/* ── Header / Nav ─────────────────────────────────────────── */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 50;
  background: rgba(5, 11, 26, 0.65);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: background var(--transition-mid), border-color var(--transition-mid);
}
.site-header.is-scrolled {
  background: rgba(5, 11, 26, 0.94);
  border-bottom-color: var(--color-line);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-height);
  padding-top: var(--space-3);
  padding-bottom: var(--space-3);
  gap: var(--space-6);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-serif);
}
.brand-mark {
  width: 40px; height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 700;
  font-style: italic;
  color: var(--color-bg-deep);
  background: var(--color-accent);
  border-radius: var(--radius-sm);
  box-shadow: 4px 4px 0 0 var(--color-accent-warm);
  flex-shrink: 0;
}
.brand-name {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}
.brand-primary {
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: 0.005em;
  color: var(--color-text-primary);
}
.brand-sub {
  font-family: var(--font-sans);
  font-size: 0.7rem;
  color: var(--color-text-muted);
  letter-spacing: 0.06em;
  margin-top: 2px;
}

.primary-nav ul {
  display: flex;
  gap: var(--space-8);
}
.primary-nav a {
  font-family: var(--font-sans);
  font-size: var(--fs-small);
  letter-spacing: 0.04em;
  color: var(--color-text-secondary);
  position: relative;
  padding: var(--space-2) 0;
}
.primary-nav a::after {
  content: '';
  position: absolute;
  left: 0; bottom: 2px;
  width: 0; height: 1px;
  background: var(--color-accent);
  transition: width var(--transition-mid);
}
.primary-nav a:hover { color: var(--color-text-primary); }
.primary-nav a:hover::after { width: 100%; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}
.nav-toggle span {
  display: block;
  width: 24px; height: 2px;
  background: var(--color-text-primary);
  transition: var(--transition-fast);
}

/* ── Hero ─────────────────────────────────────────────────── */
.hero {
  position: relative;
  padding-top: clamp(140px, 18vh, 200px);
  padding-bottom: var(--section-pad);
  min-height: 100vh;
  display: flex;
  align-items: center;
  background:
    radial-gradient(ellipse at 75% 25%, rgba(94, 234, 212, 0.10), transparent 55%),
    radial-gradient(ellipse at 12% 80%, rgba(74, 158, 255, 0.07), transparent 50%),
    var(--color-bg-deep);
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--color-grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-grid-line) 1px, transparent 1px);
  background-size: 80px 80px;
  -webkit-mask-image: radial-gradient(ellipse at center, black 30%, transparent 75%);
          mask-image: radial-gradient(ellipse at center, black 30%, transparent 75%);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
  position: relative;
  z-index: 2;
}

.hero-copy { max-width: 640px; }
.hero-title {
  font-size: var(--fs-display);
  margin-top: var(--space-6);
  margin-bottom: var(--space-6);
  letter-spacing: -0.02em;
  font-weight: 500;
}
.hero-lede {
  font-size: clamp(1.05rem, 1.5vw, 1.25rem);
  color: var(--color-text-secondary);
  max-width: 56ch;
  margin-bottom: var(--space-12);
  line-height: 1.6;
}
.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  margin-bottom: var(--space-16);
}
.hero-meta {
  display: grid;
  grid-template-columns: repeat(3, auto);
  justify-content: start;
  gap: var(--space-12);
  border-top: 1px solid var(--color-line);
  padding-top: var(--space-6);
  margin: 0;
}
.hero-meta div { margin: 0; }
.hero-meta dt {
  font-size: var(--fs-eyebrow);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
  font-family: var(--font-sans);
}
.hero-meta dd {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 1.125rem;
  color: var(--color-text-primary);
}

.hero-viz {
  position: relative;
  aspect-ratio: 1 / 1;
  max-width: 560px;
  width: 100%;
  margin-left: auto;
  filter: drop-shadow(0 0 60px rgba(94, 234, 212, 0.18));
}
.hero-viz svg { width: 100%; height: 100%; }

.hero-scroll-hint {
  position: absolute;
  bottom: var(--space-8);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-sans);
  font-size: var(--fs-eyebrow);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  z-index: 2;
}
.hero-scroll-line {
  width: 1px; height: 48px;
  background: linear-gradient(to bottom, var(--color-accent), transparent);
}

/* ── Section base ─────────────────────────────────────────── */
.section {
  padding-top: var(--section-pad);
  padding-bottom: var(--section-pad);
  position: relative;
}
.section-about    { background: var(--color-bg-primary); }
.section-services { background: var(--color-bg-deep); }
.section-solutions{ background: var(--color-bg-primary); }
.section-metrics  {
  background: var(--color-bg-deep);
  padding-top: var(--space-20);
  padding-bottom: var(--space-20);
  border-top: 1px solid var(--color-line);
  border-bottom: 1px solid var(--color-line);
}
.section-careers  { background: var(--color-bg-primary); }
.section-contact  { background: var(--color-bg-deep); }

.section-head {
  display: grid;
  grid-template-columns: auto 1fr;
  column-gap: var(--space-8);
  row-gap: var(--space-3);
  align-items: baseline;
  margin-bottom: var(--space-20);
  padding-bottom: var(--space-8);
  border-bottom: 1px solid var(--color-line);
}
.section-num {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 1.25rem;
  color: var(--color-accent-warm);
  letter-spacing: 0.1em;
  align-self: stretch;
  grid-row: span 2;
  border-right: 1px solid var(--color-line);
  padding-right: var(--space-6);
  display: flex;
  align-items: center;
}
.section-title {
  font-size: var(--fs-h2);
  font-weight: 500;
}
.section-sub {
  color: var(--color-text-secondary);
  margin: 0;
  max-width: 60ch;
  grid-column: 2;
  font-size: 1.05rem;
}

/* ── Footer ───────────────────────────────────────────────── */
.site-footer {
  background: var(--color-bg-deep);
  border-top: 1px solid var(--color-line);
  padding-top: var(--space-12);
  padding-bottom: var(--space-12);
}
.footer-grid {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-8);
  flex-wrap: wrap;
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}
.footer-name {
  font-family: var(--font-serif);
  font-size: 1.125rem;
  margin: 0;
  color: var(--color-text-primary);
}
.footer-zh {
  font-family: var(--font-sans);
  font-size: var(--fs-small);
  color: var(--color-text-muted);
  margin: 0;
  letter-spacing: 0.05em;
}
.footer-meta {
  text-align: right;
  color: var(--color-text-secondary);
  font-size: var(--fs-small);
}
.footer-meta p { margin: 0 0 var(--space-2); }
.footer-fineprint { color: var(--color-text-muted); font-size: 0.75rem; }