/* 《山行》：在 lesson-shell-v2 功能底座上建立纸艺秋山与枫径行旅皮肤。 */
body[data-visual-system="paper-cut-autumn-mountain"] {
  --lesson-bg: #211d18;
  --lesson-paper: #f4efe5;
  --lesson-ink: #2b2b27;
  --lesson-muted: #666158;
  --lesson-accent: #9f2f28;
  --lesson-accent-soft: #ead7bf;
  --lesson-gold: #c28a3f;
  --lesson-deep: #34332d;
  --lesson-line: rgba(43, 43, 39, .18);
  --lesson-shadow: 0 24px 80px rgba(32, 24, 17, .28);
  background:
    radial-gradient(circle at 84% 12%, rgba(159, 47, 40, .2), transparent 22rem),
    linear-gradient(180deg, #211d18 0, #39342b 42rem, #d5c7b3 68rem, #e8dfd1 100%);
}

body[data-visual-system="paper-cut-autumn-mountain"] .lesson-topbar {
  background: rgba(33, 29, 24, .95);
  border-bottom-color: rgba(194, 138, 63, .26);
}

body[data-visual-system="paper-cut-autumn-mountain"] .return-link::before {
  border-color: rgba(235, 208, 158, .76);
}

body[data-visual-system="paper-cut-autumn-mountain"] .lesson-hero {
  min-height: 630px;
  color: #f7f0e4;
  background: #302d27;
  border-color: rgba(194, 138, 63, .28);
  box-shadow: 0 32px 96px rgba(21, 16, 12, .46);
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy {
  position: relative;
  isolation: isolate;
  padding-inline: clamp(38px, 7vw, 82px);
  background:
    radial-gradient(circle at 17% 20%, rgba(194, 138, 63, .15), transparent 17rem),
    linear-gradient(145deg, #292821, #403b31);
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy::before,
body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy::after {
  content: "";
  position: absolute;
  z-index: -1;
  pointer-events: none;
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy::before {
  inset: 28px;
  border: 1px solid rgba(234, 215, 191, .15);
  border-radius: 28px 74px 28px 74px;
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy::after {
  right: clamp(20px, 5vw, 64px);
  bottom: 35px;
  width: 90px;
  height: 6px;
  background: linear-gradient(90deg, #c28a3f 0 56%, #9f2f28 56%);
  border-radius: 999px;
}

body[data-visual-system="paper-cut-autumn-mountain"] .lesson-mark,
body[data-visual-system="paper-cut-autumn-mountain"] .section-kicker {
  color: #8a2923;
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy .lesson-mark {
  color: #e5b466;
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy h1 {
  margin-block: 18px 12px;
  color: #fbf5e9;
  font-size: clamp(64px, 9vw, 108px);
  font-weight: 650;
  letter-spacing: .14em;
  white-space: nowrap;
}

.poem-author {
  margin: 0 0 22px;
  color: #d9c9b5;
  font-family: var(--lesson-serif);
  font-size: 19px;
  letter-spacing: .12em;
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-lead {
  color: rgba(247, 240, 228, .74);
}

body[data-visual-system="paper-cut-autumn-mountain"] .learning-path li {
  color: #f3e8d6;
  background: rgba(194, 138, 63, .14);
  border: 1px solid rgba(194, 138, 63, .27);
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-visual {
  min-height: 630px;
  background: #24221d;
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-visual::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(90deg, rgba(42, 37, 29, .24), transparent 34%),
    linear-gradient(180deg, transparent 62%, rgba(41, 28, 21, .24));
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-visual img {
  object-position: 50% 54%;
  filter: saturate(.9) contrast(1.02);
  animation: autumn-breathe 15s ease-in-out infinite alternate;
}

body[data-visual-system="paper-cut-autumn-mountain"] .hero-visual figcaption {
  z-index: 1;
  color: #f8eddb;
  background: rgba(42, 34, 27, .88);
  border: 1px solid rgba(194, 138, 63, .35);
}

@keyframes autumn-breathe {
  from { transform: scale(1); }
  to { transform: scale(1.026); }
}

body[data-visual-system="paper-cut-autumn-mountain"] .reader-dock {
  background: rgba(47, 42, 34, .97);
  border-color: rgba(194, 138, 63, .3);
  box-shadow: 0 18px 48px rgba(28, 20, 14, .38);
}

body[data-visual-system="paper-cut-autumn-mountain"] .mode-switch button[aria-pressed="true"],
body[data-visual-system="paper-cut-autumn-mountain"] .reader-actions button {
  color: #302a22;
  background: #f4efe5;
}

body[data-visual-system="paper-cut-autumn-mountain"] .lesson-section {
  background:
    linear-gradient(90deg, rgba(154, 107, 52, .035) 1px, transparent 1px),
    rgba(244, 239, 229, .98);
  background-size: 34px 100%;
  box-shadow: 0 16px 54px rgba(42, 31, 22, .14);
}

.shanhang-original-card {
  padding-block: clamp(38px, 6vw, 68px);
  text-align: center;
  background:
    radial-gradient(circle at 50% 48%, rgba(194, 138, 63, .15), transparent 19rem),
    linear-gradient(180deg, #fbf7ef, #e8dfd0);
}

.shanhang-original-card::before {
  content: "原诗";
  background: #34332d;
}

.shanhang-original-card [data-testid="textbook-original"] {
  font-size: clamp(25px, 3.8vw, 40px);
  font-weight: 640;
  letter-spacing: .1em;
  line-height: 2.15;
}

.poem-line {
  display: block;
}

.shanhang-couplet-grid {
  margin: 18px 0 24px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.shanhang-couplet-card {
  min-width: 0;
  padding: 15px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 14px;
  color: #f7f0e4;
  background: #34332d;
  border: 1px solid rgba(194, 138, 63, .38);
  border-radius: 16px;
}

.shanhang-couplet-card strong,
.shanhang-couplet-card span {
  display: block;
}

.shanhang-couplet-card strong {
  color: #e5b466;
  font-family: var(--lesson-serif);
  font-size: 18px;
}

.shanhang-couplet-card span {
  margin-top: 3px;
  color: rgba(247, 240, 228, .7);
  font-size: 13px;
}

.shanhang-couplet-card button {
  min-width: 96px;
  min-height: 48px;
  padding: 8px 14px;
  color: #382f27;
  cursor: pointer;
  background: #f4efe5;
  border: 0;
  border-radius: 999px;
  font-weight: 850;
}

.shanhang-pronunciations {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.shanhang-pronunciations .sound-card {
  min-height: 142px;
  background: linear-gradient(145deg, #eee4d4, #dfd0ba);
  border-color: rgba(154, 107, 52, .2);
}

.shanhang-notes {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.shanhang-notes .word-note {
  min-height: 142px;
  background: #ebe2d4;
  border-top: 4px solid #9a6b34;
}

.shanhang-notes .word-note:last-child {
  border-top-color: #9f2f28;
}

.shanhang-notes .word-note strong {
  font-family: var(--lesson-serif);
  font-size: 26px;
}

.meaning-spotlight {
  margin-top: 18px;
  padding: clamp(22px, 4vw, 36px);
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: clamp(20px, 4vw, 36px);
  color: #f7f0e4;
  background: linear-gradient(135deg, #35342e, #4b4032);
  border: 1px solid rgba(194, 138, 63, .4);
  border-radius: 20px;
}

.meaning-word {
  width: clamp(72px, 10vw, 108px);
  aspect-ratio: 1;
  display: grid;
  place-items: center;
  color: #f4efe5;
  background: #9f2f28;
  border-radius: 50%;
  font-family: var(--lesson-serif);
  font-size: clamp(42px, 6vw, 66px);
  font-weight: 700;
}

.meaning-spotlight strong {
  color: #e5b466;
  font-family: var(--lesson-serif);
  font-size: clamp(23px, 3vw, 32px);
}

.meaning-spotlight p {
  margin: 7px 0 0;
  color: rgba(247, 240, 228, .78);
}

.trail-section {
  overflow: hidden;
}

.mountain-trail {
  position: relative;
  display: grid;
  gap: 28px;
}

.mountain-trail::before {
  content: "";
  position: absolute;
  top: 5%;
  bottom: 5%;
  left: 50%;
  width: 2px;
  pointer-events: none;
  background: repeating-linear-gradient(180deg, #aa865c 0 10px, transparent 10px 20px);
  opacity: .42;
}

.mountain-stage {
  position: relative;
  z-index: 1;
  width: min(88%, 880px);
  min-width: 0;
  display: grid;
  grid-template-columns: minmax(220px, 290px) minmax(0, 1fr);
  overflow: hidden;
  color: #eee7dc;
  background: #302f2a;
  border: 1px solid rgba(154, 107, 52, .38);
  border-radius: 22px;
  box-shadow: 0 22px 58px rgba(38, 28, 20, .2);
}

.mountain-stage:nth-child(even) {
  margin-left: auto;
}

.mountain-stage:nth-child(even) .mountain-picture {
  order: 2;
}

.mountain-stage:nth-child(even) .mountain-copy {
  order: 1;
}

.mountain-picture {
  min-width: 0;
  margin: 0;
  display: grid;
  grid-template-rows: 1fr auto;
  background: #211f1b;
}

.mountain-picture img {
  width: 100%;
  height: 100%;
  max-height: 500px;
  display: block;
  object-fit: contain;
  background: #24221d;
  transition: filter .45s ease, transform .45s ease;
}

.mountain-stage:hover .mountain-picture img {
  filter: brightness(1.04);
  transform: scale(1.012);
}

.mountain-picture figcaption {
  padding: 10px 13px;
  color: #e5b466;
  background: #211f1b;
  font-size: 12px;
  font-weight: 850;
  letter-spacing: .08em;
}

.mountain-copy {
  min-width: 0;
  padding: clamp(24px, 5vw, 48px);
  align-self: center;
}

.stage-number {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  color: #f7f0e4;
  background: #9f2f28;
  border-radius: 50%;
  font-size: 12px;
  font-weight: 900;
}

.mountain-copy h3 {
  margin: 18px 0 9px;
  color: #f8f0e3;
  font-family: var(--lesson-serif);
  font-size: clamp(25px, 3.4vw, 36px);
  line-height: 1.25;
}

.mountain-copy p {
  margin: 0;
  color: rgba(238, 231, 220, .72);
  line-height: 1.8;
}

.mountain-copy b {
  margin-top: 18px;
  padding-top: 13px;
  display: block;
  color: #e5b466;
  border-top: 1px solid rgba(229, 180, 102, .2);
  font-size: 14px;
}

.autumn-evidence {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.evidence-card {
  min-width: 0;
  padding: clamp(22px, 4vw, 34px);
  color: #332f28;
  background: linear-gradient(145deg, #eee4d4, #dfd1bb);
  border: 1px solid rgba(154, 107, 52, .22);
  border-radius: 18px;
}

.evidence-card span {
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  color: #f8f1e5;
  background: #9a6b34;
  border-radius: 13px 13px 24px;
  font-family: var(--lesson-serif);
  font-size: 22px;
}

.evidence-card:last-child span {
  background: #9f2f28;
}

.evidence-card strong {
  margin-top: 18px;
  display: block;
  font-family: var(--lesson-serif);
  font-size: 27px;
}

.evidence-card p {
  margin: 6px 0 0;
  color: #5d574e;
}

.comparison-bridge {
  margin-top: 18px;
  padding: clamp(22px, 5vw, 42px);
  display: grid;
  grid-template-columns: minmax(0, 1fr) 58px minmax(0, 1fr);
  align-items: center;
  gap: 12px;
  text-align: center;
  background: #332f29;
  border-radius: 20px;
}

.comparison-bridge > div {
  padding: 18px;
  color: #f7f0e4;
  background: rgba(244, 239, 229, .08);
  border: 1px solid rgba(194, 138, 63, .28);
  border-radius: 14px;
}

.comparison-bridge span,
.comparison-bridge strong {
  display: block;
}

.comparison-bridge span {
  color: #e5b466;
  font-family: var(--lesson-serif);
  font-size: 28px;
}

.comparison-bridge strong {
  margin-top: 4px;
  color: rgba(247, 240, 228, .72);
  font-size: 14px;
}

.comparison-bridge > b {
  color: #f4efe5;
  font-family: var(--lesson-serif);
  font-size: 30px;
}

.comparison-bridge > p {
  grid-column: 1 / -1;
  margin: 8px 0 0;
  color: #f2dfbd;
}

.shanhang-recitation .recite-prompt,
.shanhang-recitation .recite-answer {
  white-space: normal;
}

body[data-visual-system="paper-cut-autumn-mountain"] .recite-panel {
  color: #f7f0e4;
  background:
    radial-gradient(circle at 86% 16%, rgba(159, 47, 40, .34), transparent 22rem),
    linear-gradient(145deg, #2c2a25, #443a2e);
}

.dictation-task {
  margin-top: 22px;
  padding: 17px 19px;
  color: #3a3028;
  background: #ead7bf;
  border-left: 5px solid #9f2f28;
  border-radius: 0 14px 14px 0;
}

.dictation-task strong {
  font-family: var(--lesson-serif);
  font-size: 20px;
}

.dictation-task p {
  margin: 5px 0 0;
}

body[data-visual-system="paper-cut-autumn-mountain"] .video-card video {
  max-height: 620px;
  background: #211f1b;
}

body[data-visual-system="paper-cut-autumn-mountain"] .disclosure,
body[data-visual-system="paper-cut-autumn-mountain"] .lesson-footer {
  color: #4f4941;
}

@media (max-width: 980px) {
  body[data-visual-system="paper-cut-autumn-mountain"] .lesson-hero {
    min-height: 540px;
    grid-template-columns: minmax(0, .9fr) minmax(280px, 1.1fr);
  }

  body[data-visual-system="paper-cut-autumn-mountain"] .hero-visual {
    min-height: 540px;
  }

  body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy h1 {
    font-size: clamp(50px, 7vw, 72px);
    letter-spacing: .08em;
  }

  .shanhang-couplet-grid {
    grid-template-columns: 1fr;
  }

  .shanhang-notes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .mountain-stage {
    width: 94%;
    grid-template-columns: minmax(200px, 250px) minmax(0, 1fr);
  }
}

@media (max-width: 680px) {
  body[data-visual-system="paper-cut-autumn-mountain"] .lesson-hero {
    min-height: 0;
    grid-template-columns: 1fr;
  }

  body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy::before {
    inset: 14px;
  }

  body[data-visual-system="paper-cut-autumn-mountain"] .hero-copy h1 {
    margin-top: 14px;
    font-size: clamp(54px, 16vw, 68px);
    letter-spacing: .1em;
  }

  body[data-visual-system="paper-cut-autumn-mountain"] .hero-visual {
    min-height: 360px;
    max-height: 400px;
  }

  .shanhang-original-card [data-testid="textbook-original"] {
    font-size: clamp(21px, 6vw, 27px);
    letter-spacing: .025em;
    line-height: 2.08;
  }

  .shanhang-pronunciations,
  .shanhang-notes,
  .autumn-evidence {
    grid-template-columns: 1fr;
  }

  .meaning-spotlight {
    grid-template-columns: 1fr;
  }

  .meaning-word {
    width: 78px;
  }

  .mountain-trail::before {
    left: 18px;
  }

  .mountain-stage,
  .mountain-stage:nth-child(even) {
    width: calc(100% - 12px);
    margin-left: 12px;
    grid-template-columns: 1fr;
  }

  .mountain-stage:nth-child(even) .mountain-picture,
  .mountain-stage:nth-child(even) .mountain-copy {
    order: initial;
  }

  .mountain-picture img {
    width: 100%;
    height: auto;
    max-height: 520px;
  }

  .comparison-bridge {
    grid-template-columns: 1fr;
  }

  .comparison-bridge > p {
    grid-column: auto;
  }
}

@media (max-width: 420px) {
  .shanhang-couplet-card {
    grid-template-columns: 1fr;
  }

  .shanhang-couplet-card button {
    width: 100%;
  }

  .mountain-copy {
    padding: 24px 20px 28px;
  }

  .comparison-bridge {
    padding: 18px;
  }
}

@media (prefers-reduced-motion: reduce) {
  body[data-visual-system="paper-cut-autumn-mountain"] .hero-visual img {
    animation: none;
  }

  .mountain-stage:hover .mountain-picture img {
    transform: none;
  }
}