/* MOSINTER layout layer · high-contrast industrial navigation · compact operational footer */
.container {
  margin-inline: auto;
  max-width: var(--container);
  padding-inline: clamp(var(--space-sm), 4vw, var(--space-xl));
  width: 100%;
}

.site-header {
  background: var(--color-paper);
  border-bottom: var(--rule-thin) solid var(--color-rule-2);
  color: var(--color-ink);
  inset: 0 0 auto;
  position: sticky;
  transition:
    background-color 280ms cubic-bezier(0.22, 1, 0.36, 1),
    border-color 280ms ease,
    box-shadow 280ms ease;
  will-change: background-color, box-shadow;
  z-index: 50;
}

.site-header[data-scrolled="true"] {
  background: var(--color-paper);
  box-shadow: 0 8px 24px rgba(34, 20, 10, 0.08);
}

.site-header__inner {
  align-items: center;
  display: flex;
  justify-content: center;
  margin-inline: auto;
  width: 100%;
}

.wordmark {
  color: var(--color-ink);
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 500;
  letter-spacing: -0.06em;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
}

.site-nav {
  align-items: center;
  display: flex;
}

.site-nav > a:not(.button) {
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  text-decoration: none;
  text-transform: uppercase;
  transition: color var(--dur-short) var(--ease-out);
  white-space: nowrap;
}

.site-nav > a:not(.button):hover,
.site-nav > a:not(.button):focus-visible,
.site-nav__dropdown > summary:hover,
.site-nav__dropdown > summary:focus-visible,
.site-nav__dropdown[open] > summary {
  color: var(--color-accent);
}

.site-nav__dropdown {
  position: relative;
}

.site-nav__dropdown > summary {
  align-items: center;
  color: var(--color-ink);
  cursor: pointer;
  display: inline-flex;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  gap: 6px;
  list-style: none;
  text-transform: uppercase;
  white-space: nowrap;
}

.site-nav__dropdown > summary::-webkit-details-marker {
  display: none;
}

.site-nav__dropdown > summary::after {
  border-bottom: 1.5px solid currentColor;
  border-right: 1.5px solid currentColor;
  content: "";
  height: 0.42rem;
  transform: rotate(45deg) translateY(-0.1rem);
  transition: transform var(--dur-short) var(--ease-out);
  width: 0.42rem;
}

.site-nav__dropdown[open] > summary::after {
  transform: rotate(225deg) translate(-0.05rem, -0.05rem);
}

.site-nav__menu {
  background: var(--color-paper);
  border: var(--rule-thin) solid var(--color-rule-2);
  box-shadow: 0 1rem 2.5rem rgba(0, 0, 0, 0.12);
  display: grid;
  left: 0;
  max-width: min(24rem, calc(100vw - 2rem));
  min-width: 20rem;
  padding: var(--space-xs);
  position: absolute;
  top: calc(100% + 1rem);
  width: max-content;
  z-index: 60;
}

.site-nav__dropdown--edge .site-nav__menu {
  left: auto;
  right: 0;
}

.site-nav__menu a {
  color: var(--color-ink);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  padding: 0.7rem 0.8rem;
  text-decoration: none;
  text-transform: none;
  transition:
    background-color var(--dur-short) var(--ease-out),
    color var(--dur-short) var(--ease-out),
    transform var(--dur-short) var(--ease-out);
  white-space: normal;
}

.site-nav__menu a:hover,
.site-nav__menu a:focus-visible {
  background: var(--color-paper-2);
  color: var(--color-accent);
  transform: translateX(3px);
}

.nav-toggle {
  background: transparent;
  border: 0;
  display: none;
  height: 2.75rem;
  padding: var(--space-xs);
  position: relative;
  width: 2.75rem;
}

.nav-toggle > span:not(.sr-only) {
  background: var(--color-ink);
  display: block;
  height: 2px;
  margin-block: var(--space-3xs);
  transform-origin: center;
  transition:
    transform var(--dur-base) var(--ease-out),
    opacity var(--dur-short) var(--ease-out);
  width: 100%;
}

@media (min-width: 120rem) {
  .site-header__inner {
    gap: 42px;
    max-width: 1900px;
    min-height: 82px;
  }

  .site-nav {
    gap: 30px;
  }

  .site-nav > a:not(.button),
  .site-nav__dropdown > summary {
    font-size: 16px;
    font-weight: 600;
  }

  .site-nav > .button {
    font-size: 16px;
    margin-left: 8px;
    min-height: 52px;
    width: 200px;
  }
}

@media (min-width: 120.0625rem) {
  .site-header__inner {
    display: grid;
    gap: 60px;
    grid-template-columns: auto minmax(0, 1fr);
    max-width: 2200px;
    width: calc(100% - 48px);
  }

  .site-nav {
    gap: 40px;
    width: 100%;
  }

  .site-nav > a:not(.button),
  .site-nav__dropdown > summary {
    font-size: 18px;
  }

  .site-nav > .button {
    font-size: 17px;
    margin-left: auto;
  }
}

@media (min-width: 90rem) and (max-width: 119.9375rem) {
  .site-header__inner {
    gap: 30px;
    max-width: 1400px;
    min-height: 76px;
    width: calc(100% - 40px);
  }

  .site-nav {
    gap: 24px;
  }

  .site-nav > a:not(.button),
  .site-nav__dropdown > summary {
    font-size: 15px;
    font-weight: 600;
  }

  .site-nav > .button {
    font-size: 15px;
    margin-left: 4px;
    min-height: 50px;
    width: 180px;
  }
}

@media (min-width: 75rem) and (max-width: 89.9375rem) {
  .site-header__inner {
    gap: 20px;
    max-width: none;
    min-height: 72px;
    width: calc(100% - 48px);
  }

  .site-nav {
    gap: 16px;
  }

  .site-nav > a:not(.button),
  .site-nav__dropdown > summary {
    font-size: 14px;
    font-weight: 600;
  }

  .site-nav > .button {
    font-size: 14px;
    min-height: 48px;
    width: 160px;
  }
}

@media (min-width: 62rem) and (max-width: 74.9375rem) {
  .site-header__inner {
    gap: 8px;
    max-width: none;
    min-height: 68px;
    width: calc(100% - 32px);
  }

  .site-header .brand-lockup__names {
    display: flex;
  }

  .site-header .brand-lockup {
    gap: 8px;
  }

  .site-header .brand-lockup__mark {
    width: 5rem !important;
  }

  .site-header .brand-lockup__cn {
    font-size: 1rem;
  }

  .site-header .brand-lockup__en {
    font-size: 0.75rem;
    letter-spacing: 0.075em;
    margin-top: 0.25rem;
  }

  .site-nav {
    gap: 5px;
  }

  .site-nav > a:not(.button),
  .site-nav__dropdown > summary {
    font-size: 13px;
    font-weight: 600;
  }

  .site-nav > .button {
    font-size: 13px;
    margin-left: 3px;
    min-height: 46px;
    padding-inline: 10px;
    width: 140px;
  }
}

.breadcrumb-wrap {
  border-bottom: var(--rule-thin) solid var(--color-rule-2);
}

.breadcrumb {
  overflow-x: auto;
  padding-block: var(--space-sm);
  scrollbar-width: thin;
}

.breadcrumb ol {
  align-items: center;
  display: flex;
  gap: var(--space-xs);
  list-style: none;
  margin: 0;
  padding: 0;
  width: max-content;
}

.breadcrumb li {
  color: var(--color-muted);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  white-space: nowrap;
}

.breadcrumb li + li::before {
  content: "/";
  margin-inline-end: var(--space-xs);
}

.breadcrumb a {
  color: var(--color-ink-2);
}

.section {
  padding-block: clamp(5rem, 10vw, 10rem);
}

.section--intro {
  padding-block: clamp(var(--space-xl), 6vw, var(--space-3xl));
}

.section--muted {
  background: var(--color-paper-2);
}

.section--dark {
  background: var(--color-ink);
  color: var(--color-paper);
}

.section--dark h2,
.section--dark h3,
.section--dark a {
  color: var(--color-paper);
}

.split-intro,
.split-feature,
.two-column-content,
.contact-grid {
  align-items: start;
  display: grid;
  gap: clamp(var(--space-xl), 7vw, var(--space-4xl));
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
}

.split-intro > h2 {
  font-size: var(--text-2xl);
}

.three-column {
  display: grid;
  gap: var(--space-xl);
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.site-footer {
  background: var(--color-accent);
  color: var(--color-paper);
  padding-block-start: var(--space-2xl);
}

.site-footer .wordmark,
.site-footer a {
  color: var(--color-paper);
}

.site-footer__grid {
  display: grid;
  gap: var(--space-xl);
  grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr) minmax(0, 1fr);
  padding-block-end: var(--space-2xl);
}

.site-footer__grid nav {
  display: grid;
  gap: var(--space-xs);
}

.site-footer__grid nav a,
.site-footer__grid > div:last-child > a {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  text-decoration: none;
  white-space: nowrap;
}

.site-footer__base {
  border-top: var(--rule-thin) solid var(--color-ink-2);
  display: flex;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  gap: var(--space-md);
  justify-content: space-between;
  padding-block: var(--space-md);
}

.back-to-top {
  background: var(--color-accent);
  border: 0;
  bottom: var(--space-md);
  color: var(--color-accent-ink);
  height: 3rem;
  opacity: 0;
  pointer-events: none;
  position: fixed;
  right: var(--space-md);
  transform: translateY(1rem);
  transition:
    transform var(--dur-base) var(--ease-out),
    opacity var(--dur-short) var(--ease-out);
  width: 3rem;
  z-index: 30;
}

.back-to-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

@media (max-width: 61.9375rem) {
  .site-header__inner {
    justify-content: space-between;
    max-width: var(--container);
    min-height: 4.75rem;
    padding-inline: clamp(var(--space-sm), 4vw, var(--space-xl));
  }

  .nav-toggle {
    display: block;
  }

  .site-nav {
    align-items: stretch;
    background: var(--color-paper);
    border-bottom: var(--rule-thin) solid var(--color-ink);
    color: var(--color-ink);
    display: flex;
    flex-direction: column;
    inset: 4.75rem 0 auto;
    max-height: calc(100svh - 4.75rem);
    opacity: 0;
    overflow-y: auto;
    padding: var(--space-lg);
    pointer-events: none;
    position: fixed;
    transform: translateY(-1rem);
    transition:
      transform var(--dur-base) var(--ease-out),
      opacity var(--dur-short) var(--ease-out);
  }

  .site-nav.is-open {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
  }

  .site-nav > a:not(.button) {
    border-bottom: var(--rule-thin) solid var(--color-rule);
    color: var(--color-ink);
    font-size: var(--text-base);
    padding-block: var(--space-sm);
  }

  .site-nav__dropdown {
    border-bottom: var(--rule-thin) solid var(--color-rule);
  }

  .site-nav__dropdown > summary {
    font-size: var(--text-base);
    justify-content: space-between;
    padding-block: var(--space-sm);
    width: 100%;
  }

  .site-nav__menu,
  .site-nav__dropdown--edge .site-nav__menu {
    border: 0;
    box-shadow: none;
    left: auto;
    min-width: 0;
    max-width: none;
    padding: 0 0 var(--space-sm) var(--space-sm);
    position: static;
    right: auto;
    width: 100%;
  }

  .site-nav__menu a {
    font-size: var(--text-sm);
    white-space: normal;
  }

  .nav-toggle[aria-expanded="true"] > span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .nav-toggle[aria-expanded="true"] > span:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle[aria-expanded="true"] > span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-header,
  .site-nav > a:not(.button),
  .site-nav__dropdown > summary,
  .site-nav__menu a {
    transition-duration: 1ms;
  }
}

@media (max-width: 61.9375rem) {
  .section {
    padding-block: 5rem;
  }
}

@media (max-width: 48rem) {
  .section {
    padding-block: 3.75rem;
  }
  .split-intro,
  .split-feature,
  .two-column-content,
  .contact-grid,
  .three-column,
  .site-footer__grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .site-footer__base {
    align-items: flex-start;
    flex-direction: column;
  }
}