:root {
  color-scheme: light;
  --bg: #f4efe7;
  --bg-elevated: rgba(255, 251, 246, 0.82);
  --bg-strong: #fffaf2;
  --surface: rgba(255, 248, 239, 0.92);
  --surface-strong: #fffdf8;
  --border: rgba(69, 53, 32, 0.14);
  --border-strong: rgba(69, 53, 32, 0.22);
  --text: #1f1d1a;
  --text-muted: #5f564a;
  --accent: #b95c2e;
  --accent-strong: #90431b;
  --accent-soft: rgba(185, 92, 46, 0.12);
  --teal: #1f7a76;
  --gold: #c38a1e;
  --shadow: 0 24px 60px rgba(67, 41, 18, 0.12);
  --radius-xl: 0;
  --radius-lg: 22px;
  --radius-md: 16px;
  --radius-sm: 12px;
  --slide-padding: 60px 80px;
  --font-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-serif: "Noto Serif SC", "Songti SC", serif;
}

html[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0e1719;
  --bg-elevated: rgba(18, 31, 34, 0.82);
  --bg-strong: #111d20;
  --surface: rgba(19, 34, 38, 0.88);
  --surface-strong: rgba(23, 41, 45, 0.96);
  --border: rgba(210, 223, 216, 0.1);
  --border-strong: rgba(210, 223, 216, 0.18);
  --text: #f5efe4;
  --text-muted: #b8b1a3;
  --accent: #f1975d;
  --accent-strong: #ffbb86;
  --accent-soft: rgba(241, 151, 93, 0.14);
  --teal: #54c5b4;
  --gold: #f0bd57;
  --shadow: 0 28px 72px rgba(0, 0, 0, 0.28);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-snap-type: y mandatory;
  overflow-y: scroll;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input {
  font: inherit;
}

/* ── Full-width shell ── */
.site-shell {
  width: 100%;
  margin: 0;
  padding: 0;
}

/* ── Topbar: fixed full-width bar ── */
.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 24px;
  padding: 14px 40px;
  background: var(--bg-elevated);
  border: none;
  border-bottom: 1px solid var(--border);
  border-radius: 0;
  backdrop-filter: blur(18px);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
}

.brand {
  display: grid;
  gap: 2px;
  min-width: 0;
}

.brand strong {
  font-size: 1.1rem;
  font-weight: 800;
  letter-spacing: 0.03em;
}

.brand span:last-child {
  color: var(--text-muted);
  font-size: 0.92rem;
}

.brand__kicker {
  color: var(--accent);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.16em;
}

.topbar__nav {
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
}

.topbar__nav a {
  color: var(--text-muted);
  font-size: 0.92rem;
  transition: color 180ms ease, transform 180ms ease;
}

.topbar__nav a:hover,
.topbar__nav a:focus-visible {
  color: var(--text);
  transform: translateY(-1px);
}

.ghost-button,
.primary-button,
.secondary-button,
.chip,
.copy-button,
.file-picker {
  border: 1px solid transparent;
  border-radius: 999px;
  cursor: pointer;
  transition:
    transform 180ms ease,
    background-color 180ms ease,
    border-color 180ms ease,
    color 180ms ease,
    box-shadow 180ms ease;
}

.ghost-button {
  padding: 10px 16px;
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}

.ghost-button:hover,
.ghost-button:focus-visible,
.primary-button:hover,
.primary-button:focus-visible,
.secondary-button:hover,
.secondary-button:focus-visible,
.chip:hover,
.chip:focus-visible,
.copy-button:hover,
.copy-button:focus-visible,
.file-picker:hover,
.file-picker:focus-visible {
  transform: translateY(-1px);
}

/* ── Slide sections: each is a full-viewport slide ── */
.section {
  position: relative;
  width: 100%;
  min-height: 100vh;
  padding: var(--slide-padding);
  padding-top: 100px; /* space for fixed topbar */
  margin: 0;
  background:
    radial-gradient(ellipse at 10% 20%, rgba(200, 138, 30, 0.06), transparent 50%),
    radial-gradient(ellipse at 90% 80%, rgba(31, 122, 118, 0.06), transparent 50%),
    linear-gradient(180deg, var(--bg-strong), var(--bg));
  border: none;
  border-bottom: 1px solid var(--border);
  border-radius: 0;
  box-shadow: none;
  overflow: hidden;
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

/* ── Hero slide ── */
.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(300px, 0.7fr);
  gap: 48px;
  align-items: center;
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
}

.hero__backdrop {
  position: absolute;
  inset: auto -10% -18% 25%;
  height: 420px;
  background:
    radial-gradient(circle, rgba(31, 122, 118, 0.24), transparent 48%),
    radial-gradient(circle at 60% 40%, rgba(185, 92, 46, 0.2), transparent 36%);
  filter: blur(6px);
  pointer-events: none;
}

.hero__content,
.hero__panel,
.section-heading,
.overview-card,
.chart-card,
.library-sidebar,
.chapter-section,
.appendix-card {
  position: relative;
  z-index: 1;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 18px;
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.hero h1,
.section-heading h2 {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: -0.03em;
}

.hero h1 {
  max-width: 14ch;
  font-size: clamp(2.8rem, 4.5vw, 4.5rem);
}

.hero__lead,
.section-heading p,
.chapter-section__intro,
.scenario-card__text,
.scenario-card__value,
.appendix-card p,
.status-text {
  color: var(--text-muted);
  line-height: 1.75;
}

.chapter-section__intro,
.scenario-card__text,
.scenario-card__value {
  white-space: pre-line;
}

.hero__lead {
  max-width: 56ch;
  margin: 20px 0 0;
  font-size: 1.1rem;
}

.hero__stats,
.metric-stack,
.detail-list,
.chapter-overview,
.filter-bar,
.anchor-nav,
.appendix-grid {
  display: grid;
  gap: 14px;
}

.hero__stats {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 30px;
}

.stat-card,
.panel-card,
.overview-card,
.chart-card,
.sidebar-card,
.scenario-card,
.appendix-card {
  background: var(--surface-strong);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}

.stat-card {
  padding: 18px;
}

.stat-card__value {
  font-size: 1.75rem;
  font-weight: 800;
  letter-spacing: -0.04em;
}

.stat-card__label {
  margin-top: 8px;
  color: var(--text-muted);
  font-size: 0.92rem;
}

.hero__cta {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 24px;
}

.primary-button,
.secondary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 18px;
  min-height: 48px;
}

.primary-button {
  background: var(--accent);
  color: #fff8f3;
  box-shadow: 0 14px 30px rgba(185, 92, 46, 0.25);
}

.secondary-button {
  background: transparent;
  border-color: var(--border-strong);
}

.hero__panel {
  display: grid;
  gap: 18px;
  align-content: start;
}

.panel-card,
.overview-card,
.chart-card,
.sidebar-card,
.appendix-card {
  padding: 22px;
}

.panel-card--accent {
  background:
    linear-gradient(135deg, rgba(185, 92, 46, 0.14), transparent 60%),
    linear-gradient(180deg, var(--surface-strong), var(--surface-strong));
}

.panel-card__label,
.sidebar-card__label,
.chart-card__head span,
.overview-card__head .tag {
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.metric-pill {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 16px;
  background: var(--accent-soft);
  border-radius: var(--radius-md);
}

.metric-pill strong {
  font-weight: 700;
}

.hidden {
  display: none !important;
}

.file-loader {
  margin-top: 14px;
}

.file-picker {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 10px;
  padding: 12px 16px;
  background: var(--accent-soft);
  border-color: var(--border);
}

.file-picker input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}

/* ── Slide inner content wrapper ── */
.section-heading {
  max-width: 64ch;
  margin-bottom: 36px;
}

.section-heading h2 {
  font-size: clamp(2rem, 3.5vw, 3.2rem);
}

/* ── Non-hero slides: use inner max-width for readability ── */
#overview,
#analytics,
#prompt-lab {
  align-items: center;
}

#overview > *,
#analytics > *,
#prompt-lab > * {
  width: 100%;
  max-width: 1400px;
}

.overview-grid,
.analytics-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  width: 100%;
  max-width: 1400px;
}

.overview-card__head,
.chart-card__head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 18px;
}

.overview-card__head h3,
.chart-card__head h3,
.chapter-section__header h3,
.appendix-card h3,
.scenario-card__head h4 {
  margin: 0;
  font-size: 1.28rem;
}

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

.detail-list li {
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
}

.detail-list li:last-child {
  border-bottom: 0;
}

.detail-list strong {
  display: block;
  margin-bottom: 6px;
  color: var(--text);
}

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

.chapter-mini {
  padding: 16px;
  background: linear-gradient(180deg, var(--accent-soft), transparent);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
}

.chapter-mini strong {
  display: block;
  margin-bottom: 8px;
}

.chapter-mini p {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.94rem;
  line-height: 1.7;
}

.chart-card canvas {
  width: 100% !important;
  height: 340px !important;
}

/* ── Library slide: special — content may overflow, disable snap ── */
#library {
  min-height: 100vh;
  height: auto;
  scroll-snap-align: start;
  justify-content: flex-start;
  padding-top: 100px;
}

.toolbar {
  display: grid;
  gap: 18px;
  margin-bottom: 24px;
  max-width: 1400px;
  width: 100%;
}

.search-field {
  display: grid;
  gap: 10px;
}

.search-field span {
  font-weight: 700;
}

.search-field input {
  width: 100%;
  min-height: 52px;
  padding: 0 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--surface-strong);
  color: var(--text);
}

.filter-bar {
  grid-template-columns: repeat(auto-fit, minmax(140px, max-content));
  align-items: center;
}

.chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 16px;
  background: transparent;
  border-color: var(--border);
  color: var(--text-muted);
}

.chip.is-active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff8f3;
}

.library-layout {
  display: grid;
  grid-template-columns: 290px minmax(0, 1fr);
  gap: 24px;
  width: 100%;
  max-width: 1400px;
}

.library-sidebar {
  position: sticky;
  top: 80px;
  align-self: start;
  display: grid;
  gap: 16px;
}

.sidebar-card__value {
  margin: 10px 0 6px;
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.04em;
}

.sidebar-card__meta {
  margin: 0;
  color: var(--text-muted);
  line-height: 1.7;
}

.anchor-nav {
  max-height: 56vh;
  overflow: auto;
}

.anchor-nav a {
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  transition: background-color 180ms ease, color 180ms ease;
}

.anchor-nav a:hover,
.anchor-nav a:focus-visible,
.anchor-nav a.is-current {
  background: var(--accent-soft);
  color: var(--text);
}

.chapter-sections {
  display: grid;
  gap: 24px;
}

.chapter-section {
  padding: 24px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}

.chapter-section__header {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: end;
  margin-bottom: 12px;
}

.chapter-section__intro {
  margin: 0 0 18px;
}

.chapter-section__meta {
  color: var(--accent);
  font-weight: 700;
  white-space: nowrap;
}

.scenario-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.scenario-card {
  padding: 20px;
  display: grid;
  gap: 14px;
}

.scenario-card[hidden],
.chapter-section[hidden] {
  display: none !important;
}

.scenario-card__head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: start;
}

.scenario-card__index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 42px;
  height: 42px;
  padding: 0 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-weight: 800;
}

.scenario-card__audience {
  color: var(--text-muted);
  font-size: 0.92rem;
}

.scenario-card__text,
.scenario-card__value {
  margin: 0;
}

.scenario-card__label {
  margin-bottom: 6px;
  font-size: 0.92rem;
  font-weight: 800;
  color: var(--text);
}

.scenario-card__prompt {
  margin: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.scenario-card__prompt summary {
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
  font-weight: 700;
}

.scenario-card__prompt summary::-webkit-details-marker {
  display: none;
}

.scenario-card__prompt pre {
  margin: 0;
  padding: 0 16px 16px;
  white-space: pre-wrap;
  font-family: var(--font-sans);
  line-height: 1.8;
  color: var(--text-muted);
}

.scenario-card__actions {
  display: flex;
  justify-content: flex-end;
}

.copy-button {
  padding: 10px 14px;
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}

.copy-button.is-copied {
  background: var(--teal);
  border-color: var(--teal);
  color: #f8fffe;
}

.appendix-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  max-width: 1400px;
}

.appendix-card ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.appendix-card li {
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
  line-height: 1.75;
}

.appendix-card li:last-child {
  border-bottom: 0;
}

.appendix-card strong {
  color: var(--text);
}

.template-block {
  padding: 14px 16px;
  margin-top: 12px;
  background: var(--accent-soft);
  border-radius: var(--radius-md);
  white-space: pre-wrap;
  line-height: 1.75;
  color: var(--text-muted);
}

.footer {
  padding: 24px 40px;
  color: var(--text-muted);
  text-align: center;
  border-top: 1px solid var(--border);
  background: var(--bg-strong);
  scroll-snap-align: end;
}

.noscript-banner {
  padding: 16px;
  margin: 20px;
  text-align: center;
  border-radius: var(--radius-md);
  background: rgba(180, 48, 20, 0.12);
}

/* ── Slide number indicator ── */
.slide-indicator {
  position: fixed;
  bottom: 28px;
  right: 40px;
  z-index: 100;
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: center;
}

.slide-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--border-strong);
  border: none;
  cursor: pointer;
  padding: 0;
  transition: background-color 200ms ease, transform 200ms ease;
}

.slide-dot.is-active {
  background: var(--accent);
  transform: scale(1.3);
}

.slide-dot:hover {
  background: var(--accent-strong);
}

/* ── Reveal animation ── */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition:
    opacity 520ms ease,
    transform 520ms ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Responsive ── */
@media (max-width: 1080px) {
  :root {
    --slide-padding: 40px 40px;
  }

  .topbar {
    grid-template-columns: 1fr;
    justify-items: center;
    padding: 12px 20px;
  }

  .hero,
  .overview-grid,
  .analytics-grid,
  .library-layout,
  .appendix-grid {
    grid-template-columns: 1fr;
  }

  .library-sidebar {
    position: static;
  }
}

@media (max-width: 820px) {
  :root {
    --slide-padding: 24px 18px;
  }

  .section {
    padding-top: 80px;
  }

  .hero__stats,
  .chapter-overview,
  .scenario-grid {
    grid-template-columns: 1fr;
  }

  .topbar__nav {
    display: none;
  }

  .hero h1 {
    max-width: none;
  }

  .chapter-section__header,
  .scenario-card__head,
  .overview-card__head,
  .chart-card__head {
    flex-direction: column;
    align-items: start;
  }

  .slide-indicator {
    right: 16px;
    bottom: 16px;
  }
}