relative;
  z-index: 5;
  display: grid;
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto 30px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(255, 253, 248, 0.88);
  box-shadow: var(--shadow);
  grid-template-columns: repeat(6, 1fr);
  backdrop-filter: blur(16px);
}

.chapter-nav a {
  display: flex;
  padding: 18px 16px;
  border-right: 1px solid var(--line);
  color: var(--text);
  font-size: 13px;
  font-weight: 800;
  text-decoration: none;
  gap: 8px;
  align-items: center;
  justify-content: center;
}

.chapter-nav a:last-child {
  border-right: 0;
}

.chapter-nav span {
  color: var(--orange);
  font-family: Georgia, serif;
  font-size: 12px;
}

.lesson-section {
  position: relative;
  width: min(1040px, calc(100% - 48px));
  margin: 0 auto;
  padding: 100px 0;
  border-bottom: 1px solid var(--line);
  scroll-margin-top: 70px;
}

.section-number {
  position: absolute;
  top: 88px;
  right: 0;
  color: rgba(10, 107, 88, 0.09);
  font-family: Georgia, serif;
  font-size: 100px;
  line-height: 1;
}

.section-heading {
  position: relative;
  z-index: 1;
  max-width: 700px;
  margin-bottom: 42px;
}

.section-heading h2 {
  margin: 0 0 10px;
  font-family: Georgia, "Songti SC", serif;
  font-size: clamp(38px, 5vw, 62px);
  font-weight: 500;
  letter-spacing: -0.04em;
  line-height: 1.1;
}

.section-heading > span {
  color: var(--muted);
}

.warmup-grid,
.output-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 22px;
}

.guide-card,
.question-card,
.output-task {
  padding: 34px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--surface);
}

.card-kicker,
.task-label {
  color: var(--orange);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.14em;
}

.guide-card h3,
.output-task h3 {
  margin: 8px 0 22px;
  font-family: Georgia, "Songti SC", serif;
  font-size: 28px;
  line-height: 1.3;
}

.route-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.route-list li {
  display: flex;
  padding: 15px 0;
  border-top: 1px solid var(--line);
  gap: 15px;
}

.route-list li > span {
  color: var(--orange);
  font-family: Georgia, serif;
  font-size: 18px;
}

.route-list p {
  margin: 3px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.big-question {
  margin: 28px 0 50px;
  font-family: Georgia, "Songti SC", serif;
  font-size: 26px;
  line-height: 1.55;
}

label {
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
}

textarea {
  width: 100%;
  margin-top: 10px;
  padding: 16px;
  resize: vertical;
  border: 1px solid var(--line);
  border-radius: 14px;
  outline: 0;
  background: var(--bg);
  color: var(--text);
}

textarea:focus,
.quiz-input:focus {
  border-color: var(--green);
  box-shadow: 0 0 0 3px rgba(10, 107, 88, 0.1);
}

.video-card {
  display: grid;
  overflow: hidden;
  margin-top: 22px;
  border-radius: 24px;
  background: var(--green);
  color: white;
  grid-template-columns: minmax(0, 1.55fr) minmax(280px, 0.75fr);
}

.video-frame {
  min-height: 390px;
  background: #091c19;
}

.video-frame iframe,
.video-frame video {
  width: 100%;
  height: 100%;
  border: 0;
}

.video-frame video {
  display: block;
  object-fit: contain;
  background: #111;
}

.video-copy {
  padding: 34px;
}

.video-copy h3 {
  margin: 0;
  font-family: Georgia, serif;
  font-size: 34px;
}

.video-copy blockquote {
  margin: 28px 0;
  padding-left: 16px;
  border-left: 3px solid var(--lime);
  font-family: Georgia, serif;
  font-size: 20px;
  font-style: italic;
}

.answer-toggle,
#resetQuiz,
#completeLesson {
  padding: 10px 16px;
  border: 1px solid currentColor;
  border-radius: 999px;
  background: transparent;
  color: inherit;
  cursor: pointer;
  font-size: 12px;
  font-weight: 900;
}

.hidden-answer {
  display: none;
}

.hidden-answer.visible {
  display: block;
}

.video-copy .hidden-answer {
  color: var(--green-2);
  font-size: 13px;
}

.section-note {
  display: flex;
  margin-bottom: 20px;
  padding: 14px 18px;
  border-radius: 12px;
  background: var(--surface-2);
  color: var(--muted);
  gap: 14px;
  font-size: 13px;
}

.section-note b {
  color: var(--green);
  white-space: nowrap;
}

.transcript-list {
  border-top: 1px solid var(--line);
}

.transcript-item {
  display: grid;
  padding: 30px 0;
  border-bottom: 1px solid var(--line);
  grid-template-columns: 64px minmax(0, 1fr) minmax(0, 1fr);
  gap: 28px;
}

.para-label {
  color: var(--orange);
  font-family: Georgia, serif;
  font-size: 13px;
  font-style: italic;
}

.transcript-en {
  font-family: Georgia, serif;
  font-size: 20px;
  line-height: 1.65;
}

.transcript-zh {
  color: #40564f;
  font-size: 16px;
}

.inline-audio {
  display: flex;
  margin-top: 18px;
  grid-column: 2 / -1;
  gap: 12px;
  align-items: center;
}

.play-segment {
  display: grid;
  width: 42px;
  height: 42px;
  flex: 0 0 auto;
  place-items: center;
  border: 0;
  border-radius: 50%;
  background: var(--green);
  color: white;
  cursor: pointer;
}

.audio-track {
  width: 100%;
  height: 36px;
}

.phrase-grid {
  display: grid;
  margin-bottom: 50px;
  gap: 12px;
}

.phrase-card {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  transition: border-color 180ms ease, box-shadow 180ms ease;
}

.phrase-card[open] {
  border-color: rgba(10, 107, 88, 0.45);
  box-shadow: 0 18px 45px rgba(35, 65, 55, 0.08);
}

.phrase-card summary {
  display: grid;
  min-height: 82px;
  padding: 18px 22px;
  cursor: pointer;
  list-style: none;
  grid-template-columns: 44px 1fr 28px;
  gap: 14px;
  align-items: center;
}

.phrase-card summary::-webkit-details-marker {
  display: none;
}

.phrase-card summary:focus-visible {
  outline: 3px solid rgba(10, 107, 88, 0.2);
  outline-offset: -3px;
}

.phrase-index {
  color: var(--orange);
  font-family: Georgia, serif;
  font-size: 14px;
  font-style: italic;
}

.phrase-title strong,
.phrase-title small {
  display: block;
}

.phrase-title strong {
  margin: 0;
  color: var(--green);
  font-family: Georgia, serif;
  font-size: 25px;
  line-height: 1.25;
}

.phrase-title small {
  margin-top: 3px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
}

.phrase-toggle {
  position: relative;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--surface-2);
}

.phrase-toggle::before,
.phrase-toggle::after {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 11px;
  height: 1.5px;
  border-radius: 3px;
  background: var(--green);
  content: "";
  transform: translate(-50%, -50%);
  transition: transform 180ms ease;
}

.phrase-toggle::after {
  transform: translate(-50%, -50%) rotate(90deg);
}

.phrase-card[open] .phrase-toggle::after {
  transform: translate(-50%, -50%) rotate(0deg);
}

.phrase-detail {
  display: grid;
  padding: 0 22px 28px 80px;
  border-top: 1px solid var(--line);
  grid-template-columns: minmax(220px, 0.7fr) minmax(0, 1.3fr);
  gap: 0 34px;
}

.source-context {
  padding: 26px 0;
  grid-column: 1 / -1;
}

.source-context > span {
  color: var(--orange);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.14em;
}

.source-context blockquote {
  margin: 10px 0 0;
  padding: 15px 18px;
  border-left: 3px solid var(--lime);
  border-radius: 0 12px 12px 0;
  background: var(--bg);
  color: var(--text);
  font-family: Georgia, serif;
  font-size: 18px;
  font-style: italic;
  line-height: 1.6;
}

.meaning-block,
.example-block {
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.meaning-block h4,
.example-block h4 {
  margin: 0 0 16px;
  color: var(--orange);
  font-size: 13px;
  letter-spacing: 0.08em;
}

.meaning-block ul {
  margin: 0;
  padding-left: 19px;
}

.meaning-block li {
  margin-bottom: 12px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.75;
}

.phrase-pattern {
  display: flex;
  margin: 20px 0 0;
  padding: 12px 14px;
  border-radius: 10px;
  background: var(--surface-2);
  gap: 10px;
  align-items: baseline;
  flex-wrap: wrap;
}

.phrase-pattern span {
  color: var(--orange);
  font-size: 11px;
  font-weight: 900;
}

.phrase-pattern code {
  color: var(--text);
  font-family: Georgia, serif;
  font-size: 14px;
}

.phrase-examples {
  display: grid;
  gap: 11px;
}

.phrase-example {
  display: grid;
  padding: 13px 14px;
  border-radius: 11px;
  background: var(--bg);
  grid-template-columns: 30px 1fr;
  gap: 10px;
}

.phrase-example > span {
  color: var(--orange);
  font-family: Georgia, serif;
  font-size: 12px;
}

.phrase-example p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
}

.phrase-example p[lang="en"] {
  margin-top: 4px;
  color: var(--text);
  font-family: Georgia, serif;
  font-size: 15px;
}

.phrase-example mark {
  padding: 1px 3px;
  border-radius: 4px;
  background: rgba(243, 154, 96, 0.22);
  color: var(--green);
  font-weight: 700;
}

.vocab-panel {
  display: grid;
  padding: 42px;
  border-radius: 24px;
  background: var(--green);
  color: white;
  grid-template-columns: minmax(220px, 0.58fr) minmax(0, 1.42fr);
  gap: 44px;
  align-items: start;
}

.vocab-intro {
  position: sticky;
  top: 110px;
}

.vocab-intro h3 {
  margin: 0;
  font-family: Georgia, "Songti SC", serif;
  font-size: 38px;
  line-height: 1.25;
}

.vocab-intro > p:last-child {
  color: rgba(255, 255, 255, 0.72);
  font-size: 13px;
}

.vocab-item {
  border-bottom: 1px solid rgba(255, 255, 255, 0.18);
}

.vocab-button {
  display: grid;
  width: 100%;
  min-height: 70px;
  padding: 14px 0;
  color: white;
  cursor: pointer;
  list-style: none;
  text-align: left;
  grid-template-columns: 1fr auto;
  gap: 14px;
  align-items: center;
}

.vocab-button::-webkit-details-marker {
  display: none;
}

.vocab-heading {
  display: flex;
  gap: 8px;
  align-items: baseline;
  flex-wrap: wrap;
}

.vocab-heading strong {
  font-family: Georgia, serif;
  font-size: 24px;
}

.vocab-heading small {
  color: rgba(255, 255, 255, 0.68);
  font-size: 12px;
}

.vocab-pos {
  padding: 2px 7px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 999px;
  color: var(--lime);
  font-size: 9px;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.vocab-toggle {
  position: relative;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
}

.vocab-toggle::before,
.vocab-toggle::after {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 10px;
  height: 1.5px;
  border-radius: 2px;
  background: white;
  content: "";
  transform: translate(-50%, -50%);
  transition: transform 180ms ease;
}

.vocab-toggle::after {
  transform: translate(-50%, -50%) rotate(90deg);
}

.vocab-item[open] .vocab-toggle::after {
  transform: translate(-50%, -50%) rotate(0);
}

.vocab-detail {
  padding: 0 0 24px;
}

.vocab-source {
  padding: 15px 17px;
  border-left: 3px solid var(--lime);
  border-radius: 0 10px 10px 0;
  background: rgba(255, 255, 255, 0.08);
}

.vocab-source span,
.vocab-meta span {
  color: var(--lime);
  font-size: 10px;
  font-weight: 900;
  letter-spacing: 0.12em;
}

.vocab-source p {
  margin: 5px 0 0;
  font-family: Georgia, serif;
  font-size: 16px;
  font-style: italic;
  line-height: 1.55;
}

.vocab-explanation {
  display: grid;
  padding: 20px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.14);
  grid-template-columns: 1fr 1fr;
  gap: 22px;
}

.vocab-explanation h5,
.vocab-usage h5 {
  margin: 0 0 8px;
  color: var(--orange);
  font-size: 12px;
}

.vocab-explanation p,
.vocab-meta p {
  margin: 0;
  color: rgba(255, 255, 255, 0.76);
  font-size: 12px;
  line-height: 1.72;
}

.vocab-meta {
  display: grid;
  padding: 18px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.14);
  grid-template-columns: 1fr 1fr;
  gap: 22px;
}

.vocab-meta p {
  margin-top: 7px;
}

.vocab-meta code {
  display: inline-block;
  margin: 0 5px 5px 0;
  padding: 3px 7px;
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.1);
  color: white;
  font-family: Georgia, serif;
  font-size: 11px;
}

.vocab-usage {
  padding-top: 19px;
}

.vocab-usage-row {
  display: grid;
  padding: 10px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  grid-template-columns: 27px 1fr;
  gap: 8px;
}

.vocab-usage-row > span {
  color: var(--orange);
  font-family: Georgia, serif;
  font-size: 11px;
}

.vocab-usage-row p {
  margin: 0;
  color: rgba(255, 255, 255, 0.68);
  font-size: 12px;
}

.vocab-usage-row p[lang="en"] {
  margin-bottom: 3px;
  color: white;
  font-family: Georgia, serif;
  font-size: 15px;
}

.vocab-usage-row mark {
  padding: 1px 3px;
  border-radius: 4px;
  background: rgba(214, 240, 111, 0.2);
  color: var(--lime);
  font-weight: 700;
}

.listening-section {
  width: min(1120px, calc(100% - 48px));
}

.listening-guide {
  overflow: hidden;
  margin-bottom: 34px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--surface);
}

.listening-guide summary {
  display: flex;
  min-height: 64px;
  padding: 15px 22px;
  cursor: pointer;
  list-style: none;
  color: var(--green);
  font-weight: 900;
  justify-content: space-between;
  align-items: center;
}

.listening-guide summary::-webkit-details-marker {
  display: none;
}

.listening-guide summary i {
  position: relative;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--surface-2);
}

.listening-guide summary i::before,
.listening-guide summary i::after {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 10px;
  height: 1.5px;
  background: var(--green);
  content: "";
  transform: translate(-50%, -50%);
}

.listening-guide summary i::after {
  transform: translate(-50%, -50%) rotate(90deg);
}

.listening-guide[open] summary i::after {
  transform: translate(-50%, -50%);
}

.listening-guide-body {
  padding: 0 22px 25px;
  border-top: 1px solid var(--line);
}

.guide-alert {
  margin: 22px 0;
  color: var(--red);
  font-size: 14px;
  font-weight: 900;
}

.listening-steps {
  display: grid;
  gap: 12px;
}

.listening-steps > div {
  display: grid;
  padding: 16px 18px;
  border-radius: 12px;
  background: var(--bg);
  grid-template-columns: 78px 1fr;
  gap: 14px;
}

.listening-steps span,
.stage-title span,
.quiz-heading span {
  color: var(--orange);
  font-family: Georgia, serif;
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.08em;
}

.listening-steps p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.listening-steps b {
  color: var(--text);
}

.listening-tips {
  margin-top: 23px;
  padding-top: 21px;
  border-top: 1px solid var(--line);
}

.listening-tips strong {
  color: var(--green);
}

.listening-tips ul {
  margin: 12px 0 0;
  padding-left: 20px;
  color: var(--muted);
  font-size: 13px;
}

.listening-tips li {
  margin: 8px 0;
}

.listening-stage,
.audio-listening-stage {
  margin-bottom: 38px;
}

.stage-title {
  display: flex;
  margin-bottom: 14px;
  padding: 0 4px;
  justify-content: space-between;
  align-items: end;
  gap: 20px;
}

.stage-title h3,
.quiz-heading h3 {
  margin: 2px 0 0;
  font-family: Georgia, "Songti SC", serif;
  font-size: 28px;
  font-weight: 500;
}

.stage-title > p,
.quiz-heading p {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
}

.listening-video {
  overflow: hidden;
  border-radius: 22px;
  background: #0b201c;
}

.listening-video-frame {
  position: relative;
  min-height: 470px;
  background: #111;
}

.listening-video-frame iframe,
.listening-video-frame video {
  width: 100%;
  height: 100%;
  border: 0;
}

.listening-video-frame video {
  display: block;
  object-fit: contain;
  background: #111;
}

.focus-video-overlay {
  position: absolute;
  top: 8%;
  right: 3.5%;
  z-index: 2;
  display: flex;
  width: min(280px, 34%);
  max-height: 84%;
  padding: 24px 22px;
  border-radius: 24px;
  background: linear-gradient(90deg, rgba(3, 10, 9, 0.58), rgba(3, 10, 9, 0.9));
  color: white;
  flex-direction: column;
  gap: 14px;
  pointer-events: none;
  box-shadow: -18px 0 46px rgba(0, 0, 0, 0.28);
}

.focus-video-overlay::after {
  position: absolute;
  right: -18px;
  bottom: 24px;
  color: rgba(255, 255, 255, 0.08);
  content: "@lingolab";
  font-size: clamp(34px, 5vw, 76px);
  font-weight: 900;
  letter-spacing: -0.08em;
  writing-mode: vertical-rl;
}

.focus-video-overlay > p {
  position: relative;
  z-index: 1;
  margin: 0;
  color: var(--orange);
  font-size: 10px;
  font-weight: 900;
  letter-spacing: 0.14em;
}

.focus-cue-list {
  position: relative;
  z-index: 1;
  display: grid;
  overflow: visible;
  padding-left: 6px;
  gap: 10px;
}

.focus-cue {
  display: none;
  opacity: 0.44;
  padding: 8px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.14);
  transform: translateX(0);
  transition:
    opacity 180ms ease,
    transform 180ms ease,
    color 180ms ease;
}

.focus-cue.visible {
  display: block;
}

.focus-cue.active {
  opacity: 1;
  transform: translateX(0);
}

.focus-cue strong,
.focus-cue span,
.focus-cue small {
  display: block;
}

.focus-cue strong {
  color: rgba(255, 255, 255, 0.78);
  font-family: Georgia, serif;
  font-size: 21px;
  line-height: 1.15;
  overflow-wrap: anywhere;
}

.focus-cue.active strong {
  color: #61e6c1;
  text-shadow: 0 0 18px rgba(97, 230, 193, 0.3);
}

.focus-cue span {
  margin-top: 3px;
  color: rgba(255, 255, 255, 0.68);
  font-size: 12px;
}

.focus-cue.active span {
  color: rgba(188, 255, 236, 0.9);
}

.focus-cue small {
  margin-top: 2px;
  color: rgba(255, 255, 255, 0.42);
  font-size: 11px;
}

.focus-cue.active small {
  color: rgba(255, 255, 255, 0.72);
}

#focusCueStatus {
  position: relative;
  z-index: 1;
  margin-top: auto;
  color: rgba(255, 255, 255, 0.46);
  font-size: 10px;
}

.full-audio-player {
  display: grid;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--surface);
  grid-template-columns: 60px minmax(160px, 0.45fr) minmax(280px, 1fr) auto;
  gap: 18px;
  align-items: center;
}

.audio-symbol {
  display: grid;
  width: 54px;
  height: 54px;
  place-items: center;
  border-radius: 50%;
  background: var(--green);
  color: white;
  font-size: 8px;
  font-weight: 900;
  letter-spacing: 0.08em;
}

.full-audio-player > div:nth-child(2) strong,
.full-audio-player > div:nth-child(2) span {
  display: block;
}

.full-audio-player > div:nth-child(2) strong {
  font-family: Georgia, serif;
}

.full-audio-player > div:nth-child(2) span {
  margin-top: 3px;
  color: var(--muted);
  font-size: 11px;
}

.full-audio-player audio {
  width: 100%;
}

.listening-speed {
  display: flex;
  gap: 5px;
}

.listening-speed button {
  padding: 6px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 10px;
}

.listening-speed button.active {
  border-color: var(--green);
  background: var(--green);
  color: white;
}

.quiz-heading {
  margin-top: 65px;
  margin-bottom: 16px;
  padding-top: 34px;
  border-top: 1px solid var(--line);
}

.listen-toolbar {
  display: flex;
  margin-bottom: 16px;
  padding: 16px 22px;
  border-radius: 14px;
  background: var(--surface-2);
  justify-content: space-between;
  align-items: center;
}

.listen-toolbar span {
  display: block;
  color: var(--muted);
  font-size: 11px;
}

.listen-toolbar strong {
  font-family: Georgia, serif;
  font-size: 23px;
}

.listen-toolbar button {
  color: var(--green);
}

.quiz-list {
  display: grid;
  gap: 14px;
}

.quiz-card {
  display: grid;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--surface);
  grid-template-columns: 54px 1fr;
  gap: 20px;
}

.quiz-number {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 50%;
  background: var(--surface-2);
  color: var(--orange);
  font-family: Georgia, serif;
}

.quiz-card.correct {
  border-color: var(--green);
}

.quiz-card.incorrect {
  border-color: var(--red);
}

.quiz-sentence {
  margin: 0 0 18px;
  font-family: Georgia, serif;
  font-size: 20px;
}

.quiz-input {
  width: min(300px, 100%);
  padding: 9px 12px;
  border: 0;
  border-bottom: 2px solid var(--green-2);
  outline: 0;
  background: transparent;
  color: var(--text);
  text-align: center;
}

.quiz-actions {
  display: flex;
  margin-top: 16px;
  gap: 10px;
}

.quiz-actions button {
  padding: 8px 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--bg);
  color: var(--text);
  cursor: pointer;
  font-size: 12px;
  font-weight: 800;
}

.quiz-feedback {
  min-height: 20px;
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 12px;
}

.speaking-guide {
  overflow: hidden;
  margin-bottom: 24px;
  border: 1px solid rgba(220, 216, 205, 0.95);
  border-radius: 24px;
  background: rgba(255, 253, 248, 0.72);
}

.speaking-guide summary {
  display: flex;
  padding: 18px 22px;
  cursor: pointer;
  list-style: none;
  justify-content: space-between;
  align-items: center;
  color: var(--muted);
  font-weight: 900;
}

.speaking-guide summary::-webkit-details-marker {
  display: none;
}

.speaking-guide summary i {
  position: relative;
  width: 18px;
  height: 18px;
}

.speaking-guide summary i::before,
.speaking-guide summary i::after {
  position: absolute;
  top: 8px;
  left: 2px;
  width: 14px;
  height: 2px;
  border-radius: 99px;
  background: var(--muted);
  content: "";
}

.speaking-guide summary i::after {
  transform: rotate(90deg);
}

.speaking-guide[open] summary i::after {
  display: none;
}

.speaking-guide-body {
  padding: 4px 26px 28px;
  border-top: 1px solid var(--line);
}

.speaking-steps {
  display: grid;
  margin: 18px 0;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.speaking-steps > div {
  padding: 18px;
  border-radius: 16px;
  background: var(--bg);
}

.speaking-steps span {
  display: block;
  margin-bottom: 8px;
  color: var(--orange);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.12em;
}

.speaking-steps p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.speaking-steps b {
  color: var(--text);
}

.pronunciation-notes {
  padding: 24px;
  border-radius: 18px;
  background: rgba(239, 234, 221, 0.55);
}

.pronunciation-notes h3 {
  margin: 0 0 14px;
  color: #8a642e;
  font-size: 18px;
  text-decoration: underline;
  text-underline-offset: 6px;
}

.pronunciation-notes ul {
  padding: 0;
  margin: 0;
  list-style: none;
}

.pronunciation-notes li {
  display: grid;
  margin: 16px 0;
  grid-template-columns: 34px 1fr;
  gap: 12px;
  color: var(--text);
}

.pronunciation-notes em {
  color: var(--green);
  font-style: normal;
  font-weight: 850;
}

.pronunciation-notes > p {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.legend-line {
  display: inline-block;
  width: 30px;
  height: 4px;
  margin-top: 12px;
  border-radius: 99px;
}

.link-line { background: var(--green); }
.weak-line { background: #b8b8b8; }
.reduction-line { background: #a8a8a8; }
.stress-line { background: var(--orange); }

.pronunciation-legend {
  display: flex;
  margin-bottom: 18px;
  gap: 20px;
  flex-wrap: wrap;
}

.pronunciation-legend span {
  display: flex;
  color: var(--muted);
  font-size: 12px;
  gap: 7px;
  align-items: center;
}

.pronunciation-legend i {
  display: inline-block;
  width: 22px;
  height: 3px;
  background: var(--green);
}

.pronunciation-legend .weak-mark { background: #b8b8b8; }
.pronunciation-legend .reduction-mark { background: #a8a8a8; }
.pronunciation-legend .stress-mark { background: var(--orange); }
.pronunciation-legend .pause-mark { width: 2px; height: 16px; background: var(--muted); }

.shadow-card {
  padding: 38px;
  border-radius: 24px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.shadow-overview {
  margin-bottom: 34px;
}

.shadow-controls {
  display: flex;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
  justify-content: space-between;
  align-items: center;
}

.shadow-controls > span {
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.speed-buttons {
  display: flex;
  gap: 7px;
}

.speed-buttons button {
  padding: 7px 11px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 11px;
}

.speed-buttons button.active {
  border-color: var(--green);
  background: var(--green);
  color: white;
}

.shadow-overview-copy {
  display: flex;
  padding: 26px 0;
  gap: 30px;
  justify-content: space-between;
  align-items: flex-end;
}

.shadow-overview-copy span {
  color: var(--orange);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0.13em;
}

.shadow-overview-copy h3 {
  margin: 6px 0 0;
  font-family: Georgia, serif;
  font-size: clamp(28px, 4vw, 48px);
  line-height: 1.08;
}

.shadow-overview-copy p {
  max-width: 420px;
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.shadow-lines {
  padding: 30px 0;
}

.shadow-lines p {
  margin: 13px 0;
  font-family: Georgia, serif;
  font-size: clamp(21px, 3vw, 32px);
  line-height: 1.5;
}

.shadow-lines strong {
  color: var(--green);
  font-weight: 500;
  text-decoration: underline;
  text-decoration-color: var(--green-2);
  text-decoration-thickness: 4px;
  text-underline-offset: 5px;
}

#shadowAudio {
  width: 100%;
}

.shadow-steps {
  display: grid;
  margin-top: 26px;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.shadow-steps div {
  padding: 16px;
  border-radius: 12px;
  background: var(--bg);
}

.shadow-steps span {
  color: var(--orange);
  font-family: Georgia, serif;
}

.shadow-steps p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 12px;
}

.shadow-practice-list {
  display: grid;
  gap: 22px;
}

.shadow-practice-card {
  overflow: hidden;
  padding: 0 0 28px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--surface);
  box-shadow: 0 16px 40px rgba(35, 65, 55, 0.08);
}

.shadow-practice-label {
  display: flex;
  padding: 12px 18px;
  background: var(--surface-2);
  gap: 16px;
  align-items: center;
}

.shadow-practice-label span {
  min-width: 46px;
  color: var(--text);
  font-family: Georgia, serif;
  font-size: 18px;
  font-style: italic;
  font-weight: 900;
}

.shadow-practice-label small {
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.shadow-practice-text {
  position: relative;
  padding: 54px 58px 38px;
  color: #111;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(22px, 3vw, 40px);
  line-height: 1.62;
}

.shadow-practice-text::after {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) rotate(-8deg);
  color: rgba(10, 107, 88, 0.055);
  content: "@lingolab";
  font-family: Inter, "PingFang SC", sans-serif;
  font-size: clamp(42px, 8vw, 108px);
  font-weight: 900;
  letter-spacing: -0.06em;
  pointer-events: none;
}

.shadow-practice-text .link {
  color: #78b8a7;
  text-decoration: underline;
  text-decoration-color: #9bd1c3;
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.12em;
}

.shadow-practice-text .weak {
  color: #a7a7a7;
}

.shadow-practice-text .reduction {
  color: #9b9b9b;
  text-decoration: line-through;
  text-decoration-color: #8d8d8d;
  text-decoration-thickness: 0.06em;
}

.shadow-practice-text .stress {
  color: #bd5f4d;
}

.shadow-practice-text .stress .link {
  color: #78b8a7;
}

.shadow-practice-text .pause {
  display: inline-block;
  margin: 0 0.18em;
  color: #c7bca5;
  font-family: Inter, "PingFang SC", sans-serif;
  font-size: 0.72em;
  font-weight: 700;
  transform: translateY(-0.06em);
}

.shadow-practice-audio-row {
  margin: 0 58px;
}

.output-guide {
  overflow: hidden;
  margin-bottom: 26px;
  border: 1px solid rgba(220, 216, 205, 0.95);
  border-radius: 22px;
  background: rgba(255, 253, 248, 0.74);
}

.output-guide summary {
  display: flex;
  padding: 18px 22px;
  cursor: pointer;
  list-style: none;
  justify-content: space-between;
  align-items: center;
  color: var(--muted);
  font-weight: 900;
}

.output-guide summary::-webkit-details-marker {
  display: none;
}

.output-guide summary i {
  position: relative;
  width: 18px;
  height: 18px;
}

.output-guide summary i::before,
.output-guide summary i::after {
  position: absolute;
  top: 8px;
  left: 2px;
  width: 14px;
  height: 2px;
  border-radius: 99px;
  background: var(--muted);
  content: "";
}

.output-guide summary i::after {
  transform: rotate(90deg);
}

.output-guide[open] summary i::after {
  display: none;
}

.output-guide-body {
  padding: 4px 26px 28px;
  border-top: 1px solid var(--line);
}

.output-steps {
  display: grid;
  margin: 18px 0;
  gap: 12px;
}

.output-steps div {
  padding: 14px 16px;
  border-left: 3px solid var(--green);
  border-radius: 0 12px 12px 0;
  background: var(--bg);
  color: var(--text);
}

.output-tips {
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.output-tips strong {
  color: var(--red);
}

.output-tips ol {
  padding-left: 24px;
  margin: 14px 0 0;
}

.output-tips li {
  margin: 9px 0;
}

.output-block {
  margin-top: 28px;
}

.output-block-title {
  display: flex;
  min-height: 46px;
  padding: 10px 16px;
  border-radius: 10px;
  background: var(--surface-2);
  gap: 12px;
  align-items: center;
  color: var(--text);
}

.output-block-title span {
  font-family: Georgia, serif;
  font-size: 18px;
  font-style: italic;
  font-weight: 900;
}

.output-block-title strong {
  font-size: 18px;
}

.output-video-frame {
  overflow: hidden;
  margin-top: 34px;
  border-radius: 18px;
  background: #111;
  aspect-ratio: 16 / 9;
}

.output-video-frame iframe,
.output-video-frame video {
  width: 100%;
  height: 100%;
  border: 0;
}

.output-video-frame video {
  display: block;
  object-fit: contain;
  background: #111;
}

.output-full-audio {
  width: 100%;
  margin-top: 18px;
}

.practice-tables {
  display: grid;
  margin-top: 28px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 90px;
  align-items: start;
}

.practice-tables table {
  width: 100%;
  border-collapse: collapse;
  background: var(--surface);
  font-size: 15px;
}

.practice-tables th,
.practice-tables td {
  padding: 13px 14px;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.practice-tables th {
  width: 42%;
  font-weight: 900;
}

.tag {
  display: inline-block;
  padding: 1px 5px;
  border-radius: 4px;
  background: var(--surface-2);
  color: var(--muted);
  font-weight: 800;
}

.tag.phrase {
  background: #eeeeea;
}

.tag.noun {
  background: rgba(10, 107, 88, 0.12);
  color: var(--green);
}

.tag.adj,
.tag.adv {
  background: rgba(243, 154, 96, 0.16);
  color: #9b5c28;
}

.sentence-drills {
  display: grid;
  margin-top: 56px;
  gap: 22px 26px;
  grid-template-columns: 110px minmax(0, 1fr);
}

.drill-level {
  width: max-content;
  height: max-content;
  padding: 0 4px;
  font-family: Georgia, serif;
  font-size: 20px;
  font-style: italic;
  font-weight: 900;
  text-decoration: underline;
  text-decoration-thickness: 8px;
  text-decoration-skip-ink: none;
  text-underline-offset: -4px;
}

.drill-level.easy {
  text-decoration-color: rgba(10, 107, 88, 0.18);
}

.drill-level.medium {
  text-decoration-color: rgba(214, 240, 111, 0.4);
}

.drill-level.hard {
  text-decoration-color: rgba(213, 82, 63, 0.18);
}

.drill-list {
  display: grid;
  padding-left: 18px;
  border-left: 2px solid var(--line);
  gap: 12px;
}

.drill-list details {
  padding: 0 0 12px;
  border-bottom: 1px solid var(--line);
}

.drill-list summary {
  cursor: pointer;
  color: var(--text);
  font-weight: 800;
}

.drill-list p {
  margin: 10px 0 0 22px;
  color: var(--text);
  font-size: 18px;
}

.drill-list mark {
  padding: 1px 4px;
  border-radius: 4px;
  background: var(--surface-2);
  color: inherit;
}

.completion-card {
  display: grid;
  margin-top: 24px;
  padding: 34px;
  border-radius: 22px;
  background: var(--green);
  color: white;
  grid-template-columns: 1fr 1fr auto;
  gap: 30px;
  align-items: center;
}

.completion-card h3 {
  margin: 0;
  font-family: Georgia, "Songti SC", serif;
  font-size: 25px;
}

.check-list {
  display: grid;
  gap: 6px;
}

.check-list label {
  color: var(--green-2);
  cursor: pointer;
}

.check-list input {
  accent-color: var(--lime);
}

#completeLesson {
  border-color: var(--lime);
  background: var(--lime);
  color: var(--green);
}

#completionMessage {
  margin: 0;
  color: var(--lime);
  font-size: 12px;
  grid-column: 1 / -1;
}

footer {
  display: flex;
  width: min(1120px, calc(100% - 48px));
  margin: 0 auto;
  padding: 50px 0 70px;
  color: var(--muted);
  font-size: 12px;
  justify-content: space-between;
  align-items: center;
  gap: 30px;
}

footer a {
  color: var(--green);
  font-weight: 800;
  text-decoration: none;
}

body.dark {
  color-scheme: dark;
  --bg: #10231f;
  --surface: #17312b;
  --surface-2: #203d36;
  --text: #eef4e8;
  --muted: #a7b8b1;
  --line: #315048;
  --green: #74d5b6;
  --green-2: #2c5a4d;
  --lime: #d6f06f;
  --orange: #f1a06d;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.22);
}

body.dark .topbar {
  background: rgba(16, 35, 31, 0.88);
}

body.dark .play-segment,
body.dark .primary-button {
  background: #08705c;
}

body.dark .accent-task {
  color: #35231a;
}

body.dark .shadow-practice-text {
  color: #eef4e8;
}

body.dark .pronunciation-notes {
  background: rgba(32, 61, 54, 0.7);
}

@media (max-width: 900px) {
  .hero {
    grid-template-columns: 1fr;
  }

  .hero-art {
    min-height: 480px;
  }

  .chapter-nav {
    overflow-x: auto;
    grid-template-columns: repeat(6, minmax(130px, 1fr));
  }

  .video-card,
  .vocab-panel,
  .listening-video,
  .completion-card {
    grid-template-columns: 1fr;
  }

  .listening-video-frame {
    min-height: 0;
    aspect-ratio: 16 / 9;
  }

  .practice-tables {
    grid-template-columns: 1fr;
    gap: 22px;
  }

  .focus-video-overlay {
    top: auto;
    right: 18px;
    bottom: 18px;
    width: min(420px, calc(100% - 36px));
    max-height: 58%;
    padding: 16px;
  }

  .focus-cue-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 6px 14px;
  }

  .focus-cue {
    padding: 6px 0;
  }

  .focus-cue strong {
    font-size: 16px;
  }

  .full-audio-player {
    grid-template-columns: 54px 1fr;
  }

  .full-audio-player audio,
  .listening-speed {
    grid-column: 1 / -1;
  }

  .speaking-steps {
    grid-template-columns: 1fr;
  }

  .shadow-overview-copy {
    align-items: flex-start;
    flex-direction: column;
    gap: 14px;
  }

  .vocab-intro {
    position: static;
  }

  .video-frame {
    aspect-ratio: 16 / 9;
    min-height: 0;
  }

  .transcript-item {
    grid-template-columns: 50px 1fr;
  }

  .transcript-zh {
    grid-column: 2;
  }

  .shadow-steps {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 660px) {
  .topbar {
    height: 66px;
    padding-inline: 18px;
  }

  .progress-track {
    top: 64px;
  }

  .level-pill {
    display: none;
  }

  .hero {
    min-height: auto;
    padding: 65px 24px 40px;
  }

  .hero h1 {
    font-size: 48px;
  }

  .hero-meta {
    gap: 14px;
  }

  .hero-art {
    min-height: 420px;
    transform: scale(.88);
  }

  .chapter-nav,
  .lesson-section,
  footer {
    width: calc(100% - 32px);
  }

  .lesson-section {
    padding: 75px 0;
  }

  .section-number {
    top: 70px;
    font-size: 74px;
  }

  .warmup-grid,
  .output-grid {
    grid-template-columns: 1fr;
  }

  .phrase-card summary {
    min-height: 72px;
    padding: 15px;
    grid-template-columns: 34px 1fr 28px;
    gap: 9px;
  }

  .phrase-title strong {
    font-size: 21px;
  }

  .phrase-detail {
    padding: 0 15px 20px;
    grid-template-columns: 1fr;
  }

  .source-context {
    padding: 20px 0;
  }

  .meaning-block,
  .example-block {
    padding-top: 20px;
  }

  .example-block {
    margin-top: 22px;
  }

  .vocab-explanation,
  .vocab-meta {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .vocab-heading {
    align-items: flex-start;
    flex-direction: column;
    gap: 3px;
  }

  .vocab-heading small {
    line-height: 1.5;
  }

  .guide-card,
  .question-card,
  .output-task,
  .shadow-card,
  .vocab-panel {
    padding: 24px;
  }

  .transcript-item {
    padding: 24px 0;
    gap: 14px;
  }

  .transcript-en {
    font-size: 18px;
  }

  .speaking-guide-body {
    padding: 2px 18px 22px;
  }

  .pronunciation-notes {
    padding: 18px;
  }

  .pronunciation-notes li {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .output-guide-body {
    padding: 2px 18px 22px;
  }

  .output-block-title {
    align-items: flex-start;
    flex-direction: column;
    gap: 2px;
  }

  .practice-tables th,
  .practice-tables td {
    padding: 10px;
    font-size: 13px;
  }

  .sentence-drills {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .drill-list {
    padding-left: 14px;
  }

  .drill-list p {
    margin-left: 0;
    font-size: 16px;
  }

  .legend-line {
    margin-top: 0;
  }

  .shadow-practice-label {
    align-items: flex-start;
    flex-direction: column;
    gap: 4px;
  }

  .shadow-practice-text {
    padding: 34px 22px 28px;
    font-size: clamp(22px, 7vw, 30px);
    line-height: 1.55;
  }

  .shadow-practice-audio-row {
    margin: 0 22px;
  }

  .quiz-card {
    padding: 20px;
    grid-template-columns: 1fr;
  }

  .listening-steps > div {
    grid-template-columns: 1fr;
    gap: 5px;
  }

  .stage-title {
    align-items: flex-start;
    flex-direction: column;
    gap: 5px;
  }

  .focus-video-overlay {
    position: absolute;
    right: 10px;
    bottom: 10px;
    width: calc(100% - 20px);
    max-height: 62%;
    padding: 12px;
    border-radius: 16px;
    background: linear-gradient(90deg, rgba(3, 10, 9, 0.62), rgba(3, 10, 9, 0.92));
  }

  .focus-cue-list {
    grid-template-columns: 1fr;
    max-height: 150px;
    overflow: auto;
  }

  .focus-cue span,
  .focus-cue small {
    display: none;
  }

  .full-audio-player {
    grid-template-columns: 1fr;
  }

  .audio-symbol {
    display: none;
  }

  .full-audio-player audio,
  .listening-speed {
    grid-column: auto;
  }

  .listening-speed {
    justify-content: flex-start;
  }

  .shadow-steps {
    grid-template-columns: 1fr;
  }

  footer {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}