/* ============================================
   NEXUS SIGNAL — Shared stylesheet
   Institutional intelligence register
   With meaningful motion
   ============================================ */

:root {
  --bg: #0c0f14;
  --bg-elevated: #11151c;
  --surface: #161b23;
  --surface-2: #1a2029;
  --border: #1f2630;
  --border-bright: #2a323e;
  --text: #d8dde3;
  --text-secondary: #a8b0bb;
  --text-muted: #6f7785;
  --text-dim: #4a525e;
  --accent: #7eb3c4;
  --accent-dim: rgba(126, 179, 196, 0.10);
  --accent-line: rgba(126, 179, 196, 0.35);
  --display: 'Source Serif 4', Georgia, serif;
  --body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --mono: 'JetBrains Mono', monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--body);
  font-weight: 400;
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: 'kern' 1, 'liga' 1;
}
a { color: inherit; text-decoration: none; }
.container { max-width: 1180px; margin: 0 auto; padding: 0 32px; }

/* ===== TOP BAR ===== */
.topbar {
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  padding: 10px 0;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}
.topbar-inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}
.topbar-left { display: flex; gap: 32px; }
.topbar-item { display: flex; gap: 8px; align-items: center; }
.topbar-item-label { color: var(--text-dim); }
.topbar-item-value { color: var(--text-secondary); }
.topbar-right { color: var(--text-dim); }
.topbar-dot {
  width: 5px; height: 5px; border-radius: 50%;
  background: var(--accent);
  display: inline-block;
}
@media (max-width: 640px) {
  .topbar-left { gap: 16px; }
  .topbar-right { display: none; }
}

/* ===== NAVIGATION ===== */
nav.primary {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(12, 15, 20, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 18px 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.logo { display: flex; align-items: center; gap: 12px; }
.logo-mark { width: 24px; height: 24px; flex-shrink: 0; }
.logo-text {
  font-family: var(--display);
  font-weight: 500;
  font-size: 19px;
  letter-spacing: -0.01em;
  color: var(--text);
}
.nav-links {
  display: flex;
  gap: 32px;
  font-size: 14px;
  color: var(--text-secondary);
}
.nav-links a { transition: color 0.2s; }
.nav-links a:hover, .nav-links a.current { color: var(--text); }
.nav-cta {
  color: var(--accent);
  font-size: 14px;
  font-weight: 500;
  padding: 8px 0;
  border-bottom: 1px solid var(--accent-line);
  transition: all 0.2s;
}
.nav-cta:hover { border-bottom-color: var(--accent); color: var(--text); }
@media (max-width: 768px) { .nav-links { display: none; } }

/* ===== BUTTONS / LINKS ===== */
.btn-primary {
  background: var(--accent);
  color: var(--bg);
  padding: 14px 26px;
  font-family: var(--body);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: background 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  border: none;
  cursor: pointer;
  border-radius: 2px;
}
.btn-primary:hover { background: #a8c9d6; }
.btn-text {
  color: var(--text-secondary);
  padding: 14px 0;
  font-size: 14px;
  font-weight: 400;
  transition: color 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: transparent;
  border: none;
  cursor: pointer;
  font-family: var(--body);
}
.btn-text:hover { color: var(--text); }
.arrow { display: inline-block; transition: transform 0.2s ease; color: var(--accent); }
.btn-primary .arrow { color: var(--bg); opacity: 0.7; }
.btn-primary:hover .arrow, .btn-text:hover .arrow { transform: translateX(3px); }

/* ===== TYPOGRAPHY HELPERS ===== */
.section-label {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--text-muted);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-bottom: 24px;
}
.section-title {
  font-family: var(--display);
  font-size: clamp(28px, 3.8vw, 44px);
  line-height: 1.2;
  font-weight: 400;
  letter-spacing: -0.015em;
  margin-bottom: 28px;
  max-width: 820px;
  color: var(--text);
}
.section-title em { font-style: italic; color: var(--accent); }
.section-sub {
  font-size: 17px;
  color: var(--text-secondary);
  max-width: 680px;
  margin-bottom: 56px;
  line-height: 1.65;
}

/* ===== MOTION — meaningful, restrained ===== */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.7s cubic-bezier(0.2, 0.6, 0.2, 1),
              transform 0.7s cubic-bezier(0.2, 0.6, 0.2, 1);
}
.reveal.visible { opacity: 1; transform: translateY(0); }
.reveal.delay-1 { transition-delay: 0.08s; }
.reveal.delay-2 { transition-delay: 0.16s; }
.reveal.delay-3 { transition-delay: 0.24s; }
.reveal.delay-4 { transition-delay: 0.32s; }
.reveal.delay-5 { transition-delay: 0.40s; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
.fade-in { animation: fadeIn 0.7s cubic-bezier(0.2, 0.6, 0.2, 1) backwards; }
.fade-in.d1 { animation-delay: 0.05s; }
.fade-in.d2 { animation-delay: 0.15s; }
.fade-in.d3 { animation-delay: 0.28s; }
.fade-in.d4 { animation-delay: 0.40s; }

.flow-line {
  stroke-dasharray: 3 7;
  animation: flow 3s linear infinite;
}
@keyframes flow {
  from { stroke-dashoffset: 60; }
  to { stroke-dashoffset: 0; }
}

.node-pulse { animation: nodePulse 4s ease-in-out infinite; }
@keyframes nodePulse {
  0%, 100% { opacity: 0.45; }
  50% { opacity: 1; }
}

/* ===== DIAGRAM FRAME ===== */
.diagram-frame {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 48px;
  margin-top: 16px;
  position: relative;
  overflow: hidden;
}
.diagram-frame::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent-line), transparent);
}
@media (max-width: 640px) { .diagram-frame { padding: 24px; } }

/* ===== FOOTER ===== */
footer {
  background: var(--bg);
  padding: 80px 0 32px;
  border-top: 1px solid var(--border);
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 64px;
}
@media (max-width: 900px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 600px) { .footer-grid { grid-template-columns: 1fr; gap: 32px; } }
.footer-brand p {
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.65;
  margin-top: 20px;
  max-width: 340px;
}
.footer-col h4 {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--text-muted);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 18px;
}
.footer-col a {
  display: block;
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 12px;
  transition: color 0.2s;
}
.footer-col a:hover { color: var(--accent); }
.footer-bottom {
  padding-top: 32px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 32px;
  flex-wrap: wrap;
}
.footer-legal {
  font-family: var(--mono);
  font-size: 10px;
  color: var(--text-dim);
  letter-spacing: 0.04em;
  line-height: 1.8;
  max-width: 760px;
}
.footer-legal-title {
  color: var(--text-secondary);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 6px;
  display: block;
}
.footer-copy {
  font-family: var(--mono);
  font-size: 10px;
  color: var(--text-dim);
  letter-spacing: 0.1em;
  white-space: nowrap;
}

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .flow-line, .node-pulse, .fade-in { animation: none; }
}