/* ============================================================
   NorthGrid — corporate homepage
   Brief: precise, intelligent, professional, premium, mission
   critical, minimalistic, modern, trustworthy, engineered,
   resilient. Never: flashy, gamer, hacker, cyberpunk, military
   propaganda, loud/aggressive, overly futuristic.

   Direction: mostly a cool steel-white surface (not warm cream,
   not near-black-with-neon) with deep graphite ink and one
   restrained, desaturated steel-blue accent used sparingly.
   One dark charcoal band (Approach, Contact) for gravitas and
   contrast — not a sitewide dark/neon "hacker" theme.

   Type: Space Grotesk for display (geometric, technical,
   controlled) · IBM Plex Sans for body/UI · IBM Plex Mono for
   eyebrows, spec codes, and data labels — a quiet nod to
   engineering documentation, used as signal, not decoration.

   Signature element: an abstract circuit/schematic diagram in
   the hero, built from hairline strokes and node points — no
   glow, no gradient, no neon.
   ============================================================ */

:root {
  --bg: #f1f2f4;
  --surface: #ffffff;
  --ink: #12151a;
  --ink-soft: #454b54;
  --muted: #767c86;
  --line: #dadde2;
  --line-strong: #c3c8d0;

  --accent: #33507a;
  --accent-soft: #e7ebf1;
  --accent-line: #c3cede;

  --dark-bg: #12151a;
  --dark-surface: #191d24;
  --dark-ink: #f1f2f4;
  --dark-ink-soft: #b9bec8;
  --dark-line: rgba(255, 255, 255, 0.12);
  --dark-accent: #8ba3c9;

  --radius: 3px;
  --max: 1180px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
  font-family: "Space Grotesk", "IBM Plex Sans", sans-serif;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: inherit;
  margin: 0;
}

p { margin: 0; }

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

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 32px;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--ink);
  color: #fff;
  padding: 10px 16px;
  z-index: 100;
}
.skip-link:focus { left: 12px; top: 12px; }

.eyebrow {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 0 0 14px;
}

.section-dark .eyebrow { color: var(--dark-accent); }

/* ---------- buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 22px;
  border-radius: var(--radius);
  font-size: 0.88rem;
  font-weight: 500;
  border: 1px solid transparent;
  transition: background 120ms ease, border-color 120ms ease, color 120ms ease;
}

.btn-primary {
  background: var(--ink);
  color: #fff;
}
.btn-primary:hover { background: var(--accent); }

.section-dark .btn-primary,
.hero .btn-primary { background: var(--ink); }

.btn-ghost {
  border-color: var(--line-strong);
  color: var(--ink);
}
.btn-ghost:hover { border-color: var(--ink); }

/* ---------- header ---------- */

.site-header {
  position: sticky;
  top: 0;
  background: rgba(241, 242, 244, 0.92);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--line);
  z-index: 50;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.wordmark {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-family: "Space Grotesk", sans-serif;
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.04em;
  color: var(--ink);
}

.mark { width: 22px; height: 22px; color: var(--accent); flex-shrink: 0; }
.site-footer .mark { color: var(--dark-accent); }

.site-nav {
  display: flex;
  gap: 32px;
}

.site-nav a {
  font-size: 0.88rem;
  color: var(--ink-soft);
  padding: 4px 0;
  border-bottom: 1px solid transparent;
}
.site-nav a:hover { color: var(--ink); border-color: var(--line-strong); }

.header-actions { display: flex; align-items: center; gap: 14px; }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: transparent;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  cursor: pointer;
}
.nav-toggle span { display: block; height: 1.5px; background: var(--ink); }

/* ---------- hero ---------- */

.hero { padding: 88px 0 64px; }

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 0.85fr;
  gap: 48px;
  align-items: center;
}

.hero h1 {
  font-size: 3.4rem;
  line-height: 1.08;
  margin-bottom: 22px;
}

.hero-lede {
  color: var(--ink-soft);
  font-size: 1.05rem;
  max-width: 46ch;
  margin-bottom: 30px;
}

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

.hero-diagram { width: 100%; }

.schematic { width: 100%; height: auto; }

.schematic-grid line { stroke: var(--line); stroke-width: 1; }
.schematic-lines path { fill: none; stroke: var(--accent); stroke-width: 1.3; opacity: 0.75; }
.schematic-nodes circle { fill: var(--surface); stroke: var(--ink-soft); stroke-width: 1.3; }
.schematic-node-active { fill: var(--accent); }
.schematic-label {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 10px;
  fill: var(--ink-soft);
  letter-spacing: 0.04em;
}

/* ---------- principles strip ---------- */

.strip {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}

.strip-inner {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
}

.strip-item {
  padding: 26px 0;
  border-left: 1px solid var(--line);
  padding-left: 28px;
}
.strip-item:first-child { border-left: none; padding-left: 0; }

.strip-label {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 8px;
}

.strip-value {
  font-family: "Space Grotesk", sans-serif;
  font-weight: 600;
  font-size: 1.15rem;
}

/* ---------- sections (shared) ---------- */

.section { padding: 96px 0; }

.section-head { max-width: 640px; margin-bottom: 52px; }
.section-head h2 { font-size: 2rem; line-height: 1.18; }

.section-dark {
  background: var(--dark-bg);
  color: var(--dark-ink);
}
.section-dark h2, .section-dark h3 { color: var(--dark-ink); }
.section-dark p { color: var(--dark-ink-soft); }

/* ---------- capabilities grid ---------- */

.cap-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.cap-card {
  padding: 30px 28px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.cap-code {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 0.74rem;
  color: var(--accent);
  letter-spacing: 0.06em;
  margin-bottom: 14px;
}

.cap-card h3 {
  font-size: 1.08rem;
  margin-bottom: 10px;
}

.cap-card p { color: var(--ink-soft); font-size: 0.92rem; }

/* ---------- approach ---------- */

.approach-grid {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: 56px;
}

.approach-lede { font-size: 1rem; max-width: 42ch; }

.approach-list {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.approach-item {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 18px;
  padding-top: 24px;
  border-top: 1px solid var(--dark-line);
}
.approach-item:first-child { padding-top: 0; border-top: none; }

.approach-index {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 0.85rem;
  color: var(--dark-accent);
}

.approach-item h3 { font-size: 1.05rem; margin-bottom: 8px; }
.approach-item p { font-size: 0.92rem; }

/* ---------- sectors ---------- */

.sector-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.sector-card {
  background: var(--surface);
  padding: 32px 28px;
}

.sector-card h3 { font-size: 1.15rem; margin-bottom: 10px; }
.sector-card p { color: var(--ink-soft); font-size: 0.93rem; }

/* ---------- contact ---------- */

.contact-grid {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: 56px;
  align-items: start;
}

.contact-form {
  background: var(--dark-surface);
  border: 1px solid var(--dark-line);
  border-radius: var(--radius);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.contact-form label {
  display: flex;
  flex-direction: column;
  gap: 7px;
  font-size: 0.85rem;
  color: var(--dark-ink-soft);
}

.contact-form input,
.contact-form select,
.contact-form textarea {
  font: inherit;
  background: var(--dark-bg);
  border: 1px solid var(--dark-line);
  border-radius: var(--radius);
  color: var(--dark-ink);
  padding: 10px 12px;
}

.contact-form input:focus-visible,
.contact-form select:focus-visible,
.contact-form textarea:focus-visible {
  outline: none;
  border-color: var(--dark-accent);
}

.contact-form textarea { resize: vertical; min-height: 90px; }

.contact-form .btn-primary { align-self: flex-start; background: var(--dark-accent); color: var(--dark-bg); }
.contact-form .btn-primary:hover { background: #a3b8da; }

.form-note {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 0.72rem;
  color: var(--muted);
}

/* ---------- footer ---------- */

.site-footer {
  background: var(--dark-bg);
  color: var(--dark-ink-soft);
  border-top: 1px solid var(--dark-line);
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 36px 32px;
}

.site-footer .wordmark { color: var(--dark-ink); }

.footer-tagline {
  font-family: "IBM Plex Mono", ui-monospace, monospace;
  font-size: 0.76rem;
  color: var(--muted);
  margin-top: 8px;
}

.footer-nav { display: flex; gap: 24px; }
.footer-nav a { font-size: 0.85rem; }
.footer-nav a:hover { color: var(--dark-ink); }

.footer-legal {
  font-size: 0.78rem;
  color: var(--muted);
  width: 100%;
  border-top: 1px solid var(--dark-line);
  padding-top: 20px;
  margin-top: 4px;
}

/* ---------- responsive ---------- */

@media (max-width: 980px) {
  .hero-inner { grid-template-columns: 1fr; }
  .hero-diagram { order: -1; max-width: 340px; margin: 0 auto; }
  .approach-grid, .contact-grid { grid-template-columns: 1fr; }
  .cap-grid { grid-template-columns: repeat(2, 1fr); }
  .sector-grid { grid-template-columns: 1fr; }
}

@media (max-width: 760px) {
  .site-nav { display: none; }
  .nav-toggle { display: flex; }

  .site-nav.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--line);
    padding: 16px 32px 24px;
    gap: 4px;
  }
  .site-nav.open a { padding: 10px 0; border-bottom: 1px solid var(--line); }

  .hero h1 { font-size: 2.4rem; }
  .strip-inner { grid-template-columns: 1fr; }
  .strip-item { border-left: none; padding-left: 0; border-top: 1px solid var(--line); padding-top: 18px; }
  .strip-item:first-child { border-top: none; padding-top: 0; }
  .cap-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .footer-legal { order: 3; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}