:root {
  --ink: #211d18;
  --muted: #6f675d;
  --paper: #f4f0e8;
  --paper-deep: #e7ded0;
  --soil: #332a22;
  --soil-2: #46392d;
  --clay: #9a6d49;
  --ember: #c4874b;
  --moss: #4d5b45;
  --line: rgba(33, 29, 24, 0.16);
  --white: #fffaf2;
  --shadow: 0 22px 70px rgba(32, 24, 18, 0.18);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family:
    "Noto Serif SC", "Source Han Serif SC", "Songti SC", "SimSun", Georgia, serif;
  line-height: 1.7;
  line-break: strict;
  word-break: normal;
}

body.nav-open {
  overflow: hidden;
}

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

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

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 18px clamp(20px, 4vw, 54px);
  color: var(--white);
  transition:
    background 180ms ease,
    color 180ms ease,
    border-color 180ms ease;
}

.site-header.scrolled {
  color: var(--ink);
  background: rgba(244, 240, 232, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(18px);
}

.brand-mark {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 6px;
  width: 148px;
}

.brand-logo-en,
.brand-logo-cn,
.hero-logo-en,
.hero-logo-cn,
.footer-logo {
  height: auto;
  object-fit: contain;
}

.brand-logo-en {
  width: 138px;
  filter: invert(1) brightness(1.08);
}

.brand-logo-cn {
  width: 58px;
  opacity: 0.72;
  filter: invert(1) brightness(1.08);
}

.site-header.scrolled .brand-logo-en,
.site-header.scrolled .brand-logo-cn {
  filter: none;
}

.nav-links {
  display: flex;
  gap: clamp(14px, 2vw, 30px);
  font-family: Arial, "Microsoft YaHei", sans-serif;
  font-size: 13px;
}

.nav-links a {
  opacity: 0.82;
}

.nav-links a:hover {
  opacity: 1;
}

.menu-toggle {
  display: none;
  min-width: 54px;
  border: 1px solid currentColor;
  border-radius: 999px;
  padding: 8px 14px;
  color: inherit;
  background: transparent;
  font: inherit;
}

.mobile-nav {
  position: fixed;
  inset: 66px 14px auto;
  z-index: 19;
  display: none;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 12px;
  background: rgba(244, 240, 232, 0.96);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.mobile-nav a {
  padding: 12px 14px;
  font-family: Arial, "Microsoft YaHei", sans-serif;
}

.mobile-nav.open {
  display: grid;
}

.hero {
  position: relative;
  display: grid;
  min-height: 100vh;
  padding: 120px clamp(22px, 5vw, 70px) 48px;
  color: var(--white);
  overflow: hidden;
  place-items: end start;
}

.hero::after {
  position: absolute;
  inset: 0;
  content: "";
  background:
    linear-gradient(90deg, rgba(22, 18, 14, 0.86), rgba(22, 18, 14, 0.48) 48%, rgba(22, 18, 14, 0.22)),
    linear-gradient(0deg, rgba(22, 18, 14, 0.74), rgba(22, 18, 14, 0.08) 58%);
}

.hero-media {
  position: absolute;
  inset: 0;
}

.hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-content {
  position: relative;
  z-index: 1;
  width: min(820px, 100%);
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--clay);
  font-family: Arial, "Microsoft YaHei", sans-serif;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.hero .eyebrow {
  color: #d9b88e;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 16px;
  line-height: 1;
}

.hero-logo-en {
  width: min(620px, 82vw);
  filter: invert(1) brightness(1.08);
}

.hero-logo-cn {
  width: min(180px, 38vw);
  margin-bottom: 30px;
  opacity: 0.76;
  filter: invert(1) brightness(1.08);
}

.hero-copy {
  max-width: 680px;
  margin-bottom: 32px;
  font-size: clamp(24px, 3.6vw, 48px);
  line-height: 1.24;
}

.hero-copy span {
  display: block;
  width: max-content;
  max-width: 100%;
  white-space: nowrap;
}

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

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  border: 1px solid currentColor;
  border-radius: 999px;
  padding: 10px 22px;
  font-family: Arial, "Microsoft YaHei", sans-serif;
  font-size: 14px;
  transition:
    transform 160ms ease,
    background 160ms ease,
    color 160ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button.primary {
  color: var(--soil);
  background: var(--paper);
  border-color: var(--paper);
}

.button.ghost {
  color: var(--white);
  background: rgba(255, 250, 242, 0.08);
}

.hero-line {
  position: absolute;
  right: clamp(22px, 5vw, 70px);
  bottom: 48px;
  z-index: 1;
  margin: 0;
  font-size: 16px;
  letter-spacing: 0.18em;
  writing-mode: vertical-rl;
}

.section-shell {
  width: min(1180px, calc(100% - 44px));
  margin: 0 auto;
}

.intro-band {
  padding: 64px 0;
  background: var(--soil);
  color: var(--white);
}

.intro-grid {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: clamp(34px, 6vw, 86px);
  align-items: start;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(30px, 3.4vw, 48px);
  font-weight: 500;
  line-height: 1.16;
  letter-spacing: 0;
  text-wrap: balance;
}

.balanced-title span {
  display: block;
  width: max-content;
  max-width: 100%;
  white-space: nowrap;
}

.prose-lines span {
  display: block;
  width: max-content;
  max-width: 100%;
  white-space: nowrap;
  text-wrap: pretty;
}

.prose-lines .keep-together,
.keep-together {
  display: inline-block;
  white-space: nowrap;
}

h3 {
  margin-bottom: 10px;
  font-size: 22px;
  font-weight: 600;
  line-height: 1.3;
}

.intro-grid p:last-child,
.section-heading p,
.copy-stack p,
.collab-grid p {
  color: var(--muted);
  font-size: 18px;
}

.intro-grid p:last-child {
  color: rgba(255, 250, 242, 0.72);
}

.timeline-section,
#system,
.scenes-section {
  padding: clamp(78px, 9vw, 132px) 0;
}

.section-heading {
  max-width: 800px;
  margin-bottom: 42px;
}

.section-heading.narrow {
  max-width: 760px;
  margin-right: auto;
  margin-left: auto;
  text-align: center;
}

.timeline {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.timeline-card {
  min-height: 280px;
  padding: 28px;
  background: rgba(255, 250, 242, 0.52);
  border: 1px solid var(--line);
}

.timeline-card span,
.scene-strip span {
  display: inline-block;
  margin-bottom: 74px;
  color: var(--clay);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 13px;
  font-weight: 700;
}

.timeline-card p,
.scene-strip p,
.business-grid p,
.system-map p {
  color: var(--muted);
}

.timeline-card.active {
  color: var(--white);
  background: var(--moss);
  border-color: transparent;
}

.timeline-card.active p {
  color: rgba(255, 250, 242, 0.78);
}

.split-section {
  padding: clamp(78px, 10vw, 140px) 0;
  background: var(--paper-deep);
}

.split-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: clamp(34px, 6vw, 84px);
  align-items: center;
}

.quote-panel {
  min-height: 520px;
  display: flex;
  align-items: end;
  padding: clamp(28px, 4vw, 46px);
  color: var(--white);
  background:
    linear-gradient(0deg, rgba(37, 29, 23, 0.9), rgba(37, 29, 23, 0.12)),
    url("assets/soilog-fire-table.png") center / cover;
  box-shadow: var(--shadow);
}

.quote-panel p {
  max-width: 440px;
  margin: 0;
  font-size: clamp(28px, 3.4vw, 46px);
  line-height: 1.22;
}

.copy-stack {
  max-width: 620px;
}

.compare-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-top: 30px;
}

.compare-grid div {
  min-height: 150px;
  padding: 22px;
  background: rgba(255, 250, 242, 0.46);
  border: 1px solid rgba(33, 29, 24, 0.12);
}

.compare-grid strong {
  display: block;
  margin-bottom: 12px;
  color: var(--clay);
  font-family: Arial, "Microsoft YaHei", sans-serif;
}

.pill-tabs {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 18px;
}

.tab-button {
  width: 72px;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ink);
  background: transparent;
  font: inherit;
  cursor: pointer;
}

.tab-button.active {
  color: var(--white);
  background: var(--soil);
  border-color: var(--soil);
}

.tab-panels {
  max-width: 780px;
  min-height: 172px;
  margin: 0 auto 34px;
  padding: 34px;
  text-align: center;
  background: rgba(255, 250, 242, 0.46);
  border: 1px solid var(--line);
}

.tab-panel {
  display: none;
}

.tab-panel.active {
  display: block;
}

.tab-panel p {
  margin: 0 auto;
  max-width: 620px;
  color: var(--muted);
  font-size: 18px;
}

.system-map {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.system-map div {
  min-height: 230px;
  padding: 26px;
  background: var(--paper);
}

.system-map span {
  display: block;
  margin-bottom: 36px;
  color: var(--clay);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.system-map strong {
  display: block;
  margin-bottom: 10px;
  font-size: 24px;
}

.dark-section {
  padding: clamp(82px, 10vw, 142px) 0;
  color: var(--white);
  background: var(--soil);
}

.dark-section .section-heading p {
  color: rgba(255, 250, 242, 0.68);
}

.business-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.business-grid article {
  min-height: 190px;
  padding: 26px;
  background: rgba(255, 250, 242, 0.06);
  border: 1px solid rgba(255, 250, 242, 0.14);
}

.business-grid p {
  color: rgba(255, 250, 242, 0.7);
}

.scene-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(220px, 1fr));
  gap: 14px;
  overflow-x: auto;
  padding-bottom: 10px;
}

.scene-strip article {
  min-height: 300px;
  padding: 24px;
  background: rgba(255, 250, 242, 0.5);
  border: 1px solid var(--line);
}

.collab-section {
  padding: clamp(80px, 9vw, 132px) 0;
  background: var(--paper-deep);
}

.collab-grid {
  display: grid;
  grid-template-columns: 0.95fr 1.05fr;
  gap: clamp(34px, 6vw, 82px);
  align-items: start;
}

.accordion {
  display: grid;
  gap: 10px;
}

.accordion-item {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 20px;
  width: 100%;
  padding: 22px;
  color: var(--ink);
  text-align: left;
  background: rgba(255, 250, 242, 0.5);
  border: 1px solid var(--line);
  cursor: pointer;
}

.accordion-item:hover,
.accordion-item.is-open {
  background: var(--white);
}

.accordion-item span {
  font-size: 20px;
  font-weight: 600;
}

.accordion-item small {
  color: var(--muted);
  font-size: 15px;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 34px clamp(22px, 5vw, 70px);
  color: var(--white);
  background: #18130f;
}

.site-footer p {
  margin: 6px 0 0;
  color: rgba(255, 250, 242, 0.64);
}

.footer-button {
  color: var(--white);
}

.footer-logo {
  width: 132px;
  filter: invert(1) brightness(1.08);
}

@media (max-width: 880px) {
  .nav-links {
    display: none;
  }

  .menu-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .hero {
    min-height: 92vh;
  }

  .hero-line {
    position: relative;
    right: auto;
    bottom: auto;
    margin-top: 40px;
    writing-mode: initial;
  }

  .intro-grid,
  .split-grid,
  .collab-grid {
    grid-template-columns: 1fr;
  }

  .timeline,
  .business-grid,
  .system-map {
    grid-template-columns: 1fr;
  }

  .timeline-card,
  .system-map div {
    min-height: auto;
  }

  .timeline-card span,
  .scene-strip span {
    margin-bottom: 34px;
  }

  .quote-panel {
    min-height: 420px;
  }

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

  .accordion-item {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .site-footer {
    flex-direction: column;
  }

  .balanced-title span {
    width: auto;
    white-space: normal;
  }

  .hero-copy span,
  .prose-lines span {
    width: auto;
    white-space: normal;
  }
}

@media (max-width: 560px) {
  .site-header {
    padding: 14px 18px;
  }

  .brand-mark {
    width: 124px;
  }

  .brand-logo-en {
    width: 116px;
  }

  .brand-logo-cn {
    width: 50px;
  }

  .hero {
    padding: 104px 22px 34px;
  }

  .hero-actions {
    width: 100%;
  }

  .button {
    width: 100%;
  }

  .section-shell {
    width: min(100% - 32px, 1180px);
  }

  .tab-panels {
    padding: 24px 18px;
  }

  .scene-strip {
    grid-template-columns: repeat(4, 78vw);
  }
}