:root,
[data-theme='light'] {
  --font-display: 'Cabinet Grotesk', 'Arial Narrow', sans-serif;
  --font-body: 'Satoshi', Arial, sans-serif;
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.35vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.75vw, 1.5rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.25vw, 2.25rem);
  --text-2xl: clamp(2rem, 1.2rem + 2.5vw, 3.5rem);
  --text-hero: clamp(3rem, 1rem + 7vw, 7.5rem);
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;
  --color-bg: #f1f1ec;
  --color-surface: #fafaf6;
  --color-surface-2: #e6e7e1;
  --color-text: #151917;
  --color-text-muted: #626965;
  --color-text-faint: #959c97;
  --color-text-inverse: #f7f7f2;
  --color-dark: #111513;
  --color-dark-2: #1c211e;
  --color-accent: #d45d2c;
  --color-accent-hover: #b7481d;
  --color-line: rgb(21 25 23 / 14%);
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --transition: 180ms cubic-bezier(0.16, 1, 0.3, 1);
  --content-wide: 90rem;
}

[data-theme='dark'] {
  --color-bg: #101311;
  --color-surface: #171b18;
  --color-surface-2: #202521;
  --color-text: #e6e8e4;
  --color-text-muted: #a1a8a3;
  --color-text-faint: #727973;
  --color-text-inverse: #111513;
  --color-dark: #080a09;
  --color-dark-2: #121613;
  --color-accent: #ef7642;
  --color-accent-hover: #ff8c59;
  --color-line: rgb(230 232 228 / 14%);
}

html[lang='zh'] {
  --font-display: 'Noto Sans SC', 'Cabinet Grotesk', sans-serif;
  --font-body: 'Noto Sans SC', 'Satoshi', sans-serif;
}

.skip-link {
  position: fixed;
  top: var(--space-3);
  left: var(--space-3);
  z-index: 100;
  padding: var(--space-3) var(--space-4);
  color: var(--color-text-inverse);
  background: var(--color-accent);
  transform: translateY(-150%);
}

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

.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 50;
  height: 5rem;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding-inline: clamp(var(--space-4), 4vw, var(--space-16));
  color: #fff;
  border-bottom: 1px solid rgb(255 255 255 / 18%);
  transition:
    background var(--transition),
    color var(--transition),
    transform 300ms cubic-bezier(0.16, 1, 0.3, 1);
}

.site-header.scrolled {
  color: var(--color-text);
  background: color-mix(in srgb, var(--color-bg) 92%, transparent);
  border-bottom-color: var(--color-line);
  backdrop-filter: blur(16px);
}

.brand {
  width: max-content;
  display: inline-flex;
  gap: var(--space-3);
  align-items: center;
  font-size: var(--text-sm);
  font-weight: 700;
  letter-spacing: 0.16em;
}

.brand-mark {
  width: 2rem;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linejoin: round;
}

.desktop-nav {
  display: flex;
  gap: var(--space-8);
  align-items: center;
  font-size: var(--text-xs);
  font-weight: 600;
}

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

.header-actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-3);
  align-items: center;
}

.language-switcher {
  display: flex;
  align-items: center;
  border: 1px solid currentColor;
}

.lang-button {
  min-width: 2.75rem;
  min-height: 2.75rem;
  padding-inline: var(--space-2);
  font-size: var(--text-xs);
  opacity: 0.55;
}

.lang-button.active {
  color: var(--color-text-inverse);
  background: var(--color-accent);
  opacity: 1;
}

.icon-button,
.menu-button {
  width: 2.75rem;
  height: 2.75rem;
  display: grid;
  place-items: center;
  border: 1px solid currentColor;
}

.icon-button svg {
  width: 1.15rem;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
}

.theme-sun {
  display: none;
}

[data-theme='dark'] .theme-moon {
  display: none;
}

[data-theme='dark'] .theme-sun {
  display: block;
}

.header-cta {
  min-height: 2.75rem;
  display: inline-flex;
  align-items: center;
  padding-inline: var(--space-5);
  color: #fff;
  background: var(--color-accent);
  font-size: var(--text-xs);
  font-weight: 700;
}

.header-cta:hover,
.submit-button:hover,
.primary-button:hover {
  background: var(--color-accent-hover);
}

.menu-button,
.mobile-nav {
  display: none;
}

.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  overflow: hidden;
  color: #fff;
  background: var(--color-dark);
}

.hero-image,
.hero-shade,
.hero-grid {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero-image {
  object-fit: cover;
  object-position: 60% center;
}

.hero-shade {
  background:
    linear-gradient(90deg, rgb(6 10 8 / 82%) 0%, rgb(6 10 8 / 44%) 55%, rgb(6 10 8 / 14%) 100%),
    linear-gradient(0deg, rgb(6 10 8 / 65%) 0%, transparent 55%);
}

[data-theme='dark'] .hero-shade {
  background:
    linear-gradient(90deg, rgb(4 7 6 / 93%) 0%, rgb(4 7 6 / 68%) 55%, rgb(4 7 6 / 40%) 100%),
    linear-gradient(0deg, rgb(4 7 6 / 82%) 0%, transparent 62%);
}

[data-theme='dark'] .hero-image {
  filter: brightness(0.78) saturate(0.88);
}

.hero-grid {
  background-image:
    linear-gradient(rgb(255 255 255 / 9%) 1px, transparent 1px),
    linear-gradient(90deg, rgb(255 255 255 / 9%) 1px, transparent 1px);
  background-size: 25% 100%, 25% 100%;
  mask-image: linear-gradient(90deg, #000, transparent 72%);
}

.hero-content {
  position: relative;
  z-index: 2;
  width: min(100%, var(--content-wide));
  margin: auto;
  padding: 10rem clamp(var(--space-4), 5vw, var(--space-20)) var(--space-20);
}

.eyebrow {
  margin-bottom: var(--space-6);
  color: var(--color-accent);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.16em;
}

.eyebrow.light {
  color: #f38a5d;
}

.hero h1 {
  max-width: 10ch;
  font-family: var(--font-display);
  font-size: var(--text-hero);
  font-weight: 500;
  letter-spacing: -0.045em;
}

.hero-bottom {
  display: grid;
  grid-template-columns: minmax(18rem, 34rem) auto;
  gap: var(--space-8);
  align-items: end;
  margin-top: var(--space-10);
}

.hero-bottom p {
  color: rgb(255 255 255 / 78%);
  font-size: var(--text-lg);
}

.primary-button,
.submit-button {
  min-height: 3.5rem;
  display: inline-flex;
  justify-content: space-between;
  gap: var(--space-8);
  align-items: center;
  padding: var(--space-4) var(--space-5);
  color: #fff;
  background: var(--color-accent);
  font-size: var(--text-sm);
  font-weight: 700;
}

.primary-button {
  justify-self: start;
}

.primary-button svg,
.submit-button svg,
.solution-row svg {
  width: 1.25rem;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
}

.hero-index {
  position: absolute;
  right: clamp(var(--space-4), 4vw, var(--space-16));
  bottom: var(--space-8);
  z-index: 2;
  display: flex;
  gap: var(--space-4);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
}

.hero-index span:first-child {
  color: var(--color-accent);
}

.section {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding: clamp(var(--space-20), 9vw, var(--space-32))
    clamp(var(--space-4), 5vw, var(--space-20));
}

.section-number {
  color: var(--color-text-faint);
  font-size: var(--text-xs);
  letter-spacing: 0.12em;
}

.intro {
  display: grid;
  grid-template-columns: 0.5fr 1.5fr 1fr;
  gap: clamp(var(--space-8), 5vw, var(--space-20));
}

.intro h2,
.section-heading h2,
.integration h2,
.principles h2,
.contact h2,
.applications h2 {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 500;
  letter-spacing: -0.03em;
}

.lead {
  margin-top: var(--space-8);
  color: var(--color-text-muted);
}

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

.scope-item {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: var(--space-3);
  padding-block: var(--space-5);
  border-bottom: 1px solid var(--color-line);
}

.scope-item > span {
  color: var(--color-accent);
  font-size: var(--text-xs);
}

.scope-item strong {
  font-size: var(--text-sm);
}

.scope-item p {
  grid-column: 2;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.dark-section {
  max-width: none;
  color: #eff1ed;
  background: var(--color-dark);
}

.dark-section > * {
  max-width: var(--content-wide);
  margin-inline: auto;
}

.section-heading {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: var(--space-16);
  align-items: end;
  margin-bottom: var(--space-16);
}

.section-heading > p {
  color: #a8b0ab;
}

.solution-layout {
  display: grid;
  grid-template-columns: 1.45fr 1fr;
  min-height: 42rem;
}

.solution-feature {
  position: relative;
  min-height: 38rem;
  overflow: hidden;
}

.solution-feature img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.solution-overlay {
  position: absolute;
  inset: auto 0 0;
  padding: var(--space-8);
  background: linear-gradient(transparent, rgb(6 8 7 / 90%));
}

.solution-overlay span,
.solution-code {
  color: #f38a5d;
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.12em;
}

.solution-overlay h3 {
  margin-block: var(--space-3);
  font-size: var(--text-xl);
}

.solution-overlay p {
  color: #bdc4bf;
}

.solution-stack {
  display: grid;
  grid-template-rows: repeat(3, 1fr);
  background: var(--color-dark-2);
}

.solution-row {
  display: grid;
  grid-template-columns: 4rem 1fr 1.5rem;
  gap: var(--space-6);
  align-items: center;
  padding: var(--space-8);
  border-bottom: 1px solid rgb(255 255 255 / 12%);
}

.solution-row h3 {
  margin-bottom: var(--space-3);
  font-size: var(--text-lg);
}

.solution-row p {
  color: #9fa6a1;
  font-size: var(--text-sm);
}

.integration {
  display: grid;
  grid-template-columns: 0.5fr 2.5fr;
  gap: var(--space-8);
}

.integration-title {
  max-width: 54rem;
}

.process {
  grid-column: 2;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin-top: var(--space-20);
}

.process-step {
  padding-right: var(--space-8);
}

.step-top {
  position: relative;
  display: flex;
  align-items: center;
  color: var(--color-text-faint);
  font-size: var(--text-xs);
}

.step-top::after {
  content: '';
  flex: 1;
  height: 1px;
  margin-left: var(--space-3);
  background: var(--color-line);
}

.step-dot {
  position: absolute;
  right: 0;
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background: var(--color-accent);
}

.process-step h3 {
  margin-block: var(--space-8) var(--space-3);
  font-size: var(--text-lg);
}

.process-step p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.applications {
  position: relative;
  min-height: 48rem;
  display: flex;
  align-items: end;
  overflow: hidden;
  color: #fff;
}

.applications > img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.applications::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, rgb(8 11 9 / 88%), rgb(8 11 9 / 15%));
}

.applications-panel {
  position: relative;
  z-index: 2;
  width: min(50rem, 100%);
  margin: 0 0 clamp(var(--space-8), 6vw, var(--space-20))
    clamp(var(--space-4), 5vw, var(--space-20));
  padding: clamp(var(--space-6), 4vw, var(--space-12));
  background: rgb(17 21 19 / 88%);
  backdrop-filter: blur(12px);
}

.application-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 var(--space-8);
  margin-top: var(--space-10);
}

.application-list span {
  padding-block: var(--space-4);
  color: #c5cbc7;
  border-top: 1px solid rgb(255 255 255 / 16%);
  font-size: var(--text-sm);
}

.principles {
  display: grid;
  grid-template-columns: 0.5fr 2.5fr;
  gap: var(--space-8);
}

.principles-intro {
  max-width: 48rem;
}

.principle-grid {
  grid-column: 2;
  display: grid;
  grid-template-columns: 1fr 1.5fr 1fr;
  margin-top: var(--space-16);
  border-block: 1px solid var(--color-line);
}

.principle-grid article {
  min-height: 22rem;
  padding: var(--space-8);
  border-right: 1px solid var(--color-line);
}

.principle-grid article:last-child {
  border: 0;
}

.principle-symbol {
  color: var(--color-accent);
  font-family: var(--font-display);
  font-size: var(--text-2xl);
}

.principle-grid h3 {
  margin-block: var(--space-20) var(--space-4);
  font-size: var(--text-lg);
}

.principle-grid p {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.contact {
  max-width: none;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(var(--space-12), 8vw, var(--space-32));
  color: #f1f3ef;
  background: var(--color-dark);
}

.contact > * {
  width: 100%;
  max-width: 38rem;
}

.contact-copy {
  justify-self: end;
}

.contact-copy p:not(.eyebrow) {
  margin-block: var(--space-8);
  color: #aeb5b0;
}

.contact-copy > a {
  color: #f38a5d;
  border-bottom: 1px solid currentColor;
}

.project-form {
  display: grid;
  gap: var(--space-5);
}

.project-form label {
  display: grid;
  gap: var(--space-2);
  color: #b6bdb8;
  font-size: var(--text-xs);
}

.project-form input,
.project-form select,
.project-form textarea {
  width: 100%;
  padding: var(--space-3) 0;
  color: #fff;
  background: transparent;
  border: 0;
  border-bottom: 1px solid rgb(255 255 255 / 30%);
  border-radius: 0;
}

.project-form option {
  color: #111;
}

.project-form textarea {
  resize: vertical;
}

.form-note {
  color: #7f8882;
  font-size: var(--text-xs);
}

footer {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: var(--space-8);
  align-items: center;
  padding: var(--space-8) clamp(var(--space-4), 5vw, var(--space-20));
  color: var(--color-text-muted);
  background: var(--color-bg);
  font-size: var(--text-xs);
}

footer p:last-child {
  justify-self: end;
}

.footer-brand {
  color: var(--color-text);
}

@media (max-width: 70rem) {
  .desktop-nav,
  .header-cta {
    display: none;
  }

  .site-header {
    grid-template-columns: 1fr auto;
  }

  .menu-button {
    display: grid;
    align-content: center;
    gap: 0.35rem;
  }

  .menu-button span {
    width: 1.2rem;
    height: 1px;
    background: currentColor;
  }

  .mobile-nav {
    position: fixed;
    inset: 5rem 0 auto;
    z-index: 45;
    display: grid;
    padding: var(--space-6);
    color: var(--color-text);
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-line);
    transform: translateY(-140%);
    transition: transform 300ms cubic-bezier(0.16, 1, 0.3, 1);
  }

  .mobile-nav.open {
    transform: translateY(0);
  }

  .mobile-nav a {
    min-height: 3.5rem;
    display: flex;
    align-items: center;
    border-bottom: 1px solid var(--color-line);
  }

  .intro {
    grid-template-columns: 0.35fr 1.65fr;
  }

  .scope-list {
    grid-column: 2;
  }

  .solution-layout {
    grid-template-columns: 1.2fr 1fr;
  }
}

@media (max-width: 48rem) {
  .site-header {
    height: 4.5rem;
    padding-inline: var(--space-4);
  }

  .brand {
    letter-spacing: 0.1em;
  }

  .brand-mark {
    width: 1.75rem;
  }

  .language-switcher {
    border: 0;
  }

  .lang-button {
    min-width: 2.5rem;
    min-height: 2.75rem;
  }

  .lang-button:not(.active) {
    display: none;
  }

  .icon-button {
    display: none;
  }

  .mobile-nav {
    inset-block-start: 4.5rem;
  }

  .hero-content {
    padding: 8rem var(--space-4) var(--space-20);
  }

  .hero h1 {
    max-width: 8ch;
  }

  .hero-bottom {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }

  .hero-bottom p {
    font-size: var(--text-base);
  }

  .hero-index {
    display: none;
  }

  .section {
    padding: var(--space-20) var(--space-4);
  }

  .intro,
  .integration,
  .principles,
  .contact {
    grid-template-columns: 1fr;
  }

  .intro-copy,
  .scope-list,
  .process,
  .principles-intro,
  .principle-grid {
    grid-column: 1;
  }

  .section-heading {
    grid-template-columns: 1fr;
    gap: var(--space-6);
    margin-bottom: var(--space-10);
  }

  .solution-layout {
    grid-template-columns: 1fr;
  }

  .solution-feature {
    min-height: 30rem;
  }

  .solution-row {
    grid-template-columns: 3.5rem 1fr 1.25rem;
    padding: var(--space-6) var(--space-4);
  }

  .process {
    grid-template-columns: 1fr;
    gap: var(--space-10);
    margin-top: var(--space-12);
  }

  .process-step {
    padding-right: 0;
  }

  .applications {
    min-height: 44rem;
  }

  .applications-panel {
    margin: var(--space-4);
  }

  .application-list {
    grid-template-columns: 1fr;
  }

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

  .principle-grid article {
    min-height: auto;
    padding: var(--space-8) 0;
    border-right: 0;
    border-bottom: 1px solid var(--color-line);
  }

  .principle-grid h3 {
    margin-top: var(--space-8);
  }

  .contact-copy {
    justify-self: start;
  }

  footer {
    grid-template-columns: 1fr;
  }

  footer p:last-child {
    justify-self: start;
  }
}