:root {
  --paper: #f2ede3;
  --paper-deep: #e7dfd1;
  --paper-light: #faf7f0;
  --ink: #142b3a;
  --ink-soft: #344957;
  --muted: #6b777c;
  --route: #a64231;
  --route-dark: #843528;
  --line: rgba(20, 43, 58, 0.18);
  --line-strong: rgba(20, 43, 58, 0.42);
  --serif: "Iowan Old Style", "Songti SC", "STSong", "Noto Serif CJK SC", Georgia, serif;
  --sans: "Avenir Next", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --page: 1280px;
  --reading: 740px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 6rem;
}

body {
  margin: 0;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    linear-gradient(rgba(20, 43, 58, 0.018) 1px, transparent 1px),
    linear-gradient(90deg, rgba(20, 43, 58, 0.014) 1px, transparent 1px);
  background-size: 28px 28px;
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:hover {
  color: var(--route);
}

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

button,
input {
  font: inherit;
}

:focus-visible {
  outline: 3px solid var(--route);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  z-index: 1000;
  top: 0.7rem;
  left: 0.7rem;
  padding: 0.55rem 0.8rem;
  color: var(--paper-light);
  background: var(--ink);
  transform: translateY(-150%);
}

.skip-link:focus {
  transform: translateY(0);
}

.reading-progress {
  position: fixed;
  z-index: 120;
  top: 0;
  right: 0;
  left: 0;
  height: 3px;
}

.reading-progress span {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--route);
  transform: scaleX(0);
  transform-origin: left;
  will-change: transform;
}

.site-header {
  position: sticky;
  z-index: 100;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 74px;
  padding: 0 4vw;
  border-bottom: 1px solid var(--line);
  background: rgba(242, 237, 227, 0.94);
  backdrop-filter: blur(12px);
}

.site-mark {
  display: inline-flex;
  align-items: baseline;
  gap: 0.6rem;
  color: var(--ink);
  text-decoration: none;
}

.site-mark:hover {
  color: var(--ink);
}

.site-mark-en {
  font-family: var(--mono);
  font-size: 1.18rem;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.site-mark-cn {
  padding-left: 0.65rem;
  border-left: 1px solid var(--line-strong);
  font-family: var(--serif);
  font-size: 0.96rem;
  font-weight: 700;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(1.1rem, 3vw, 2.8rem);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.site-nav a {
  text-decoration: none;
}

.nav-toggle {
  display: none;
  color: var(--ink);
  border: 0;
  background: transparent;
  font-size: 0.82rem;
  font-weight: 700;
}

.site-main {
  min-height: 65vh;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(360px, 0.72fr);
  gap: clamp(3rem, 7vw, 8rem);
  align-items: center;
  max-width: var(--page);
  min-height: calc(100vh - 74px);
  margin: 0 auto;
  padding: clamp(4rem, 9vh, 8rem) 4vw;
}

.edition-line {
  display: flex;
  gap: 1rem;
  justify-content: space-between;
  margin: 0 0 2.4rem;
  padding-bottom: 0.7rem;
  color: var(--muted);
  border-bottom: 1px solid var(--line-strong);
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.hero h1 {
  margin: 0;
  font-family: var(--serif);
  font-weight: 800;
  letter-spacing: -0.055em;
  line-height: 0.98;
}

.hero h1 > span {
  display: block;
  font-size: clamp(4.4rem, 9.2vw, 8.6rem);
}

.hero h1 small {
  display: block;
  max-width: 700px;
  margin-top: 1.4rem;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: clamp(1.25rem, 2.15vw, 2.15rem);
  font-weight: 650;
  letter-spacing: -0.025em;
  line-height: 1.28;
}

.hero-lead {
  max-width: 700px;
  margin: 2rem 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: clamp(1.05rem, 1.45vw, 1.28rem);
  line-height: 1.9;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  margin-top: 2.2rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 1.2rem;
  min-height: 48px;
  padding: 0.75rem 1.2rem;
  border: 1px solid var(--ink);
  font-size: 0.88rem;
  font-weight: 750;
  text-decoration: none;
  transition: color 160ms ease, background-color 160ms ease, transform 160ms ease;
}

.button:hover {
  color: var(--paper-light);
  background: var(--route);
  border-color: var(--route);
  transform: translateY(-2px);
}

.button-primary {
  color: var(--paper-light);
  background: var(--ink);
}

.button-quiet {
  color: var(--ink);
  background: transparent;
}

.book-facts {
  display: flex;
  gap: clamp(1.3rem, 4vw, 3.5rem);
  margin: 2.8rem 0 0;
}

.book-facts div {
  display: grid;
  grid-template-columns: auto auto;
  gap: 0.45rem;
  align-items: baseline;
}

.book-facts dt {
  font-family: var(--mono);
  font-size: 1.05rem;
  font-weight: 800;
}

.book-facts dd {
  margin: 0;
  color: var(--muted);
  font-size: 0.72rem;
}

.route-card {
  position: relative;
  padding: clamp(2rem, 4vw, 3.5rem);
  color: var(--paper-light);
  background: var(--ink);
  box-shadow: 24px 24px 0 var(--paper-deep);
}

.route-stamp {
  position: absolute;
  top: 1rem;
  right: -1.65rem;
  padding: 0.35rem 0.75rem;
  color: var(--paper-light);
  background: var(--route);
  font-family: var(--mono);
  font-size: 0.58rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  transform: rotate(90deg) translateX(100%);
  transform-origin: right top;
}

.route-caption {
  margin: 0 0 2rem;
  color: rgba(250, 247, 240, 0.6);
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
}

.route-line {
  position: relative;
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.route-line::before {
  position: absolute;
  top: 1rem;
  bottom: 1rem;
  left: 1.05rem;
  width: 1px;
  content: "";
  background: rgba(250, 247, 240, 0.25);
}

.route-line li {
  position: relative;
  display: grid;
  grid-template-columns: 2.1rem 1fr;
  grid-template-rows: auto auto;
  column-gap: 1.2rem;
  padding: 0.9rem 0;
}

.route-index {
  z-index: 1;
  grid-row: 1 / 3;
  align-self: center;
  width: 2.1rem;
  height: 2.1rem;
  color: var(--paper-light);
  border: 1px solid rgba(250, 247, 240, 0.5);
  background: var(--ink);
  font-family: var(--mono);
  font-size: 0.62rem;
  line-height: 2.05rem;
  text-align: center;
}

.route-line li:last-child .route-index {
  border-color: var(--route);
  background: var(--route);
}

.route-line strong {
  font-family: var(--serif);
  font-size: 1.45rem;
}

.route-line small {
  color: rgba(250, 247, 240, 0.58);
  font-size: 0.72rem;
}

.route-question {
  margin: 2rem 0 0;
  padding-top: 1.5rem;
  color: rgba(250, 247, 240, 0.72);
  border-top: 1px solid rgba(250, 247, 240, 0.2);
  font-family: var(--serif);
  font-size: 0.95rem;
  line-height: 1.8;
}

.section-frame {
  max-width: var(--page);
  margin: 0 auto;
  padding: clamp(5rem, 10vw, 9rem) 4vw;
  border-top: 1px solid var(--line-strong);
}

.section-index,
.eyebrow {
  margin: 0;
  color: var(--route);
  font-family: var(--mono);
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.opening-grid {
  display: grid;
  grid-template-columns: minmax(260px, 0.7fr) minmax(0, 1.3fr);
  gap: clamp(3rem, 8vw, 9rem);
  margin-top: 2.5rem;
}

.opening-grid h2,
.section-heading h2,
.download-intro h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.5rem, 5vw, 5rem);
  font-weight: 800;
  letter-spacing: -0.055em;
  line-height: 1.08;
}

.opening-body {
  max-width: 680px;
  font-family: var(--serif);
  font-size: clamp(1.05rem, 1.7vw, 1.32rem);
  line-height: 2;
}

.opening-body p:first-child {
  margin-top: 0;
}

.perspective-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  margin-top: clamp(4rem, 8vw, 7rem);
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line-strong);
}

.perspective-compare > div {
  padding: 2rem clamp(1rem, 3vw, 3rem) 2.3rem 0;
}

.perspective-compare > div + div {
  padding-right: 0;
  padding-left: clamp(1rem, 3vw, 3rem);
  border-left: 1px solid var(--line-strong);
}

.perspective-compare span {
  display: block;
  margin-bottom: 0.9rem;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.66rem;
  letter-spacing: 0.1em;
}

.perspective-compare strong {
  display: block;
  font-size: clamp(1.05rem, 1.8vw, 1.4rem);
}

.perspective-compare p {
  margin: 0.65rem 0 0;
  color: var(--muted);
  font-family: var(--serif);
}

.perspective-compare .is-book-route {
  border-top: 4px solid var(--route);
}

.section-heading {
  display: grid;
  grid-template-columns: 1.25fr 0.75fr;
  gap: clamp(3rem, 9vw, 9rem);
  align-items: end;
}

.section-heading h2 {
  margin-top: 2.5rem;
}

.section-heading > p {
  margin: 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: 1.08rem;
  line-height: 1.9;
}

.chapter-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  margin: clamp(4rem, 8vw, 7rem) 0 0;
  padding: 0;
  border-top: 1px solid var(--line-strong);
  list-style: none;
}

.chapter-grid li {
  border-bottom: 1px solid var(--line);
}

.chapter-grid li:nth-child(odd) {
  border-right: 1px solid var(--line-strong);
}

.chapter-grid a {
  display: grid;
  grid-template-columns: 2.8rem 1fr auto;
  gap: 1rem;
  align-items: start;
  min-height: 126px;
  padding: 1.55rem 1.8rem 1.55rem 0;
  text-decoration: none;
  transition: background-color 160ms ease, padding 160ms ease;
}

.chapter-grid li:nth-child(even) a {
  padding-right: 0;
  padding-left: 1.8rem;
}

.chapter-grid a:hover {
  color: var(--ink);
  background: rgba(255, 255, 255, 0.24);
}

.chapter-list-number {
  color: var(--route);
  font-family: var(--mono);
  font-size: 0.74rem;
  font-weight: 800;
}

.chapter-list-copy {
  display: grid;
  gap: 0.55rem;
}

.chapter-list-copy small {
  color: var(--muted);
  font-size: 0.66rem;
  letter-spacing: 0.06em;
}

.chapter-list-copy strong {
  max-width: 390px;
  font-family: var(--serif);
  font-size: 1.14rem;
  line-height: 1.55;
}

.chapter-arrow {
  color: var(--muted);
  font-size: 1rem;
}

.manifesto {
  position: relative;
  max-width: none;
  padding-right: max(4vw, calc((100vw - var(--page)) / 2 + 4vw));
  padding-left: max(4vw, calc((100vw - var(--page)) / 2 + 4vw));
  color: var(--paper-light);
  border-top: 0;
  background: var(--ink);
}

.manifesto-mark {
  margin: 0;
  color: var(--route);
  font-family: var(--serif);
  font-size: 7rem;
  line-height: 0.5;
}

.manifesto blockquote {
  max-width: 1040px;
  margin: 2rem 0 0;
  font-family: var(--serif);
  font-size: clamp(1.8rem, 4.2vw, 4.1rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.35;
}

.manifesto-source {
  margin: 2.4rem 0 0;
  color: rgba(250, 247, 240, 0.58);
  font-size: 0.75rem;
}

.download-section {
  display: grid;
  grid-template-columns: minmax(280px, 0.8fr) minmax(0, 1.2fr);
  gap: clamp(4rem, 10vw, 10rem);
}

.download-intro h2 {
  margin-top: 2.5rem;
}

.download-intro > p:last-child {
  max-width: 500px;
  margin-top: 2rem;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: 1.05rem;
  line-height: 1.9;
}

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

.download-list a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 128px;
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--line-strong);
  text-decoration: none;
}

.download-list a:hover strong {
  color: var(--route);
}

.download-list span {
  display: grid;
  gap: 0.25rem;
}

.download-list small,
.download-list b {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.65rem;
  font-weight: 500;
  letter-spacing: 0.06em;
}

.download-list strong {
  font-family: var(--serif);
  font-size: 1.5rem;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 2rem;
  padding: 3.2rem 4vw;
  color: rgba(250, 247, 240, 0.62);
  background: #0f222d;
  font-size: 0.72rem;
}

.site-footer p {
  margin: 0.25rem 0;
}

.site-footer .footer-title {
  color: var(--paper-light);
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 700;
}

.site-footer a {
  color: inherit;
}

.footer-meta {
  text-align: right;
}

/* Reading pages */
.reading-shell {
  display: grid;
  grid-template-columns: minmax(230px, 310px) minmax(0, 1fr);
  max-width: var(--page);
  margin: 0 auto;
  padding: 0 4vw;
}

.book-rail {
  position: sticky;
  top: 74px;
  align-self: start;
  max-height: calc(100vh - 74px);
  padding: 3rem 2.3rem 3rem 0;
  overflow: auto;
  border-right: 1px solid var(--line);
}

.rail-kicker {
  margin: 0;
  color: var(--route);
  font-family: var(--mono);
  font-size: 0.62rem;
  font-weight: 800;
  letter-spacing: 0.08em;
}

.rail-title {
  margin: 0.45rem 0 1.5rem;
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 800;
}

.rail-list {
  display: grid;
  gap: 0.1rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.rail-list a {
  display: grid;
  gap: 0.15rem;
  padding: 0.58rem 0.5rem 0.58rem 0.8rem;
  color: var(--muted);
  border-left: 2px solid transparent;
  font-family: var(--serif);
  font-size: 0.79rem;
  line-height: 1.45;
  text-decoration: none;
}

.rail-list a span {
  font-family: var(--sans);
  font-size: 0.58rem;
}

.rail-list a:hover,
.rail-list .is-current a {
  color: var(--ink);
  border-left-color: var(--route);
  background: rgba(255, 255, 255, 0.28);
}

.chapter {
  width: 100%;
  max-width: calc(var(--reading) + 10vw);
  min-width: 0;
  margin: 0 auto;
  padding: 2.4rem 5vw 6rem;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.64rem;
}

.breadcrumb a {
  text-decoration: none;
}

.chapter-header {
  margin: clamp(3rem, 7vw, 6rem) 0 4rem;
  padding-bottom: 3rem;
  border-bottom: 1px solid var(--line-strong);
}

.chapter-number {
  margin: 1.7rem 0 0.25rem;
  color: var(--route);
  font-family: var(--serif);
  font-size: 1.05rem;
  font-weight: 800;
}

.chapter-header h1 {
  max-width: 790px;
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.7rem, 6.3vw, 5.6rem);
  font-weight: 800;
  letter-spacing: -0.06em;
  line-height: 1.12;
}

.chapter-deck {
  max-width: 650px;
  margin: 1.6rem 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: 1.05rem;
  line-height: 1.85;
}

.mobile-contents {
  display: none;
}

.prose {
  max-width: var(--reading);
  margin: 0 auto;
  color: #243b48;
  font-family: var(--serif);
  font-size: clamp(1.06rem, 1.4vw, 1.18rem);
  line-height: 2.02;
}

.prose > p:first-child {
  margin-top: 0;
}

.prose p {
  margin: 1.45em 0;
}

.prose h2 {
  margin: 3.2em 0 1.1em;
  padding-top: 0.8em;
  color: var(--ink);
  border-top: 1px solid var(--line);
  font-family: var(--serif);
  font-size: clamp(1.65rem, 3vw, 2.25rem);
  letter-spacing: -0.035em;
  line-height: 1.35;
}

.prose h3 {
  margin: 2.5em 0 0.9em;
  color: var(--ink);
  font-size: 1.25rem;
  line-height: 1.45;
}

.prose a {
  color: var(--route-dark);
}

.prose blockquote {
  margin: 2em 0;
  padding: 0.1rem 0 0.1rem 1.4rem;
  color: var(--ink-soft);
  border-left: 4px solid var(--route);
  font-style: normal;
}

.prose blockquote p {
  margin: 0.75em 0;
}

.prose ul,
.prose ol {
  padding-left: 1.3em;
}

.prose li {
  margin: 0.65em 0;
  padding-left: 0.3em;
}

.prose hr {
  width: 90px;
  margin: 4rem auto;
  border: 0;
  border-top: 4px solid var(--route);
}

.prose code {
  padding: 0.12em 0.3em;
  background: var(--paper-deep);
  font-family: var(--mono);
  font-size: 0.85em;
}

.prose pre {
  padding: 1.2rem;
  overflow: auto;
  color: var(--paper-light);
  background: var(--ink);
  line-height: 1.6;
}

.prose pre code {
  padding: 0;
  background: transparent;
}

.prose table {
  display: block;
  width: 100%;
  margin: 2rem 0;
  overflow-x: auto;
  border-collapse: collapse;
  font-family: var(--sans);
  font-size: 0.82rem;
}

.prose th,
.prose td {
  padding: 0.65rem 0.8rem;
  border: 1px solid var(--line);
  text-align: left;
}

.source-note {
  max-width: var(--reading);
  margin: 5rem auto 0;
  padding-top: 1.2rem;
  color: var(--muted);
  border-top: 1px solid var(--line);
  font-size: 0.7rem;
}

.chapter-pagination {
  display: grid;
  grid-template-columns: 1fr 1fr;
  max-width: var(--reading);
  margin: 2rem auto 0;
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line-strong);
}

.chapter-pagination a {
  display: grid;
  gap: 0.4rem;
  min-height: 130px;
  padding: 1.5rem 1.3rem 1.5rem 0;
  font-family: var(--serif);
  font-size: 1rem;
  line-height: 1.5;
  text-decoration: none;
}

.chapter-pagination a + a {
  padding-right: 0;
  padding-left: 1.3rem;
  border-left: 1px solid var(--line-strong);
  text-align: right;
}

.chapter-pagination a span {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.6rem;
  letter-spacing: 0.08em;
}

/* Search landing page */
.answer-page {
  max-width: 1040px;
  margin: 0 auto;
  padding: 2.4rem 4vw 7rem;
}

.answer-header {
  margin: clamp(4rem, 9vw, 8rem) 0 3rem;
}

.answer-header h1 {
  margin: 1.4rem 0 0;
  font-family: var(--serif);
  font-size: clamp(4rem, 10vw, 8.5rem);
  font-weight: 800;
  letter-spacing: -0.07em;
  line-height: 0.98;
}

.answer-subtitle {
  max-width: 760px;
  margin: 1.5rem 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: clamp(1.35rem, 3vw, 2.15rem);
  line-height: 1.5;
}

.direct-answer {
  position: relative;
  max-width: 860px;
  margin: 0 0 5rem;
  padding: clamp(1.7rem, 4vw, 3rem);
  color: var(--paper-light);
  background: var(--ink);
}

.direct-answer::after {
  position: absolute;
  right: -12px;
  bottom: -12px;
  width: 80px;
  height: 80px;
  content: "";
  border-right: 12px solid var(--route);
  border-bottom: 12px solid var(--route);
}

.direct-label {
  margin: 0 0 0.8rem;
  color: #d98874;
  font-family: var(--mono);
  font-size: 0.66rem;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.direct-answer p:last-child {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(1.15rem, 2.2vw, 1.55rem);
  line-height: 1.8;
}

.answer-body {
  margin: 0;
}

.answer-callout {
  margin: 3rem -3rem;
  padding: 2.2rem 3rem;
  color: var(--ink);
  border-top: 1px solid var(--line-strong);
  border-bottom: 1px solid var(--line-strong);
  background: rgba(255, 255, 255, 0.26);
  font-size: 1.15rem;
}

.answer-callout p {
  margin: 0;
}

.answer-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  max-width: 860px;
  margin-top: 6rem;
  padding-top: 2.5rem;
  border-top: 4px solid var(--route);
}

.answer-cta p {
  display: grid;
  gap: 0.4rem;
  margin: 0;
}

.answer-cta p span {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.64rem;
  letter-spacing: 0.08em;
}

.answer-cta p strong {
  font-family: var(--serif);
  font-size: 1.25rem;
}

.not-found {
  max-width: 900px;
  min-height: 65vh;
  margin: 0 auto;
  padding: 14vh 4vw;
}

.not-found h1 {
  max-width: 700px;
  margin: 1.2rem 0;
  font-family: var(--serif);
  font-size: clamp(3rem, 8vw, 7rem);
  letter-spacing: -0.06em;
  line-height: 1.05;
}

.not-found p:not(.eyebrow) {
  margin-bottom: 2rem;
  color: var(--muted);
}

@media (max-width: 980px) {
  .hero {
    grid-template-columns: 1fr;
    min-height: 0;
  }

  .route-card {
    max-width: 650px;
  }

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

  .section-heading > p {
    max-width: 650px;
  }

  .reading-shell {
    display: block;
  }

  .book-rail {
    display: none;
  }

  .mobile-contents {
    display: block;
    max-width: var(--reading);
    margin: -1.5rem auto 3.5rem;
    border-top: 1px solid var(--line-strong);
    border-bottom: 1px solid var(--line-strong);
  }

  .mobile-contents summary {
    padding: 0.9rem 0;
    cursor: pointer;
    font-size: 0.78rem;
    font-weight: 750;
  }

  .mobile-contents ol {
    padding: 0 0 1rem 1.3rem;
    font-family: var(--serif);
    font-size: 0.82rem;
  }

  .mobile-contents li {
    margin: 0.5rem 0;
  }
}

@media (max-width: 680px) {
  .site-header {
    min-height: 62px;
  }

  .nav-toggle {
    display: block;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    right: 0;
    left: 0;
    display: none;
    align-items: stretch;
    padding: 1rem 4vw 1.4rem;
    border-bottom: 1px solid var(--line-strong);
    background: var(--paper);
  }

  .site-nav.is-open {
    display: grid;
  }

  .site-nav a {
    padding: 0.55rem 0;
  }

  .hero {
    gap: 4rem;
    padding-top: 3.2rem;
    padding-bottom: 5rem;
  }

  .edition-line {
    display: grid;
    gap: 0.35rem;
  }

  .hero h1 > span {
    font-size: clamp(3.7rem, 19vw, 5.6rem);
  }

  .hero-actions,
  .hero-actions .button {
    width: 100%;
  }

  .book-facts {
    justify-content: space-between;
  }

  .book-facts div {
    display: block;
  }

  .book-facts dd {
    margin-top: 0.15rem;
  }

  .route-card {
    margin-right: 12px;
    padding: 2rem 1.5rem;
    box-shadow: 12px 12px 0 var(--paper-deep);
  }

  .route-stamp {
    display: none;
  }

  .perspective-compare,
  .chapter-grid {
    grid-template-columns: 1fr;
  }

  .perspective-compare > div + div {
    padding-left: 0;
    border-top: 1px solid var(--line-strong);
    border-left: 0;
  }

  .chapter-grid li:nth-child(odd) {
    border-right: 0;
  }

  .chapter-grid li:nth-child(even) a {
    padding-left: 0;
  }

  .manifesto blockquote {
    font-size: 1.8rem;
  }

  .download-list a {
    min-height: 105px;
  }

  .download-list b {
    max-width: 100px;
    text-align: right;
  }

  .site-footer {
    display: grid;
  }

  .footer-meta {
    text-align: left;
  }

  .chapter {
    padding-right: 0;
    padding-left: 0;
  }

  .chapter > * {
    margin-right: 4vw;
    margin-left: 4vw;
  }

  .chapter-header h1 {
    font-size: clamp(2.5rem, 12vw, 4.2rem);
  }

  .chapter-pagination {
    grid-template-columns: 1fr;
  }

  .chapter-pagination a + a {
    border-top: 1px solid var(--line-strong);
    border-left: 0;
  }

  .answer-header h1 {
    font-size: clamp(4rem, 22vw, 7rem);
  }

  .answer-callout {
    margin-right: 0;
    margin-left: 0;
    padding: 1.5rem;
  }

  .answer-cta {
    display: grid;
  }

  .answer-cta .button {
    width: 100%;
  }
}

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

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