/* ===============================================================
   gsc-rail.ai  —  AIO Division  —  Sibling-Brand v4
   Matches gsc-em.com design language: dark base, baby blue +
   signal green accents, Arial/Calibri/Consolas typography stack.
=============================================================== */

:root {
  /* Color tokens — locked v4 palette */
  --bg:        #000000;
  --bg-soft:   #0A0A0A;
  --bg-card:   #111111;
  --bg-hover:  #161616;
  --border:    #1F1F1F;
  --border-2:  #2A2A2A;
  --text:      #F5F5F5;
  --text-2:    #D4D4D8;
  --text-dim:  #A1A1AA;
  --text-mute: #71717A;
  --baby:      #60A5FA;
  --baby-dark: #3B82F6;
  --green:     #22C55E;
  --green-dim: #166534;
  --amber:     #F59E0B;
  --rose:      #F472B6;
  --purple:    #C084FC;

  /* Typography stack — same as gsc-em.com v4 */
  --f-head: "Arial", "Helvetica Neue", Helvetica, sans-serif;
  --f-body: "Calibri", "Segoe UI", system-ui, sans-serif;
  --f-mono: "Consolas", "Courier New", monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--f-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: var(--baby); text-decoration: none; transition: color 0.15s ease; }
a:hover { color: var(--green); }

code {
  font-family: var(--f-mono);
  font-size: 0.92em;
  background: var(--bg-card);
  padding: 2px 6px;
  border-radius: 3px;
  border: 1px solid var(--border);
  color: var(--text);
}

strong { color: var(--text); font-weight: 600; }

.accent-green { color: var(--green); }
.accent-baby  { color: var(--baby); }

/* ===============================================================
   TOP NAV
=============================================================== */
.topnav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(0, 0, 0, 0.9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 14px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand {
  font-family: var(--f-head);
  display: inline-flex;
  align-items: baseline;
  gap: 10px;
  color: var(--text);
}
.brand-mark {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--text);
}
.brand-divider { color: var(--text-mute); font-size: 14px; }
.brand-sub {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--text-dim);
  font-weight: 600;
}
.brand:hover .brand-sub { color: var(--green); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.8px;
}
.nav-links a {
  color: var(--text-dim);
  text-transform: uppercase;
  padding: 4px 0;
  border-bottom: 1px solid transparent;
}
.nav-links a:hover {
  color: var(--text);
  border-bottom-color: var(--baby);
}
.nav-cta {
  color: var(--green) !important;
  border: 1px solid var(--green-dim);
  padding: 6px 14px !important;
  border-radius: 2px;
}
.nav-cta:hover {
  background: var(--green-dim);
  color: var(--text) !important;
  border-color: var(--green);
}

/* ===============================================================
   HERO
=============================================================== */
.hero {
  padding: 96px 32px 72px;
  border-bottom: 1px solid var(--border);
  background:
    radial-gradient(ellipse at top right, rgba(34, 197, 94, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at bottom left, rgba(96, 165, 250, 0.08) 0%, transparent 50%),
    var(--bg);
}
.hero-inner { max-width: 1100px; margin: 0 auto; }

.hero-eyebrow {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 2px;
  color: var(--green);
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 32px;
  font-weight: 600;
}
.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 12px var(--green);
  animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.hero-h1 {
  font-family: var(--f-head);
  font-size: clamp(40px, 6vw, 68px);
  line-height: 1.05;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 32px;
  letter-spacing: -1px;
}

.hero-p {
  font-size: 18px;
  line-height: 1.6;
  color: var(--text-2);
  max-width: 880px;
  margin-bottom: 56px;
}

.hero-stat-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 16px;
}
.hero-stat {
  border-left: 2px solid var(--border-2);
  padding-left: 20px;
}
.hero-stat-num {
  font-family: var(--f-head);
  font-size: 36px;
  font-weight: 700;
  color: var(--green);
  letter-spacing: -0.5px;
  line-height: 1.1;
  margin-bottom: 6px;
}
.hero-stat-label {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 1.5px;
  color: var(--text-mute);
  font-weight: 600;
}

/* ===============================================================
   AGENTIC SURFACE STRIP
=============================================================== */
.agentic-surface {
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
  padding: 32px;
}
.surface-inner { max-width: 1280px; margin: 0 auto; }
.surface-eyebrow {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 2px;
  color: var(--baby);
  margin-bottom: 16px;
  font-weight: 600;
}
.surface-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px 32px;
  font-size: 13px;
  color: var(--text-dim);
  font-family: var(--f-body);
  line-height: 1.5;
}
.surface-cell strong { color: var(--text); }

/* ===============================================================
   SECTIONS — base
=============================================================== */
.section {
  padding: 96px 32px;
  border-bottom: 1px solid var(--border);
}
.section-dark { background: var(--bg-soft); }

.sec-inner { max-width: 1100px; margin: 0 auto; }

.sec-eyebrow {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 2px;
  color: var(--baby);
  font-weight: 600;
  margin-bottom: 24px;
}

.sec-h2 {
  font-family: var(--f-head);
  font-size: clamp(30px, 4.5vw, 48px);
  line-height: 1.1;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 24px;
  letter-spacing: -0.5px;
  max-width: 900px;
}

.sec-lead {
  font-size: 17px;
  line-height: 1.65;
  color: var(--text-2);
  max-width: 880px;
  margin-bottom: 56px;
}

.sec-closer {
  margin-top: 48px;
  font-size: 16px;
  color: var(--text-dim);
  font-style: italic;
  text-align: center;
}

/* ===============================================================
   §01  WHAT CHANGED  —  Banner cards
=============================================================== */
.banners-eyebrow {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--text-mute);
  margin-bottom: 24px;
  font-weight: 600;
}
.banners-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}
.banner-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 24px;
  transition: border-color 0.2s ease, background 0.2s ease;
}
.banner-card:hover { border-color: var(--baby-dark); background: var(--bg-hover); }
.banner-name {
  font-family: var(--f-head);
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 4px;
}
.banner-region {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 1.5px;
  color: var(--baby);
  font-weight: 600;
  margin-bottom: 16px;
}
.banner-stack {
  font-size: 14px;
  color: var(--text-2);
  margin-bottom: 8px;
}
.banner-note {
  font-size: 12px;
  color: var(--text-mute);
  font-style: italic;
  line-height: 1.5;
}

/* ===============================================================
   §02  WHO WE ARE  —  Pillar cards
=============================================================== */
.pillar-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}
.pillar-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 32px 28px;
  transition: border-color 0.2s ease;
}
.pillar-card:hover { border-color: var(--green-dim); }
.pillar-num {
  font-family: var(--f-head);
  font-size: 32px;
  font-weight: 700;
  color: var(--baby);
  margin-bottom: 12px;
  letter-spacing: -0.5px;
}
.pillar-title {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 2px;
  color: var(--green);
  font-weight: 600;
  margin-bottom: 12px;
}
.pillar-h3 {
  font-family: var(--f-head);
  font-size: 22px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 16px;
  line-height: 1.2;
}
.pillar-body {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-2);
  margin-bottom: 20px;
}
.pillar-mark {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.5px;
  color: var(--text-mute);
  border-top: 1px solid var(--border);
  padding-top: 14px;
  font-style: italic;
}

/* ===============================================================
   §03  RAILS  —  three-card grid with per-rail color stripe
=============================================================== */
.rail-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}
.rail-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  position: relative;
  overflow: hidden;
  transition: border-color 0.2s ease;
  display: flex;
  flex-direction: column;
}
.rail-card:hover { border-color: var(--text-mute); }
.rail-stripe {
  height: 4px;
  background: var(--baby);
}
.rail-hpl .rail-stripe { background: var(--baby); }
.rail-bpl .rail-stripe { background: var(--purple); }
.rail-bpc .rail-stripe { background: var(--rose); }

.rail-code {
  font-family: var(--f-mono);
  font-size: 22px;
  font-weight: 700;
  color: var(--text);
  padding: 24px 28px 8px;
  letter-spacing: 0.5px;
}
.rail-cat {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 1.5px;
  font-weight: 600;
  padding: 0 28px 16px;
}
.rail-hpl .rail-cat { color: var(--baby); }
.rail-bpl .rail-cat { color: var(--purple); }
.rail-bpc .rail-cat { color: var(--rose); }

.rail-h3 {
  font-family: var(--f-head);
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  padding: 0 28px 16px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 16px;
}

.rail-section-label {
  font-family: var(--f-mono);
  font-size: 9px;
  letter-spacing: 1.5px;
  color: var(--text-mute);
  font-weight: 600;
  padding: 0 28px;
  margin-bottom: 6px;
}
.rail-body {
  font-size: 13px;
  line-height: 1.55;
  color: var(--text-2);
  padding: 0 28px 16px;
}

.rail-meta {
  margin-top: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 28px;
  border-top: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.02);
}
.rail-link {
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--baby);
}
.rail-status {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 1.5px;
  color: var(--green);
  background: rgba(34, 197, 94, 0.1);
  border: 1px solid var(--green-dim);
  padding: 4px 10px;
  border-radius: 2px;
  font-weight: 600;
}

/* ===============================================================
   §04  PROOF  —  4-card grid + reach block
=============================================================== */
.proof-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-bottom: 48px;
}
.proof-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 32px 24px;
  text-align: left;
}
.proof-num {
  font-family: var(--f-head);
  font-size: 40px;
  font-weight: 700;
  color: var(--green);
  letter-spacing: -1px;
  line-height: 1.05;
  margin-bottom: 8px;
}
.proof-label {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 1.8px;
  color: var(--baby);
  font-weight: 600;
  margin-bottom: 12px;
}
.proof-note {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
}

.reach-block {
  border: 1px solid var(--border);
  background: var(--bg-card);
  padding: 24px 28px;
}
.reach-eyebrow {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 2px;
  color: var(--baby);
  font-weight: 600;
  margin-bottom: 10px;
}
.reach-body {
  font-size: 15px;
  color: var(--text-2);
  line-height: 1.6;
}

/* ===============================================================
   §05  HOW IT WORKS  &  §06  ONBOARDING  —  flow steps
=============================================================== */
.flow-list {
  list-style: none;
  display: grid;
  gap: 16px;
}
.flow-step {
  display: grid;
  grid-template-columns: 96px 1fr;
  gap: 24px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 24px 28px;
  align-items: start;
  transition: border-color 0.2s ease;
}
.flow-step:hover { border-color: var(--baby-dark); }
.flow-num {
  font-family: var(--f-head);
  font-size: 36px;
  font-weight: 700;
  color: var(--baby);
  letter-spacing: -0.5px;
  line-height: 1;
}
.flow-title {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 2px;
  color: var(--green);
  font-weight: 600;
  margin-bottom: 10px;
}
.flow-body p {
  font-size: 15px;
  color: var(--text-2);
  line-height: 1.6;
}

/* ===============================================================
   §07  SECURITY  —  9-control grid
=============================================================== */
.sec-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}
.sec-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 24px;
  display: grid;
  grid-template-columns: 24px 1fr;
  gap: 14px;
  align-items: start;
}
.sec-card-mark {
  color: var(--baby);
  font-size: 14px;
  line-height: 1.4;
}
.sec-card-title {
  font-family: var(--f-head);
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}
.sec-card-body {
  font-size: 13px;
  line-height: 1.5;
  color: var(--text-dim);
}

/* ===============================================================
   §08  CONTACT  —  form, team cards, offices
=============================================================== */
.contact-form {
  display: grid;
  gap: 20px;
  max-width: 720px;
  margin-bottom: 24px;
}
.form-row { display: grid; gap: 8px; }
.form-row label {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--text-dim);
  font-weight: 600;
}
.form-row input,
.form-row select,
.form-row textarea {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 12px 14px;
  font-family: var(--f-body);
  font-size: 15px;
  border-radius: 2px;
  transition: border-color 0.15s ease;
}
.form-row input:focus,
.form-row select:focus,
.form-row textarea:focus {
  outline: none;
  border-color: var(--baby);
}
.form-row textarea { resize: vertical; min-height: 120px; }

.form-submit {
  background: var(--green-dim);
  color: var(--text);
  border: 1px solid var(--green);
  padding: 14px 28px;
  font-family: var(--f-mono);
  font-size: 12px;
  letter-spacing: 1.8px;
  font-weight: 600;
  cursor: pointer;
  border-radius: 2px;
  transition: background 0.15s ease, transform 0.1s ease;
  justify-self: start;
}
.form-submit:hover { background: var(--green); }
.form-submit:active { transform: translateY(1px); }

.contact-direct {
  font-size: 14px;
  color: var(--text-dim);
  margin-bottom: 56px;
}

.contact-team {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
  margin-bottom: 48px;
}
.contact-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  padding: 24px;
}
.contact-name {
  font-family: var(--f-head);
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 4px;
}
.contact-title {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--baby);
  font-weight: 600;
  margin-bottom: 16px;
}
.contact-line {
  font-size: 14px;
  color: var(--text-2);
  margin-bottom: 6px;
}
.contact-line a { color: var(--text-2); }
.contact-line a:hover { color: var(--green); }
.contact-channel {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 1px;
  color: var(--text-mute);
  margin-left: 6px;
}

.offices-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}
.office-card {}
.office-country {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 1.5px;
  color: var(--baby);
  font-weight: 600;
  margin-bottom: 6px;
}
.office-city {
  font-family: var(--f-head);
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}
.office-addr {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
}

/* ===============================================================
   FOOTER
=============================================================== */
.footer {
  background: var(--bg);
  border-top: 1px solid var(--border);
  padding: 56px 32px 32px;
}
.footer-inner {
  max-width: 1280px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 32px;
  margin-bottom: 32px;
}
.footer-block {}
.footer-eyebrow {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 2px;
  color: var(--text-mute);
  font-weight: 600;
  margin-bottom: 12px;
}
.footer-divisions a,
.footer-divisions strong {
  font-family: var(--f-mono);
  font-size: 13px;
  color: var(--text-2);
}
.footer-divisions strong { color: var(--green); }
.footer-rails {
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 8px;
  line-height: 1.7;
}
.footer-rails a { color: var(--text-2); }
.footer-rails a:hover { color: var(--green); }
.footer-protocol {
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 6px;
}
.footer-protocol code {
  background: transparent;
  border: none;
  padding: 0;
  color: var(--text-2);
}
.footer-sep { color: var(--text-mute); margin: 0 6px; }

.footer-bottom {
  max-width: 1280px;
  margin: 0 auto;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  font-family: var(--f-mono);
  font-size: 11px;
  color: var(--text-mute);
  letter-spacing: 0.5px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  align-items: center;
}

/* ===============================================================
   RESPONSIVE
=============================================================== */
@media (max-width: 768px) {
  .nav-links a:not(.nav-cta) { display: none; }
  .nav-links { gap: 12px; }
  .hero { padding: 64px 24px 56px; }
  .section { padding: 64px 24px; }
  .agentic-surface { padding: 24px; }
  .hero-stat-row { grid-template-columns: 1fr; gap: 16px; }
  .flow-step { grid-template-columns: 1fr; gap: 12px; }
  .flow-num { font-size: 28px; }
}