:root {
  --terrain-sand: #a89474;
  --terrain-sand-light: #c9b899;
  --terrain-ink: #2c2824;
  --terrain-ink-soft: #3a342e;
  --terrain-line: rgba(44, 40, 36, 0.34);
  --terrain-paper-line: rgba(201, 184, 153, 0.3);
  --terrain-display: "Noto Serif SC", "Songti SC", serif;
  --terrain-sans: "Noto Sans SC", sans-serif;
  --terrain-mono: "IBM Plex Mono", "JetBrains Mono", monospace;
  --terrain-gutter: clamp(1.2rem, 4vw, 4.5rem);
  --terrain-ease: cubic-bezier(0.16, 1, 0.3, 1);
}

html[data-experience="terrain"] { color-scheme: light; background: var(--terrain-sand); scroll-behavior: smooth; }
html[data-experience="terrain"] body {
  overflow-x: hidden;
  overflow-y: auto;
  background: var(--terrain-sand);
  color: var(--terrain-ink);
  font-family: var(--terrain-sans);
}
html[data-experience="terrain"] ::selection { background: var(--terrain-ink); color: var(--terrain-sand-light); }
html[data-experience="terrain"] a:focus-visible,
html[data-experience="terrain"] button:focus-visible { outline: 2px solid currentColor; outline-offset: 4px; }
html[data-experience="terrain"] .style-switcher {
  border-color: rgba(44, 40, 36, 0.42);
  background: rgba(168, 148, 116, 0.9);
  box-shadow: 0 14px 44px rgba(44, 40, 36, 0.16);
}
html[data-experience="terrain"] .style-switcher__signal { background: var(--terrain-ink); }
html[data-experience="terrain"] .style-switcher button { color: rgba(44, 40, 36, 0.62); }
html[data-experience="terrain"] .style-switcher button:hover { color: var(--terrain-ink); }
html[data-experience="terrain"] .style-switcher button[aria-pressed="true"] { background: var(--terrain-ink); color: var(--terrain-sand-light); }

.terrain-experience { position: relative; min-height: 100vh; isolation: isolate; background: var(--terrain-sand); }
.terrain-noise {
  position: fixed;
  z-index: 80;
  inset: 0;
  pointer-events: none;
  opacity: 0.18;
  mix-blend-mode: multiply;
  background-image:
    linear-gradient(90deg, rgba(44, 40, 36, 0.035) 1px, transparent 1px),
    linear-gradient(rgba(44, 40, 36, 0.028) 1px, transparent 1px);
  background-size: 7px 7px;
}
.terrain-cursor {
  position: fixed;
  z-index: 4;
  left: -200px;
  top: -200px;
  width: 56px;
  height: 56px;
  border: 1px solid var(--terrain-ink);
  border-radius: 50%;
  pointer-events: none;
  transform: translate3d(-50%, -50%, 0);
  transition: width 250ms var(--terrain-ease), height 250ms var(--terrain-ease), opacity 250ms ease;
}
.terrain-cursor::before,
.terrain-cursor::after { content: ""; position: absolute; background: var(--terrain-ink); }
.terrain-cursor::before { left: 50%; top: -7px; bottom: -7px; width: 1px; }
.terrain-cursor::after { top: 50%; left: -7px; right: -7px; height: 1px; }
.terrain-cursor.is-over { width: 88px; height: 88px; }

.terrain-header {
  position: fixed;
  z-index: 120;
  top: 5.25rem;
  left: var(--terrain-gutter);
  right: var(--terrain-gutter);
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  color: currentColor;
  font-family: var(--terrain-mono);
  font-size: 0.58rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  pointer-events: none;
  transition: color 350ms ease;
}
.terrain-header a { width: max-content; color: inherit; text-decoration: none; pointer-events: auto; }
.terrain-header__status { display: flex; align-items: center; gap: 0.8rem; }
.terrain-header__status i { width: 2.6rem; height: 1px; background: currentColor; opacity: 0.55; }
.terrain-header > p { justify-self: end; margin: 0; }
.terrain-header.is-inverse { color: var(--terrain-sand-light); }

.terrain-main { position: relative; z-index: 1; }
.terrain-chapter { position: relative; min-height: 100vh; scroll-margin-top: 0; overflow: clip; }
.terrain-kicker,
.terrain-coordinate,
.terrain-index,
.terrain-label {
  margin: 0;
  font-family: var(--terrain-mono);
  font-size: 0.6rem;
  letter-spacing: 0.15em;
  line-height: 1.5;
  text-transform: uppercase;
}
.terrain-section-head { display: grid; grid-template-columns: 9rem 1fr; gap: clamp(1.5rem, 4vw, 5rem); align-items: start; }
.terrain-section-head h2 {
  max-width: 1100px;
  margin: 0;
  font-family: var(--terrain-display);
  font-size: clamp(4.2rem, 9.6vw, 10rem);
  font-weight: 400;
  letter-spacing: -0.075em;
  line-height: 0.86;
}
.terrain-section-head h2 em { font-style: italic; font-weight: 400; }
.terrain-section-head__meta { display: flex; justify-content: space-between; grid-column: 2; padding-top: 1rem; border-top: 1px solid currentColor; }
.terrain-section-head__meta p { max-width: 34rem; margin: 0; font-size: clamp(0.9rem, 1.3vw, 1.15rem); line-height: 1.7; }

/* 00 — prologue */
.terrain-hero { min-height: 112svh; padding: 9.5rem var(--terrain-gutter) 3rem; }
.terrain-hero__topline { display: flex; justify-content: space-between; padding-top: 1.1rem; border-top: 1px solid var(--terrain-line); }
.terrain-hero__title { position: relative; z-index: 3; margin: clamp(4rem, 11vh, 7rem) 0 0; }
.terrain-hero__title span { display: block; font-family: var(--terrain-display); font-size: clamp(6.3rem, 17.5vw, 18rem); font-weight: 400; letter-spacing: -0.095em; line-height: 0.69; }
.terrain-hero__title span:last-child { margin-left: 18vw; font-style: italic; }
.terrain-hero__map {
  position: absolute;
  z-index: 1;
  top: 13%;
  right: -4vw;
  width: min(52vw, 760px);
  color: var(--terrain-ink);
  opacity: 0.72;
  transform: rotate(-7deg);
}
.terrain-hero__map svg { display: block; width: 100%; height: auto; overflow: visible; }
.terrain-hero__map path { fill: none; stroke: currentColor; stroke-width: 1; vector-effect: non-scaling-stroke; }
.terrain-hero__map path:nth-child(2n) { opacity: 0.55; }
.terrain-hero__map circle { fill: var(--terrain-ink); }
.terrain-hero__pin { position: absolute; left: 49%; top: 45%; width: 18px; height: 18px; border: 1px solid currentColor; border-radius: 50%; animation: terrain-pulse 2.8s ease-in-out infinite; }
.terrain-hero__pin::before { content: ""; position: absolute; inset: 5px; border-radius: 50%; background: currentColor; }
.terrain-hero__manifesto { position: absolute; z-index: 3; right: var(--terrain-gutter); bottom: 6.5rem; width: min(35rem, 38vw); }
.terrain-hero__manifesto p { margin: 0 0 2rem; font-family: var(--terrain-display); font-size: clamp(1.7rem, 3vw, 3.4rem); line-height: 1.13; }
.terrain-hero__manifesto footer { display: flex; justify-content: space-between; padding-top: 0.8rem; border-top: 1px solid var(--terrain-line); }
.terrain-scroll-mark { position: absolute; left: var(--terrain-gutter); bottom: 3rem; display: flex; align-items: center; gap: 0.9rem; color: inherit; font-family: var(--terrain-mono); font-size: 0.58rem; letter-spacing: 0.14em; text-decoration: none; }
.terrain-scroll-mark i { display: block; width: 48px; height: 48px; border: 1px solid currentColor; border-radius: 50%; position: relative; }
.terrain-scroll-mark i::before { content: "↓"; position: absolute; inset: 0; display: grid; place-items: center; font-style: normal; font-size: 1rem; }

/* 01 — capability map */
.terrain-map { padding: 10rem var(--terrain-gutter); border-top: 1px solid var(--terrain-line); }
.terrain-map__stage { position: relative; min-height: 780px; margin-top: 6rem; border: 1px solid var(--terrain-line); }
.terrain-map__stage::before,
.terrain-map__stage::after { content: ""; position: absolute; background: var(--terrain-line); pointer-events: none; }
.terrain-map__stage::before { left: 50%; top: 0; bottom: 0; width: 1px; }
.terrain-map__stage::after { top: 50%; left: 0; right: 0; height: 1px; }
.terrain-map__rings { position: absolute; inset: 7% 10%; display: grid; place-items: center; }
.terrain-map__rings span { position: absolute; border: 1px solid var(--terrain-line); border-radius: 46% 54% 41% 59% / 55% 43% 57% 45%; }
.terrain-map__rings span:nth-child(1) { width: 82%; height: 86%; transform: rotate(5deg); }
.terrain-map__rings span:nth-child(2) { width: 65%; height: 69%; transform: rotate(-8deg); }
.terrain-map__rings span:nth-child(3) { width: 47%; height: 50%; transform: rotate(13deg); }
.terrain-map__rings span:nth-child(4) { width: 28%; height: 31%; transform: rotate(-5deg); }
.terrain-map__center { position: absolute; z-index: 2; inset: 50% auto auto 50%; width: 10rem; transform: translate(-50%, -50%); text-align: center; }
.terrain-map__center strong { display: block; font-family: var(--terrain-display); font-size: 2.2rem; font-weight: 400; }
.terrain-map__center small { font-family: var(--terrain-mono); font-size: 0.55rem; letter-spacing: 0.12em; }
.terrain-node {
  position: absolute;
  z-index: 3;
  display: flex;
  width: clamp(11rem, 18vw, 18rem);
  min-height: 8rem;
  padding: 1rem;
  flex-direction: column;
  justify-content: space-between;
  border: 1px solid var(--terrain-ink);
  background: var(--terrain-sand);
  color: var(--terrain-ink);
  text-align: left;
  cursor: pointer;
  transition: background 250ms ease, color 250ms ease, transform 250ms var(--terrain-ease);
}
.terrain-node:hover,
.terrain-node.is-active { background: var(--terrain-ink); color: var(--terrain-sand-light); transform: translateY(-5px); }
.terrain-node span { font-family: var(--terrain-mono); font-size: 0.55rem; letter-spacing: 0.12em; }
.terrain-node strong { font-family: var(--terrain-display); font-size: clamp(1.7rem, 2.5vw, 2.8rem); font-weight: 400; }
.terrain-node:nth-of-type(1) { left: 4%; top: 12%; }
.terrain-node:nth-of-type(2) { right: 4%; top: 18%; }
.terrain-node:nth-of-type(3) { left: 9%; bottom: 12%; }
.terrain-node:nth-of-type(4) { right: 8%; bottom: 8%; }
.terrain-map__caption { position: absolute; z-index: 4; left: 50%; bottom: 2rem; width: min(28rem, 42%); margin: 0; transform: translateX(-50%); font-family: var(--terrain-display); font-size: 1.2rem; line-height: 1.5; text-align: center; }

/* 02 — route */
.terrain-route { padding: 11rem var(--terrain-gutter); color: var(--terrain-sand-light); background: var(--terrain-ink); }
.terrain-route__line { position: relative; margin-top: 8rem; }
.terrain-route__line::before { content: ""; position: absolute; left: 18%; top: 0; bottom: 0; width: 1px; background: var(--terrain-paper-line); }
.terrain-stop { position: relative; display: grid; grid-template-columns: 18% 24% 1fr; gap: 2rem; padding: 1.65rem 0; border-bottom: 1px solid var(--terrain-paper-line); }
.terrain-stop::before { content: ""; position: absolute; left: calc(18% - 4px); top: 2.25rem; width: 9px; height: 9px; border-radius: 50%; background: var(--terrain-sand-light); }
.terrain-stop time,
.terrain-stop > span { font-family: var(--terrain-mono); font-size: 0.62rem; letter-spacing: 0.12em; }
.terrain-stop h3 { margin: 0; font-family: var(--terrain-display); font-size: clamp(2rem, 4vw, 4rem); font-weight: 400; line-height: 1; }
.terrain-stop p { max-width: 38rem; margin: 0; font-size: 0.9rem; line-height: 1.7; }
.terrain-route__quote { width: min(76rem, 92%); margin: 9rem auto 0; font-family: var(--terrain-display); font-size: clamp(2.4rem, 5vw, 5.6rem); line-height: 1.05; text-align: center; }

/* 03 — strata */
.terrain-strata { padding: 11rem var(--terrain-gutter); }
.terrain-strata__stack { margin-top: 7rem; border-top: 1px solid var(--terrain-line); }
.terrain-layer {
  display: grid;
  grid-template-columns: 7rem minmax(14rem, 0.7fr) 1fr;
  gap: clamp(1rem, 4vw, 4rem);
  min-height: 12rem;
  padding: 2rem 0;
  align-items: start;
  border-bottom: 1px solid var(--terrain-line);
  transition: padding 350ms var(--terrain-ease), background 350ms ease;
}
.terrain-layer:hover { padding-inline: 1.3rem; background: rgba(44, 40, 36, 0.06); }
.terrain-layer > span { font-family: var(--terrain-mono); font-size: 0.6rem; letter-spacing: 0.14em; }
.terrain-layer h3 { margin: 0; font-family: var(--terrain-display); font-size: clamp(2.4rem, 4.2vw, 4.6rem); font-weight: 400; line-height: 0.92; }
.terrain-layer div { display: grid; grid-template-columns: 1fr 1fr; gap: 2rem; }
.terrain-layer p { max-width: 32rem; margin: 0; font-size: 0.95rem; line-height: 1.75; }
.terrain-layer small { font-family: var(--terrain-mono); font-size: 0.58rem; letter-spacing: 0.1em; line-height: 1.8; }

/* 04 — landmarks */
.terrain-landmarks { padding: 11rem 0 8rem; color: var(--terrain-sand-light); background: var(--terrain-ink); }
.terrain-landmarks .terrain-section-head { padding-inline: var(--terrain-gutter); }
.terrain-landmarks__controls { display: flex; justify-content: flex-end; gap: 0.5rem; margin: 3rem var(--terrain-gutter) 1.2rem; }
.terrain-landmarks__controls button { min-width: 4.7rem; min-height: 44px; border: 1px solid var(--terrain-paper-line); background: transparent; color: inherit; font-family: var(--terrain-mono); font-size: 0.56rem; letter-spacing: 0.12em; cursor: pointer; }
.terrain-landmarks__controls button:hover { background: var(--terrain-sand-light); color: var(--terrain-ink); }
.terrain-ledger { display: grid; grid-auto-flow: column; grid-auto-columns: minmax(360px, 38vw); gap: 1px; overflow-x: auto; overscroll-behavior-inline: contain; scroll-snap-type: x mandatory; scrollbar-width: none; background: var(--terrain-paper-line); }
.terrain-ledger::-webkit-scrollbar { display: none; }
.terrain-site { position: relative; min-height: 34rem; padding: 2rem; overflow: hidden; scroll-snap-align: start; background: var(--terrain-ink); }
.terrain-site::before { content: attr(data-site); position: absolute; right: -0.04em; bottom: -0.24em; color: rgba(201, 184, 153, 0.055); font-family: var(--terrain-display); font-size: 18rem; line-height: 1; }
.terrain-site header { position: relative; z-index: 1; display: flex; justify-content: space-between; padding-bottom: 1rem; border-bottom: 1px solid var(--terrain-paper-line); font-family: var(--terrain-mono); font-size: 0.55rem; letter-spacing: 0.12em; }
.terrain-site h3 { position: relative; z-index: 1; margin: 5rem 0 0; font-family: var(--terrain-display); font-size: clamp(2.6rem, 4vw, 4.7rem); font-weight: 400; line-height: 0.92; }
.terrain-site__type { position: relative; z-index: 1; font-family: var(--terrain-mono); font-size: 0.58rem; letter-spacing: 0.12em; }
.terrain-site__body { position: absolute; z-index: 1; left: 2rem; right: 2rem; bottom: 2rem; }
.terrain-site__body p { max-width: 32rem; line-height: 1.7; }
.terrain-site__body ul { display: flex; flex-wrap: wrap; gap: 0.45rem; margin: 1.4rem 0 0; padding: 0; list-style: none; }
.terrain-site__body li { padding: 0.45rem 0.65rem; border: 1px solid var(--terrain-paper-line); font-family: var(--terrain-mono); font-size: 0.52rem; letter-spacing: 0.08em; }

/* 05 — elevation */
.terrain-elevation { min-height: 125vh; padding: 11rem var(--terrain-gutter); }
.terrain-elevation__mountain { position: absolute; left: 0; right: 0; bottom: 0; height: 64%; pointer-events: none; }
.terrain-elevation__mountain svg { width: 100%; height: 100%; }
.terrain-elevation__mountain path { fill: none; stroke: var(--terrain-line); stroke-width: 1; vector-effect: non-scaling-stroke; }
.terrain-elevation__grid { position: relative; z-index: 2; display: grid; grid-template-columns: repeat(3, 1fr); margin-top: 9rem; border-top: 1px solid var(--terrain-line); border-bottom: 1px solid var(--terrain-line); }
.terrain-altitude { min-height: 25rem; padding: 2rem; border-right: 1px solid var(--terrain-line); }
.terrain-altitude:last-child { border-right: 0; }
.terrain-altitude span { font-family: var(--terrain-mono); font-size: 0.58rem; letter-spacing: 0.13em; }
.terrain-altitude strong { display: block; margin-top: 4rem; font-family: var(--terrain-display); font-size: clamp(4rem, 8vw, 8.4rem); font-weight: 400; letter-spacing: -0.07em; line-height: 0.8; }
.terrain-altitude p { max-width: 19rem; margin-top: 2.5rem; line-height: 1.65; }

/* 06 — open boundary */
.terrain-finale { min-height: 115svh; padding: 9rem var(--terrain-gutter) 3rem; color: var(--terrain-sand-light); background: var(--terrain-ink); }
.terrain-finale__portrait { position: absolute; inset: 0 0 0 49%; overflow: hidden; }
.terrain-finale__portrait img { width: 100%; height: 100%; object-fit: cover; object-position: center 18%; filter: grayscale(1) sepia(0.28) contrast(1.2); opacity: 0.54; mix-blend-mode: luminosity; }
.terrain-finale__portrait::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, var(--terrain-ink), transparent 55%), linear-gradient(0deg, var(--terrain-ink), transparent 40%); }
.terrain-finale__copy { position: relative; z-index: 2; display: flex; min-height: calc(115svh - 12rem); flex-direction: column; justify-content: space-between; }
.terrain-finale h2 { max-width: 9ch; margin: 6rem 0; font-family: var(--terrain-display); font-size: clamp(5rem, 12vw, 13rem); font-weight: 400; letter-spacing: -0.08em; line-height: 0.78; }
.terrain-finale h2 em { display: block; margin-left: 1.1em; font-weight: 400; }
.terrain-finale__footer { display: grid; grid-template-columns: 1fr 1fr; align-items: end; gap: 2rem; padding-top: 1.5rem; border-top: 1px solid var(--terrain-paper-line); }
.terrain-finale__footer p { max-width: 32rem; margin: 0; font-family: var(--terrain-display); font-size: clamp(1.2rem, 2vw, 2rem); line-height: 1.35; }
.terrain-finale__actions { display: flex; justify-content: flex-end; gap: 0.7rem; }
.terrain-finale__actions button { min-height: 48px; padding: 0 1.2rem; border: 1px solid var(--terrain-paper-line); background: transparent; color: inherit; font-family: var(--terrain-mono); font-size: 0.56rem; letter-spacing: 0.1em; cursor: pointer; }
.terrain-finale__actions button:hover { background: var(--terrain-sand-light); color: var(--terrain-ink); }

.terrain-rail { position: fixed; z-index: 110; top: 50%; right: 1rem; display: grid; gap: 0.15rem; transform: translateY(-50%); }
.terrain-rail a { display: grid; width: 40px; min-height: 40px; place-items: center; border: 1px solid transparent; color: currentColor; font-family: var(--terrain-mono); font-size: 0.52rem; text-decoration: none; opacity: 0.48; }
.terrain-rail a:hover,
.terrain-rail a[aria-current="page"] { border-color: currentColor; opacity: 1; }
.terrain-rail.is-inverse { color: var(--terrain-sand-light); }
.terrain-progress { position: fixed; z-index: 115; left: 0; right: 0; bottom: 0; height: 3px; background: rgba(44, 40, 36, 0.16); }
.terrain-progress span { display: block; width: 0; height: 100%; background: currentColor; transform-origin: left center; }
.terrain-progress.is-inverse { color: var(--terrain-sand-light); background: rgba(201, 184, 153, 0.18); }

.terrain-chapter [data-terrain-reveal] { opacity: 0; transform: translateY(34px); transition: opacity 900ms ease, transform 900ms var(--terrain-ease); }
.terrain-chapter.is-visible [data-terrain-reveal] { opacity: 1; transform: none; }
.terrain-chapter.is-visible [data-terrain-reveal]:nth-child(2) { transition-delay: 100ms; }
.terrain-chapter.is-visible [data-terrain-reveal]:nth-child(3) { transition-delay: 180ms; }

@keyframes terrain-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(44, 40, 36, 0.28); }
  50% { box-shadow: 0 0 0 18px rgba(44, 40, 36, 0); }
}

@media (max-width: 980px) {
  .terrain-section-head { grid-template-columns: 5rem 1fr; }
  .terrain-map__stage { min-height: 680px; }
  .terrain-node { width: 14rem; }
  .terrain-stop { grid-template-columns: 16% 28% 1fr; }
  .terrain-route__line::before { left: 16%; }
  .terrain-stop::before { left: calc(16% - 4px); }
  .terrain-elevation__grid { grid-template-columns: 1fr; }
  .terrain-altitude { min-height: auto; border-right: 0; border-bottom: 1px solid var(--terrain-line); }
  .terrain-altitude:last-child { border-bottom: 0; }
}

@media (max-width: 767px) {
  :root { --terrain-gutter: 1.1rem; }
  html[data-experience="terrain"] .style-switcher { right: max(0.6rem, env(safe-area-inset-right)); width: auto; }
  html[data-experience="terrain"] .style-switcher button { flex: 1; padding-inline: 0.45rem; }
  .terrain-cursor { display: none; }
  .terrain-header { top: 4.9rem; left: var(--terrain-gutter); right: var(--terrain-gutter); grid-template-columns: 1fr auto; }
  .terrain-header__status { justify-self: end; }
  .terrain-header > p { display: none; }
  .terrain-chapter { min-height: auto; }
  .terrain-section-head { display: block; }
  .terrain-section-head h2 { margin-top: 1.5rem; font-size: clamp(3.7rem, 19vw, 6rem); }
  .terrain-section-head__meta { display: block; margin-top: 2rem; }
  .terrain-section-head__meta p { margin-top: 1rem; }
  .terrain-hero { min-height: 105svh; padding-top: 8.5rem; }
  .terrain-hero__topline { font-size: 0.48rem; }
  .terrain-hero__title { margin-top: 7.5rem; }
  .terrain-hero__title span { font-size: clamp(5.4rem, 30vw, 8.6rem); line-height: 0.72; }
  .terrain-hero__title span:last-child { margin-left: 9vw; }
  .terrain-hero__map { top: 23%; right: -35%; width: 110vw; opacity: 0.42; }
  .terrain-hero__manifesto { right: var(--terrain-gutter); bottom: 7.2rem; width: calc(100% - 2.2rem); }
  .terrain-hero__manifesto p { max-width: 12em; font-size: 1.75rem; }
  .terrain-scroll-mark { bottom: 2rem; }
  .terrain-map,
  .terrain-route,
  .terrain-strata,
  .terrain-elevation { padding-block: 7rem; }
  .terrain-map__stage { min-height: 820px; margin-top: 4rem; border-inline: 0; }
  .terrain-map__stage::before { left: 50%; }
  .terrain-map__rings { inset: 21% -28%; }
  .terrain-map__center { top: 48%; }
  .terrain-node { width: calc(50% - 0.75rem); min-height: 7.2rem; padding: 0.75rem; }
  .terrain-node strong { font-size: 1.55rem; }
  .terrain-node:nth-of-type(1) { left: 0; top: 3%; }
  .terrain-node:nth-of-type(2) { right: 0; top: 18%; }
  .terrain-node:nth-of-type(3) { left: 0; bottom: 18%; }
  .terrain-node:nth-of-type(4) { right: 0; bottom: 3%; }
  .terrain-map__caption { bottom: 43%; width: 72%; font-size: 1rem; }
  .terrain-route__line { margin-top: 5rem; }
  .terrain-route__line::before { left: 0.3rem; top: 0; bottom: 0; width: 1px; height: auto; }
  .terrain-stop { grid-template-columns: 1fr; gap: 0.55rem; padding: 1.6rem 0 1.6rem 2rem; }
  .terrain-stop::before { left: 0; top: 1.9rem; }
  .terrain-stop h3 { font-size: 2.5rem; }
  .terrain-route__quote { width: 100%; margin-top: 6rem; text-align: left; }
  .terrain-strata__stack { margin-top: 4rem; }
  .terrain-layer { grid-template-columns: 3rem 1fr; gap: 1rem; min-height: 0; }
  .terrain-layer div { grid-column: 2; grid-template-columns: 1fr; gap: 1rem; }
  .terrain-layer h3 { font-size: 2.8rem; }
  .terrain-landmarks { padding-block: 7rem 5rem; }
  .terrain-landmarks__controls { justify-content: flex-start; margin-top: 2rem; }
  .terrain-ledger { grid-auto-columns: calc(100vw - 2.2rem); }
  .terrain-site { min-height: 32rem; padding: 1.25rem; }
  .terrain-site__body { left: 1.25rem; right: 1.25rem; bottom: 1.25rem; }
  .terrain-elevation { min-height: auto; padding-bottom: 9rem; }
  .terrain-elevation__grid { margin-top: 5rem; }
  .terrain-altitude { min-height: 18rem; padding-inline: 0; }
  .terrain-altitude strong { margin-top: 2.8rem; font-size: 5.6rem; }
  .terrain-finale { min-height: 108svh; padding-top: 8rem; }
  .terrain-finale__portrait { inset: 0; opacity: 0.48; }
  .terrain-finale__portrait::after { background: linear-gradient(0deg, var(--terrain-ink) 4%, rgba(44, 40, 36, 0.4) 62%, var(--terrain-ink)); }
  .terrain-finale__copy { min-height: calc(108svh - 11rem); }
  .terrain-finale h2 { margin-top: 12rem; font-size: clamp(4.8rem, 24vw, 7.8rem); }
  .terrain-finale__footer { grid-template-columns: 1fr; }
  .terrain-finale__actions { justify-content: flex-start; flex-wrap: wrap; }
  .terrain-finale__actions button { min-height: 48px; }
  .terrain-rail { top: auto; left: 50%; right: auto; bottom: 0.75rem; grid-template-columns: repeat(7, 1fr); width: min(calc(100vw - 1.5rem), 370px); padding: 2px; transform: translateX(-50%); background: rgba(168, 148, 116, 0.9); backdrop-filter: blur(10px); }
  .terrain-rail a { width: auto; min-height: 44px; color: var(--terrain-ink); }
  .terrain-rail.is-inverse { background: rgba(44, 40, 36, 0.9); }
  .terrain-rail.is-inverse a { color: var(--terrain-sand-light); }
  .terrain-progress { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  html[data-experience="terrain"] { scroll-behavior: auto; }
  .terrain-hero__pin { animation: none; }
  .terrain-cursor { display: none; }
  .terrain-chapter [data-terrain-reveal] { opacity: 1; transform: none; transition: none; }
  .terrain-node,
  .terrain-layer { transition: none; }
}