:root {
  --bg: #f7f8f9;
  --paper: #ffffff;
  --ink: #15181d;
  --muted: #606a76;
  --line: #d9dde3;
  --burgundy: #7c1f35;
  --burgundy-dark: #4a1424;
  --teal: #0f7c86;
  --gold: #b9873c;
  --navy: #263848;
  --green: #2f7a52;
  --red: #b64242;
  --shadow: 0 22px 60px rgba(21, 24, 29, 0.12);
  --radius: 8px;
  --max: 1160px;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Noto Sans TC", "Microsoft JhengHei", "PingFang TC", Arial, sans-serif;
  line-height: 1.7;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
}

button,
select,
textarea {
  font: inherit;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: 28px;
  padding: 14px max(24px, calc((100vw - var(--max)) / 2));
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid rgba(217, 221, 227, 0.86);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  text-decoration: none;
  letter-spacing: 0;
}

.brand-mark {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.35), transparent),
    radial-gradient(circle at 36% 35%, var(--gold) 0 16%, transparent 17%),
    var(--burgundy);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.28);
}

.main-nav {
  display: flex;
  justify-content: flex-end;
  gap: 18px;
  font-size: 0.92rem;
  color: var(--muted);
}

.main-nav a {
  padding: 6px 2px;
  text-decoration: none;
  border-bottom: 2px solid transparent;
}

.main-nav a:hover,
.main-nav a:focus-visible,
.main-nav a.is-active {
  color: var(--burgundy);
  border-color: var(--burgundy);
}

.progress-shell {
  grid-column: 1 / -1;
  height: 3px;
  background: #eef0f3;
  overflow: hidden;
}

.progress-shell span {
  display: block;
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, var(--burgundy), var(--teal));
}

.hero {
  position: relative;
  min-height: 88vh;
  display: grid;
  align-items: center;
  overflow: hidden;
  background: #111820;
}

.hero-media,
.hero-shade {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero-media {
  object-fit: cover;
}

.hero-shade {
  background:
    linear-gradient(90deg, rgba(9, 12, 16, 0.82) 0%, rgba(9, 12, 16, 0.54) 48%, rgba(9, 12, 16, 0.2) 100%),
    linear-gradient(0deg, rgba(9, 12, 16, 0.72) 0%, transparent 34%);
}

.hero-content {
  position: relative;
  width: min(760px, calc(100% - 48px));
  margin-left: max(24px, calc((100vw - var(--max)) / 2));
  padding: 112px 0 132px;
  color: #fff;
}

.course-label,
.section-kicker {
  margin: 0 0 10px;
  color: var(--teal);
  font-size: 0.86rem;
  font-weight: 800;
}

.course-label {
  color: #e9c276;
}

.hero h1 {
  max-width: 700px;
  margin: 0;
  font-size: clamp(2.5rem, 6vw, 5.8rem);
  line-height: 1.05;
  letter-spacing: 0;
}

.hero-subtitle {
  max-width: 620px;
  margin: 24px 0 0;
  color: #f5e8d2;
  font-size: clamp(1.05rem, 2vw, 1.35rem);
  font-weight: 700;
}

.hero-copy {
  max-width: 680px;
  margin: 18px 0 0;
  color: rgba(255, 255, 255, 0.86);
  font-size: 1.06rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.button {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 18px;
  border-radius: var(--radius);
  border: 1px solid transparent;
  font-size: 0.95rem;
  font-weight: 800;
  text-decoration: none;
  cursor: pointer;
}

.button.primary {
  background: var(--gold);
  color: #111820;
}

.button.ghost {
  border-color: rgba(255, 255, 255, 0.36);
  color: #fff;
  background: rgba(255, 255, 255, 0.08);
}

.hero-strip {
  position: absolute;
  left: max(24px, calc((100vw - var(--max)) / 2));
  right: max(24px, calc((100vw - var(--max)) / 2));
  bottom: 24px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 10px;
  align-items: center;
  color: rgba(255, 255, 255, 0.86);
  font-weight: 800;
}

.hero-strip span {
  min-width: 0;
  padding: 10px 14px;
  border: 1px solid rgba(255, 255, 255, 0.24);
  background: rgba(9, 12, 16, 0.46);
  border-radius: var(--radius);
  text-align: center;
}

.reader-map,
.quiz-band,
.page-shell {
  width: min(var(--max), calc(100% - 48px));
  margin: 0 auto;
}

.reader-map {
  padding: 74px 0 36px;
}

.reader-map h2,
.quiz-band h2,
.content-section h2 {
  margin: 0;
  line-height: 1.25;
  letter-spacing: 0;
}

.reader-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
  margin-top: 24px;
}

.reader-grid article {
  min-height: 150px;
  padding: 22px;
  border: 1px solid var(--line);
  background: var(--paper);
  border-radius: var(--radius);
}

.reader-grid strong {
  display: block;
  color: var(--burgundy);
  font-size: 1.18rem;
}

.reader-grid span {
  display: block;
  margin-top: 10px;
  color: var(--muted);
}

.quiz-band {
  display: grid;
  grid-template-columns: minmax(260px, 0.8fr) minmax(320px, 1.2fr);
  gap: 28px;
  align-items: start;
  padding: 34px;
  margin-top: 38px;
  border-radius: var(--radius);
  background: #182636;
  color: #fff;
  box-shadow: var(--shadow);
}

.quiz-band p {
  color: rgba(255, 255, 255, 0.78);
}

.page-shell {
  display: grid;
  grid-template-columns: 230px minmax(0, 1fr);
  gap: 34px;
  padding: 72px 0 96px;
}

.side-rail {
  position: relative;
}

.rail-card {
  position: sticky;
  top: 110px;
  padding: 18px;
  border: 1px solid var(--line);
  background: var(--paper);
  border-radius: var(--radius);
}

.rail-title {
  display: block;
  color: var(--burgundy);
  font-weight: 900;
}

.rail-card ol {
  padding-left: 20px;
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.sections {
  display: grid;
  gap: 26px;
}

.content-section {
  padding: clamp(28px, 5vw, 52px);
  border: 1px solid var(--line);
  background: var(--paper);
  border-radius: var(--radius);
  box-shadow: 0 12px 28px rgba(21, 24, 29, 0.05);
}

.accent-section {
  border-color: rgba(15, 124, 134, 0.28);
  background:
    linear-gradient(135deg, rgba(15, 124, 134, 0.08), transparent 36%),
    var(--paper);
}

.conclusion-section {
  border-color: rgba(124, 31, 53, 0.28);
}

.section-heading {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 18px;
  align-items: start;
  margin-bottom: 26px;
}

.section-number {
  display: inline-flex;
  width: 54px;
  height: 54px;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: #eef5f6;
  color: var(--teal);
  font-weight: 900;
}

.split-layout,
.media-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(300px, 0.86fr);
  gap: 28px;
  align-items: center;
}

.media-row.reverse {
  grid-template-columns: minmax(300px, 0.95fr) minmax(0, 1fr);
}

.prose p {
  margin: 0 0 16px;
}

.lead {
  color: #273342;
  font-size: 1.2rem;
  font-weight: 800;
}

.callout,
.liquidity-box,
.two-column-note {
  border-radius: var(--radius);
  border: 1px solid rgba(185, 135, 60, 0.34);
  background: #fffaf1;
}

.callout {
  padding: 16px 18px;
  color: #5f431f;
  font-weight: 800;
}

.two-column-note {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  margin-top: 22px;
  overflow: hidden;
}

.two-column-note div {
  padding: 18px;
}

.two-column-note div + div {
  border-left: 1px solid rgba(185, 135, 60, 0.28);
}

.two-column-note h3,
.liquidity-box h3,
.source-grid h3 {
  margin: 0 0 8px;
  font-size: 1rem;
}

.two-column-note p,
.liquidity-box p {
  margin: 0;
}

.section-image {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.chart-card {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: #fbfcfd;
  cursor: pointer;
}

.chart-card:focus-within,
.chart-card:hover {
  border-color: rgba(15, 124, 134, 0.52);
  box-shadow: 0 18px 42px rgba(15, 124, 134, 0.12);
}

.chart-card img {
  width: 100%;
  background: #fff;
}

.chart-card figcaption {
  padding: 12px 16px;
  color: var(--muted);
  font-size: 0.92rem;
  border-top: 1px solid var(--line);
}

.liquidity-box {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 18px;
  align-items: center;
  padding: 18px 22px;
  margin-bottom: 26px;
}

.liquidity-box ol {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.liquidity-box li {
  padding: 12px;
  border-radius: var(--radius);
  background: #fff;
  border: 1px solid rgba(185, 135, 60, 0.26);
  font-weight: 700;
}

.quiz-stack {
  display: grid;
  gap: 14px;
  margin-top: 22px;
}

.quiz-card {
  padding: 18px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: #fff;
}

.quiz-band .quiz-card {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.18);
}

.quiz-title {
  margin: 0 0 10px;
  font-weight: 900;
}

.quiz-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 12px;
}

.choice-button,
.check-button,
.classifier-button {
  min-height: 40px;
  padding: 8px 14px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  font-weight: 800;
  cursor: pointer;
}

.quiz-band .choice-button,
.quiz-band .check-button {
  border-color: rgba(255, 255, 255, 0.28);
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
}

.choice-button:hover,
.choice-button:focus-visible,
.check-button:hover,
.check-button:focus-visible,
.classifier-button:hover,
.classifier-button:focus-visible {
  border-color: var(--teal);
}

.choice-button.is-selected,
.classifier-button.is-selected {
  border-color: var(--teal);
  background: #e9f6f7;
  color: #0b5960;
}

.choice-button.is-correct,
.classifier-button.is-correct {
  border-color: var(--green);
  background: #eaf5ef;
  color: #21573a;
}

.choice-button.is-wrong,
.classifier-button.is-wrong {
  border-color: var(--red);
  background: #f9eaea;
  color: #8c2c2c;
}

.feedback {
  min-height: 26px;
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 0.94rem;
}

.quiz-band .feedback {
  color: rgba(255, 255, 255, 0.84);
}

.matching-grid,
.classifier-grid {
  display: grid;
  gap: 12px;
}

.matching-row {
  display: grid;
  grid-template-columns: minmax(130px, 0.6fr) minmax(180px, 1fr);
  gap: 10px;
  align-items: center;
}

.matching-row strong {
  display: block;
}

.matching-row select {
  width: 100%;
  min-height: 42px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 8px 10px;
  background: #fff;
}

.classifier-item {
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfcfd;
}

.classifier-item p {
  margin: 0 0 10px;
  font-weight: 800;
}

.reflection-panel {
  display: grid;
  gap: 14px;
  margin-top: 24px;
}

.reflection-card {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfcfd;
}

.reflection-card label {
  display: block;
  margin-bottom: 10px;
  font-weight: 900;
}

.reflection-card textarea {
  width: 100%;
  min-height: 110px;
  resize: vertical;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 12px;
  background: #fff;
  color: var(--ink);
}

.source-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}

.source-grid article {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfcfd;
}

.source-grid ul {
  padding-left: 20px;
  margin: 0;
}

.source-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

.source-links a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 8px 12px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  color: var(--teal);
  font-weight: 800;
  text-decoration: none;
  background: #fff;
}

.source-note {
  margin: 18px 0 0;
  color: var(--muted);
}

.chart-drawer {
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 50;
  width: min(420px, calc(100% - 40px));
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  box-shadow: var(--shadow);
}

.drawer-close {
  position: absolute;
  top: 8px;
  right: 8px;
  width: 34px;
  height: 34px;
  border: 0;
  border-radius: 50%;
  background: #eef0f3;
  color: var(--ink);
  font-size: 1.5rem;
  line-height: 1;
  cursor: pointer;
}

.chart-drawer h3 {
  margin: 0 34px 8px 0;
}

.chart-drawer ul {
  padding-left: 20px;
  margin-bottom: 0;
}

@media (max-width: 980px) {
  .site-header {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .main-nav {
    justify-content: flex-start;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .reader-grid,
  .source-grid {
    grid-template-columns: 1fr 1fr;
  }

  .quiz-band,
  .page-shell,
  .split-layout,
  .media-row,
  .media-row.reverse,
  .liquidity-box {
    grid-template-columns: 1fr;
  }

  .side-rail {
    display: none;
  }

  .liquidity-box ol {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .site-header,
  .reader-map,
  .quiz-band,
  .page-shell {
    width: min(100% - 28px, var(--max));
  }

  .site-header {
    padding-left: 14px;
    padding-right: 14px;
  }

  .hero {
    min-height: 92vh;
  }

  .hero-content {
    width: calc(100% - 28px);
    margin-left: 14px;
    padding-top: 92px;
  }

  .hero-strip {
    left: 14px;
    right: 14px;
    grid-template-columns: 1fr;
  }

  .hero-strip span {
    padding: 8px 10px;
  }

  .reader-grid,
  .source-grid,
  .two-column-note,
  .matching-row {
    grid-template-columns: 1fr;
  }

  .two-column-note div + div {
    border-left: 0;
    border-top: 1px solid rgba(185, 135, 60, 0.28);
  }

  .content-section,
  .quiz-band {
    padding: 22px;
  }

  .section-heading {
    grid-template-columns: 1fr;
  }

  .section-number {
    width: 44px;
    height: 44px;
  }
}

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