:root {
  --bg: #f6f0e4;
  --bg-deep: #efe2ca;
  --panel: rgba(255, 251, 244, 0.88);
  --panel-strong: rgba(255, 248, 239, 0.96);
  --ink: #241b16;
  --ink-soft: #594940;
  --ink-dim: #8a786f;
  --line: rgba(91, 59, 46, 0.16);
  --line-strong: rgba(91, 59, 46, 0.28);
  --wine: #8e2f2a;
  --wine-soft: rgba(142, 47, 42, 0.12);
  --ochre: #ba7e2d;
  --ochre-soft: rgba(186, 126, 45, 0.14);
  --teal: #1f6a67;
  --teal-soft: rgba(31, 106, 103, 0.1);
  --shadow: 0 22px 56px rgba(66, 39, 26, 0.14);
  --radius-xl: 34px;
  --radius-lg: 24px;
  --radius-md: 18px;
  --radius-sm: 14px;
  --max-width: 1360px;
}

* {
  box-sizing: border-box;
  min-width: 0;
}

html {
  scroll-behavior: smooth;
  background:
    radial-gradient(circle at 0% 0%, rgba(186, 126, 45, 0.18), transparent 24%),
    radial-gradient(circle at 100% 18%, rgba(31, 106, 103, 0.12), transparent 26%),
    linear-gradient(180deg, #f7f1e7 0%, #f3eadc 52%, #efe3cf 100%);
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  font-family: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
  background: transparent;
  overflow-x: clip;
}

h1,
h2,
h3,
p,
li,
a,
button,
span {
  overflow-wrap: anywhere;
}

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

button {
  font: inherit;
}

.paper {
  position: fixed;
  border-radius: 999px;
  filter: blur(46px);
  pointer-events: none;
  z-index: 0;
  opacity: 0.72;
}

.paper-a {
  top: -120px;
  left: -90px;
  width: 360px;
  height: 360px;
  background: rgba(186, 126, 45, 0.22);
}

.paper-b {
  top: 30%;
  right: -100px;
  width: 320px;
  height: 320px;
  background: rgba(31, 106, 103, 0.16);
}

.paper-c {
  bottom: -160px;
  left: 26%;
  width: 440px;
  height: 440px;
  background: rgba(142, 47, 42, 0.12);
}

.hero,
.nav,
.page,
.footer {
  position: relative;
  z-index: 1;
}

.panel,
.nav,
.footer,
.metric-card,
.domain-card,
.tool-card,
.quote-card,
.timeline-card,
.debate-card,
.method-card,
.route-card,
.step-card {
  border: 1px solid var(--line);
  background:
    linear-gradient(165deg, rgba(255, 255, 255, 0.5), rgba(255, 247, 237, 0.28)),
    var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
}

.hero {
  width: min(var(--max-width), calc(100vw - 32px));
  margin: 0 auto;
  padding: 40px 0 28px;
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) 360px;
  gap: 26px;
  align-items: center;
}

.hero-main,
.cover-card,
.thesis-card,
.section,
.footer,
.nav {
  border-radius: var(--radius-xl);
}

.hero-main {
  padding: 34px;
}

.hero-side {
  display: grid;
  gap: 18px;
}

.eyebrow {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--wine);
}

.hero-title,
.section-head h2,
.cover-title,
.cover-note h2,
.thesis-card h2,
.subhead h3,
.part-button strong,
.detail-head h3,
.step-copy h3,
.aside-card h3,
.timeline-card h3,
.quote-card h3,
.debate-card h3,
.method-card h3,
.route-card h3 {
  font-family: "Songti SC", "STSong", "Noto Serif SC", serif;
}

.hero-title {
  margin: 18px 0 0;
  font-size: clamp(3rem, 7vw, 6rem);
  line-height: 0.94;
  letter-spacing: -0.06em;
}

.hero-title span {
  display: block;
  margin-top: 12px;
  color: var(--wine);
  font-size: clamp(1.2rem, 2.5vw, 2rem);
  line-height: 1.12;
  letter-spacing: -0.03em;
}

.hero-summary {
  max-width: 760px;
  margin: 24px 0 0;
  font-size: 1.08rem;
  line-height: 1.88;
  color: var(--ink-soft);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 18px;
  border-radius: 999px;
  border: 1px solid transparent;
  transition: transform 180ms ease, background-color 180ms ease, border-color 180ms ease;
}

.button:hover,
.button:focus-visible,
.nav a:hover,
.nav a:focus-visible,
.part-button:hover,
.part-button:focus-visible,
.method-filter button:hover,
.method-filter button:focus-visible {
  transform: translateY(-1px);
  outline: none;
}

.button-primary {
  color: #fff8f1;
  background: linear-gradient(135deg, #8e2f2a 0%, #b24730 100%);
}

.button-secondary {
  color: var(--wine);
  background: rgba(255, 252, 247, 0.7);
  border-color: rgba(142, 47, 42, 0.2);
}

.metric-grid {
  margin-top: 28px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.metric-card {
  border-radius: var(--radius-md);
  padding: 18px;
}

.metric-card span {
  display: block;
  font-size: 12px;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--wine);
}

.metric-card strong {
  display: block;
  margin-top: 8px;
  font-size: 2rem;
  line-height: 1;
  color: var(--ink);
}

.metric-card p,
.cover-note p,
.thesis-card p,
.section-head p,
.subhead p,
.step-copy p,
.aside-card p,
.timeline-card p,
.quote-card p,
.debate-card p,
.method-card p,
.route-card p,
.detail-body p,
.detail-list li {
  color: var(--ink-soft);
  line-height: 1.8;
}

.cover-card {
  padding: 18px;
}

.cover-art {
  position: relative;
  overflow: hidden;
  min-height: 370px;
  padding: 22px;
  border-radius: 26px;
  background:
    linear-gradient(155deg, rgba(36, 27, 22, 0.94), rgba(88, 42, 28, 0.95)),
    #301d17;
  color: #f7ebd8;
}

.cover-kicker {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: rgba(247, 235, 216, 0.72);
}

.cover-title {
  margin: 22px 0 0;
  font-size: clamp(3.4rem, 8vw, 4.8rem);
  line-height: 0.92;
  letter-spacing: -0.07em;
}

.cover-line {
  max-width: 220px;
  margin: 12px 0 0;
  color: rgba(247, 235, 216, 0.82);
  line-height: 1.7;
}

.cover-stair {
  position: absolute;
  right: 20px;
  bottom: 26px;
  display: flex;
  align-items: flex-end;
  gap: 10px;
}

.cover-stair span {
  width: 26px;
  border-radius: 14px 14px 6px 6px;
  background: linear-gradient(180deg, rgba(245, 177, 80, 0.96), rgba(142, 47, 42, 0.92));
}

.cover-stair span:nth-child(1) {
  height: 54px;
}

.cover-stair span:nth-child(2) {
  height: 88px;
}

.cover-stair span:nth-child(3) {
  height: 132px;
}

.cover-stair span:nth-child(4) {
  height: 186px;
}

.cover-ring {
  position: absolute;
  inset: 90px -20px auto auto;
  width: 180px;
  height: 180px;
  border: 1px solid rgba(247, 235, 216, 0.16);
  border-radius: 999px;
}

.cover-note {
  margin-top: 16px;
  padding: 2px 2px 4px;
}

.thesis-card {
  padding: 24px;
}

.thesis-card h2,
.cover-note h2 {
  margin: 10px 0 0;
  font-size: 1.6rem;
  line-height: 1.25;
}

.nav {
  width: min(var(--max-width), calc(100vw - 32px));
  margin: 0 auto;
  padding: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  position: sticky;
  top: 14px;
  z-index: 3;
}

.nav a {
  padding: 10px 14px;
  border-radius: 999px;
  font-size: 0.95rem;
  color: var(--ink-soft);
  transition: transform 180ms ease, color 180ms ease, background-color 180ms ease;
}

.nav a:hover,
.nav a:focus-visible {
  background: rgba(142, 47, 42, 0.08);
  color: var(--wine);
}

.page {
  width: min(var(--max-width), calc(100vw - 32px));
  margin: 26px auto 0;
  display: grid;
  gap: 22px;
}

.section {
  padding: 30px;
}

.section-head {
  display: grid;
  gap: 10px;
}

.section-head h2 {
  margin: 0;
  font-size: clamp(2rem, 4vw, 3rem);
  line-height: 1.03;
  letter-spacing: -0.05em;
}

.section-head p {
  margin: 0;
  max-width: 780px;
}

.overview-grid,
.tool-grid,
.debate-grid,
.quote-grid,
.method-grid,
.route-grid {
  margin-top: 24px;
}

.overview-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 14px;
}

.overview-card {
  display: grid;
  gap: 12px;
  padding: 18px;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: rgba(255, 250, 243, 0.7);
}

.overview-card .index {
  display: inline-flex;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  align-items: center;
  justify-content: center;
  color: var(--wine);
  background: rgba(142, 47, 42, 0.08);
  font-weight: 700;
}

.overview-card h3,
.domain-card h3 {
  margin: 0;
  font-size: 1.15rem;
}

.overview-card p,
.domain-card p {
  margin: 0;
  color: var(--ink-soft);
  line-height: 1.74;
}

.map-layout {
  margin-top: 24px;
  display: grid;
  grid-template-columns: minmax(0, 1.06fr) minmax(0, 0.94fr);
  gap: 18px;
}

.map-panel {
  padding: 22px;
  border-radius: var(--radius-lg);
}

.subhead h3 {
  margin: 8px 0 0;
  font-size: 1.45rem;
}

.subhead p {
  margin: 6px 0 0;
}

.domain-list,
.tool-grid {
  display: grid;
  gap: 14px;
}

.domain-list {
  margin-top: 20px;
}

.domain-card {
  padding: 18px;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: rgba(255, 251, 245, 0.72);
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}

.tag {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 0 10px;
  border-radius: 999px;
  font-size: 0.84rem;
  color: var(--wine);
  background: rgba(142, 47, 42, 0.08);
}

.tool-grid {
  margin-top: 20px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.tool-card {
  padding: 18px;
  border-radius: var(--radius-md);
}

.tool-card h3,
.quote-card h3,
.debate-card h3,
.method-card h3,
.route-card h3 {
  margin: 0;
  font-size: 1.16rem;
}

.tool-card p,
.quote-card p,
.debate-card p,
.method-card p,
.route-card p {
  margin: 10px 0 0;
}

.parts-layout {
  margin-top: 24px;
  display: grid;
  grid-template-columns: 320px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.part-tabs {
  display: grid;
  gap: 10px;
}

.part-button {
  width: 100%;
  display: grid;
  gap: 8px;
  padding: 16px 18px;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: rgba(255, 249, 241, 0.72);
  color: inherit;
  text-align: left;
  cursor: pointer;
  transition: transform 180ms ease, border-color 180ms ease, background-color 180ms ease;
}

.part-button strong {
  font-size: 1.08rem;
}

.part-button span {
  color: var(--ink-dim);
  line-height: 1.6;
}

.part-button.is-active {
  border-color: rgba(142, 47, 42, 0.4);
  background: linear-gradient(160deg, rgba(142, 47, 42, 0.08), rgba(255, 248, 240, 0.92));
}

.part-detail {
  padding: 24px;
}

.detail-head {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 16px;
  align-items: baseline;
}

.detail-head h3 {
  margin: 0;
  font-size: 2rem;
}

.detail-range {
  color: var(--wine);
  font-size: 0.95rem;
}

.detail-kicker {
  margin: 12px 0 0;
  color: var(--ink);
  font-size: 1.08rem;
}

.detail-body {
  margin-top: 18px;
  display: grid;
  gap: 18px;
}

.detail-list {
  margin: 0;
  padding-left: 18px;
  display: grid;
  gap: 8px;
}

.detail-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.algorithm-layout {
  margin-top: 24px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 18px;
}

.algorithm-steps {
  display: grid;
  gap: 14px;
}

.step-card {
  display: grid;
  grid-template-columns: 68px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  padding: 18px;
  border-radius: var(--radius-md);
}

.step-index {
  display: inline-flex;
  width: 52px;
  height: 52px;
  align-items: center;
  justify-content: center;
  border-radius: 16px;
  background: linear-gradient(135deg, rgba(142, 47, 42, 0.16), rgba(186, 126, 45, 0.12));
  color: var(--wine);
  font-weight: 700;
  font-size: 1.1rem;
}

.step-copy h3 {
  margin: 0;
  font-size: 1.35rem;
}

.step-copy p {
  margin: 10px 0 0;
}

.step-note {
  margin-top: 12px;
  padding: 10px 12px;
  border-left: 3px solid rgba(142, 47, 42, 0.22);
  background: rgba(142, 47, 42, 0.05);
  color: var(--ink);
}

.algorithm-notes {
  display: grid;
  gap: 14px;
}

.aside-card {
  padding: 20px;
  border-radius: var(--radius-md);
}

.aside-card h3 {
  margin: 10px 0 0;
  font-size: 1.26rem;
  line-height: 1.3;
}

.timeline-list {
  position: relative;
  margin-top: 24px;
  display: grid;
  gap: 14px;
}

.timeline-list::before {
  content: "";
  position: absolute;
  left: 20px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(180deg, rgba(142, 47, 42, 0.3), rgba(31, 106, 103, 0.2));
}

.timeline-card {
  position: relative;
  margin-left: 46px;
  padding: 18px 18px 18px 22px;
  border-radius: var(--radius-md);
}

.timeline-card::before {
  content: "";
  position: absolute;
  left: -35px;
  top: 22px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--wine);
  box-shadow: 0 0 0 8px rgba(142, 47, 42, 0.1);
}

.timeline-year {
  display: inline-flex;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--wine);
  background: rgba(142, 47, 42, 0.08);
}

.timeline-card h3 {
  margin: 12px 0 0;
  font-size: 1.22rem;
}

.timeline-card p {
  margin: 10px 0 0;
}

.quote-grid,
.debate-grid,
.route-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.quote-card,
.debate-card,
.route-card {
  padding: 20px;
  border-radius: var(--radius-md);
}

.quote-card blockquote {
  margin: 12px 0 0;
  padding: 0;
  border: 0;
  font-family: "Songti SC", "STSong", "Noto Serif SC", serif;
  font-size: 1.2rem;
  line-height: 1.7;
  color: var(--ink);
}

.quote-source {
  margin-top: 12px;
  color: var(--ink-dim);
  font-size: 0.92rem;
}

.debate-card {
  display: grid;
  gap: 10px;
}

.debate-answer {
  padding-top: 10px;
  border-top: 1px solid var(--line);
}

.method-shell {
  margin-top: 24px;
  padding: 18px;
}

.method-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.method-filter button {
  min-height: 40px;
  padding: 0 14px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(255, 248, 240, 0.9);
  color: var(--ink-soft);
  cursor: pointer;
  transition: transform 180ms ease, color 180ms ease, background-color 180ms ease, border-color 180ms ease;
}

.method-filter button.is-active {
  color: #fff8f1;
  background: linear-gradient(135deg, #8e2f2a 0%, #b24730 100%);
  border-color: transparent;
}

.method-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin-top: 18px;
}

.method-card {
  padding: 18px;
  border-radius: var(--radius-md);
}

.method-chip {
  display: inline-flex;
  align-items: center;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 0.82rem;
  color: var(--teal);
  background: rgba(31, 106, 103, 0.08);
}

.route-grid {
  margin-top: 24px;
}

.route-card ul {
  margin: 12px 0 0;
  padding-left: 18px;
  color: var(--ink-soft);
  line-height: 1.74;
  display: grid;
  gap: 8px;
}

.footer {
  width: min(var(--max-width), calc(100vw - 32px));
  margin: 22px auto 36px;
  padding: 18px 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: space-between;
  align-items: center;
  color: var(--ink-soft);
}

.footer a {
  color: var(--wine);
}

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 560ms ease, transform 560ms ease;
}

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

@media (max-width: 1120px) {
  .hero,
  .map-layout,
  .parts-layout,
  .algorithm-layout {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
    padding-top: 28px;
  }

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

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

@media (max-width: 760px) {
  .hero,
  .nav,
  .page,
  .footer {
    width: min(calc(100vw - 20px), var(--max-width));
  }

  .hero-main,
  .section,
  .footer,
  .cover-card,
  .thesis-card {
    border-radius: 24px;
  }

  .hero-main,
  .section,
  .cover-card,
  .thesis-card {
    padding: 22px;
  }

  .hero-title {
    font-size: clamp(2.5rem, 14vw, 4.2rem);
  }

  .metric-grid,
  .overview-grid,
  .tool-grid,
  .quote-grid,
  .debate-grid,
  .route-grid,
  .method-grid {
    grid-template-columns: 1fr;
  }

  .nav {
    top: 10px;
    justify-content: flex-start;
    overflow-x: auto;
    scrollbar-width: none;
  }

  .nav::-webkit-scrollbar {
    display: none;
  }

  .step-card {
    grid-template-columns: 1fr;
  }

  .timeline-card {
    margin-left: 30px;
  }

  .timeline-card::before {
    left: -22px;
  }

  .timeline-list::before {
    left: 12px;
  }
}