:root {
  --color-primary: #1a3d36;
  --color-accent: #b87333;
  --color-bg: #f4f0e8;
  --color-text: #2c2c2c;
  --color-band: #e6ece9;
  --font-serif: "Songti SC", "Noto Serif SC", "STSong", "SimSun", serif;
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --space-xs: 0.5rem;
  --space-sm: 0.875rem;
  --space-md: 1.25rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --size-body: clamp(0.9375rem, 2.8vw, 1.0625rem);
  --size-title: clamp(1.375rem, 4vw, 1.75rem);
  --size-claim: clamp(1.625rem, 5vw, 2.25rem);
  --shell-max: 72.5rem;
  --header-h: 3.25rem;
  --strip-h: 2.75rem;
  --rail-ratio: 38%;
  --content-ratio: 62%;
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: var(--size-body);
  line-height: 1.65;
  overflow-x: hidden;
}

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

a {
  color: var(--color-primary);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  min-height: var(--header-h);
  padding: var(--space-xs) var(--space-md);
  border-bottom: 1px solid color-mix(in srgb, var(--color-primary) 18%, transparent);
  background: color-mix(in srgb, var(--color-bg) 92%, white);
  backdrop-filter: blur(6px);
}

.site-logo {
  flex: 1 1 auto;
  min-width: 0;
  font-family: var(--font-serif);
  font-size: clamp(0.8125rem, 3.2vw, 1rem);
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
  line-height: 1.35;
  word-break: break-all;
}

.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 2.75rem;
  height: 2.75rem;
  padding: 0;
  border: 1px solid color-mix(in srgb, var(--color-primary) 25%, transparent);
  border-radius: 2px;
  background: transparent;
  cursor: pointer;
}

.nav-toggle-bar {
  display: block;
  width: 1.25rem;
  height: 2px;
  margin: 0 auto;
  background: var(--color-primary);
}

.site-nav {
  display: none;
  flex-direction: column;
  width: 100%;
  gap: 0;
  border-top: 1px solid color-mix(in srgb, var(--color-primary) 12%, transparent);
  padding-top: var(--space-xs);
}

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

.site-nav-link {
  position: relative;
  display: block;
  padding: 0.75rem 0.5rem 0.75rem 1rem;
  color: var(--color-text);
  text-decoration: none;
  font-size: 0.9375rem;
}

.nav-indicator {
  position: absolute;
  left: 0;
  top: 0.65rem;
  bottom: 0.65rem;
  width: 3px;
  background: var(--color-accent);
  transform: scaleY(0);
  transform-origin: center top;
  transition: transform 0.25s var(--ease-out);
}

.site-nav-link.is-active .nav-indicator,
.site-nav-link:focus-visible .nav-indicator {
  transform: scaleY(1);
}

.chapter-strip {
  display: flex;
  position: sticky;
  top: var(--header-h);
  z-index: 90;
  background: var(--color-bg);
  border-bottom: 1px solid color-mix(in srgb, var(--color-primary) 14%, transparent);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.chapter-strip-item {
  flex: 1 0 auto;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.5rem 0.75rem;
  font-size: 0.8125rem;
  color: color-mix(in srgb, var(--color-text) 70%, transparent);
  text-decoration: none;
  white-space: nowrap;
}

.chapter-strip-item .chapter-num {
  font-family: var(--font-serif);
  color: var(--color-accent);
}

.chapter-strip-item.is-active {
  color: var(--color-primary);
  font-weight: 600;
}

.chapter-rail {
  display: none;
}

.page-shell {
  width: min(100%, var(--shell-max));
  margin: 0 auto;
  padding: var(--space-md) var(--space-md) var(--space-xl);
}

.content-stream {
  min-width: 0;
}

.section {
  scroll-margin-top: calc(var(--header-h) + var(--strip-h) + 0.5rem);
  padding-bottom: var(--space-xl);
}

.section-title {
  margin: 0 0 var(--space-lg);
  font-family: var(--font-serif);
  font-size: var(--size-title);
  font-weight: 600;
  color: var(--color-primary);
  letter-spacing: 0.04em;
}

.section-hero {
  position: relative;
  padding-top: var(--space-md);
  padding-bottom: var(--space-xl);
}

.hero-copy {
  position: relative;
  max-width: 100%;
  padding: var(--space-lg) 0 var(--space-md);
}

.hero-graphic-wrap {
  margin-top: var(--space-sm);
  pointer-events: none;
  opacity: 0.9;
  overflow: hidden;
}

.hero-graphic {
  display: block;
  width: 100%;
  height: auto;
  max-height: min(42vh, 16rem);
}

.hero-graphic .node-pulse {
  animation: hero-node-breathe 3.6s ease-in-out infinite;
}

.hero-graphic .node-pulse--d1 {
  animation-delay: 0.6s;
}

.hero-graphic .node-pulse--d2 {
  animation-delay: 1.2s;
}

.hero-graphic .node-pulse--d3 {
  animation-delay: 0.3s;
}

@keyframes hero-node-breathe {
  0%,
  100% {
    opacity: 0.35;
  }

  50% {
    opacity: 1;
  }
}

.hero-claim {
  margin: 0 0 var(--space-md);
  font-family: var(--font-serif);
  font-size: var(--size-claim);
  font-weight: 700;
  line-height: 1.25;
  color: var(--color-primary);
}

.hero-spot {
  margin: 0 0 var(--space-sm);
  font-size: clamp(1rem, 3.5vw, 1.125rem);
  color: var(--color-text);
}

.hero-sub {
  margin: 0;
  font-size: clamp(0.875rem, 3vw, 1rem);
  color: color-mix(in srgb, var(--color-text) 82%, transparent);
}

.about-body {
  border-left: 4px solid var(--color-accent);
  padding-left: var(--space-md);
  max-width: 42rem;
}

.about-body p {
  margin: 0;
  text-align: justify;
}

.business-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.biz-segment {
  padding: var(--space-md);
}

.biz-segment--band {
  width: 100%;
  background: var(--color-band);
  border-left: 3px solid var(--color-primary);
}

.biz-segment--right {
  width: min(100%, 92%);
  margin-left: auto;
  text-align: right;
  border-right: 3px solid var(--color-accent);
  padding-right: var(--space-lg);
}

.biz-segment--full {
  width: 100%;
  border-top: 1px solid color-mix(in srgb, var(--color-primary) 20%, transparent);
  border-bottom: 1px solid color-mix(in srgb, var(--color-primary) 20%, transparent);
}

.biz-segment--left {
  width: min(100%, 88%);
  margin-right: auto;
  padding-left: var(--space-lg);
  border-left: 3px solid var(--color-primary);
}

.biz-title {
  margin: 0 0 var(--space-xs);
  font-family: var(--font-serif);
  font-size: clamp(1.125rem, 3.5vw, 1.375rem);
  color: var(--color-primary);
}

.biz-spot {
  margin: 0 0 var(--space-sm);
  font-size: 0.9375rem;
  color: var(--color-accent);
  font-weight: 600;
}

.biz-text {
  margin: 0;
  color: var(--color-text);
}

.reveal-block .reveal-title,
.reveal-block .reveal-text {
  opacity: 0;
  transform: translateY(0.5rem);
  transition: opacity 0.55s var(--ease-out), transform 0.55s var(--ease-out);
}

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

.reveal-block.is-visible .reveal-text {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 80ms;
}

.advantages-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

.advantage-item {
  padding: var(--space-md) var(--space-md) var(--space-md) calc(var(--space-md) + 4px);
  border-left: 4px solid var(--color-accent);
  background: color-mix(in srgb, var(--color-bg) 70%, white);
}

.advantage-title {
  margin: 0 0 var(--space-xs);
  font-family: var(--font-serif);
  font-size: 1.0625rem;
  color: var(--color-primary);
}

.advantage-text {
  margin: 0;
  font-size: 0.9375rem;
}

.site-footer {
  border-top: 1px solid color-mix(in srgb, var(--color-primary) 22%, transparent);
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  font-size: 0.875rem;
  color: color-mix(in srgb, var(--color-text) 75%, transparent);
}

.site-footer p {
  margin: 0 0 var(--space-xs);
}

.footer-beian a {
  color: color-mix(in srgb, var(--color-text) 80%, transparent);
  text-decoration: none;
}

.footer-beian a:hover {
  color: var(--color-accent);
  text-decoration: underline;
}

@media (max-aspect-ratio: 3/4) {
  .hero-copy {
    max-width: 100%;
  }

  .section {
    padding-bottom: calc(var(--space-xl) + 0.5rem);
  }
}

@media (orientation: landscape) and (max-height: 500px) {
  :root {
    --header-h: 2.75rem;
    --strip-h: 2.25rem;
  }

  .section-hero {
    padding-top: var(--space-xs);
    padding-bottom: var(--space-md);
  }

  .hero-copy {
    padding: var(--space-sm) 0 var(--space-xs);
  }

  .hero-graphic {
    max-height: min(28vh, 9rem);
  }

  .hero-claim {
    margin-bottom: var(--space-xs);
    font-size: clamp(1.25rem, 4vw, 1.5rem);
  }

  .section {
    scroll-margin-top: calc(var(--header-h) + var(--strip-h));
    padding-bottom: var(--space-lg);
  }
}

@media (min-width: 768px) {
  .site-nav {
    display: flex !important;
    flex-direction: row;
    flex-wrap: wrap;
    width: auto;
    border-top: none;
    padding-top: 0;
    gap: 0.25rem;
  }

  .nav-toggle {
    display: none;
  }

  .site-nav-link {
    padding: 0.5rem 0.65rem 0.5rem 0.85rem;
  }

  .advantages-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--space-lg);
  }

  .biz-segment--right {
    width: 78%;
  }

  .biz-segment--left {
    width: 74%;
  }
}

@media (min-width: 1100px) {
  .chapter-strip {
    display: none;
  }

  .page-shell {
    display: grid;
    grid-template-columns: var(--rail-ratio) var(--content-ratio);
    gap: var(--space-lg);
    align-items: start;
    padding-top: var(--space-lg);
  }

  .chapter-rail {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    position: sticky;
    top: calc(var(--header-h) + var(--space-md));
    padding-right: var(--space-lg);
  }

  .chapter-rail-item {
    display: flex;
    align-items: baseline;
    gap: var(--space-sm);
    padding: var(--space-sm) 0;
    color: color-mix(in srgb, var(--color-text) 55%, transparent);
    text-decoration: none;
    border-left: 3px solid transparent;
    padding-left: var(--space-sm);
    transition: color 0.2s, border-color 0.2s;
  }

  .chapter-rail-item .chapter-num {
    font-family: var(--font-serif);
    font-size: 1.125rem;
    color: var(--color-accent);
    min-width: 2rem;
  }

  .chapter-rail-item .chapter-label {
    font-size: 0.9375rem;
  }

  .chapter-rail-item.is-active {
    color: var(--color-primary);
    border-left-color: var(--color-accent);
    font-weight: 600;
  }

  .section {
    scroll-margin-top: calc(var(--header-h) + 1rem);
  }

  .about-body {
    max-width: none;
  }
}

@media (min-width: 1440px) {
  .content-stream {
    padding-right: var(--space-md);
  }
}

@media (min-aspect-ratio: 2/1) {
  .about-body {
    max-width: 48rem;
  }

  .hero-graphic {
    max-height: min(36vh, 14rem);
  }
}

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

  .hero-graphic .node-pulse {
    animation: none;
    opacity: 0.85;
  }

  .reveal-block .reveal-title,
  .reveal-block .reveal-text {
    opacity: 1;
    transform: none;
    transition: none;
  }
}