/* ═══════════════════════════════════════════════════
   PROTEUS — Shared Design System
   Palette: black · charcoal · steel grey · blue · silver · white
   ═══════════════════════════════════════════════════ */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

:root {
  /* ── Backgrounds (near-black → charcoal) */
  --bg-void:    #000000;
  --bg-page:    #05060a;
  --bg-panel:   #0a0c12;
  --bg-surface: #10131c;
  --bg-raised:  #181c27;
  --bg-card:    #1d2130;

  /* ── Text (white → silver → grey) */
  --text-primary:   #f4f6ff;
  --text-secondary: #c0c8e0;
  --text-muted:     #7a85a0;
  --text-subtle:    #42495e;
  --text-ghost:     #282e3f;

  /* ── Blues (main accent family) */
  --blue-bright: #4f9fff;
  --blue-mid:    #2d6ecc;
  --blue-dim:    #1a3f7a;
  --blue-glow:   rgba(79, 159, 255, 0.18);
  --blue-glow-sm:rgba(79, 159, 255, 0.10);

  /* ── Silvers */
  --silver-light: #d0d8ec;
  --silver-mid:   #8898b8;
  --silver-dim:   #3a4260;

  /* ── Borders */
  --border:        rgba(255,255,255,0.07);
  --border-mid:    rgba(255,255,255,0.11);
  --border-bright: rgba(255,255,255,0.18);
  --border-blue:   rgba(79,159,255,0.25);

  /* ── Radius */
  --r-xs:   3px;
  --r-sm:   6px;
  --r-md:   10px;
  --r-lg:   16px;
  --r-xl:   22px;
  --r-pill: 9999px;

  /* ── Fonts */
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;
  --font-serif: 'Georgia', 'Times New Roman', serif;

  /* ── Shadows */
  --shadow-card: 0 4px 32px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.05);
  --shadow-blue: 0 0 40px rgba(79,159,255,0.15);
}

body {
  background: var(--bg-page);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

/* ─── CONTAINERS ─── */
.container        { max-width: 1160px; margin: 0 auto; padding: 0 36px; }
.container-narrow { max-width: 760px;  margin: 0 auto; padding: 0 36px; }
.container-wide   { max-width: 1320px; margin: 0 auto; padding: 0 36px; }

/* ─── BUTTONS ─── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  border: none;
  cursor: pointer;
  font-family: var(--font-sans);
  font-weight: 500;
  transition: all 0.2s ease;
  white-space: nowrap;
  text-decoration: none;
  letter-spacing: 0.01em;
}
.btn-sm  { padding: 7px 16px;  font-size: 13px; border-radius: var(--r-sm); }
.btn-md  { padding: 10px 22px; font-size: 14px; border-radius: var(--r-md); }
.btn-lg  { padding: 13px 30px; font-size: 15px; border-radius: var(--r-md); }
.btn-xl  { padding: 15px 38px; font-size: 16px; border-radius: var(--r-lg); }

.btn-primary {
  background: var(--blue-mid);
  color: #fff;
  box-shadow: 0 0 24px rgba(45,110,204,0.35);
}
.btn-primary:hover {
  background: var(--blue-bright);
  box-shadow: 0 0 36px rgba(79,159,255,0.45);
  transform: translateY(-1px);
}

.btn-ghost {
  background: rgba(255,255,255,0.05);
  color: var(--text-secondary);
  border: 1px solid var(--border);
}
.btn-ghost:hover {
  background: rgba(255,255,255,0.09);
  color: var(--text-primary);
  border-color: var(--border-mid);
}

.btn-silver {
  background: transparent;
  color: var(--silver-light);
  border: 1px solid var(--silver-dim);
}
.btn-silver:hover {
  background: rgba(208,216,236,0.07);
  border-color: var(--silver-mid);
  color: #fff;
}

/* ─── TAGS / PILLS ─── */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border-radius: var(--r-pill);
  border: 1px solid var(--border);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
  background: rgba(255,255,255,0.03);
}
.tag .dot {
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--blue-bright);
  flex-shrink: 0;
}
.tag-blue {
  color: var(--blue-bright);
  border-color: rgba(79,159,255,0.28);
  background: rgba(79,159,255,0.06);
}
.tag-silver {
  color: var(--silver-light);
  border-color: rgba(208,216,236,0.2);
  background: rgba(208,216,236,0.04);
}

/* ─── NAV ─── */
nav.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 200;
  background: rgba(5,6,10,0.82);
  backdrop-filter: blur(22px) saturate(1.3);
  -webkit-backdrop-filter: blur(22px) saturate(1.3);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 62px;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 19px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.025em;
}
.nav-logo svg { width: 30px; height: 30px; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}
.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.18s;
  position: relative;
}
.nav-links a:hover { color: var(--text-primary); }
.nav-links a.active {
  color: var(--text-primary);
}
.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -4px; left: 0; right: 0;
  height: 1px;
  background: var(--blue-bright);
  border-radius: 1px;
}
.nav-actions { display: flex; align-items: center; gap: 10px; }

/* ─── SECTION HELPERS ─── */
.section    { padding: 96px 0; }
.section-lg { padding: 120px 0; }
.section-sm { padding: 60px 0; }

.section-header { text-align: center; margin-bottom: 64px; }
.section-eyebrow {
  display: inline-block;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--blue-bright);
  margin-bottom: 14px;
}
.section-title {
  font-size: clamp(26px, 4vw, 42px);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--text-primary);
  margin-bottom: 14px;
}
.section-subtitle {
  font-size: 16px;
  line-height: 1.75;
  color: var(--text-muted);
  max-width: 540px;
  margin: 0 auto;
}

/* ─── DIVIDERS ─── */
.divider {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-mid) 30%, var(--border-mid) 70%, transparent);
}
.divider-blue {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--blue-dim) 30%, var(--blue-dim) 70%, transparent);
}

/* ─── FOOTER ─── */
footer.site-footer {
  background: var(--bg-void);
  border-top: 1px solid var(--border);
  padding: 64px 0 36px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}
.footer-brand .logo { margin-bottom: 14px; }
.footer-brand p {
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-muted);
  max-width: 280px;
}
.footer-col h4 {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-subtle);
  margin-bottom: 18px;
}
.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: 11px; }
.footer-col ul li a {
  font-size: 14px;
  color: var(--text-muted);
  transition: color 0.18s;
}
.footer-col ul li a:hover { color: var(--text-primary); }
.footer-bottom {
  padding-top: 26px;
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.footer-bottom p { font-size: 13px; color: var(--text-subtle); }
.footer-mono {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-ghost);
  letter-spacing: 0.06em;
}

/* ─── RESPONSIVE ─── */
@media (max-width: 900px) {
  .nav-links { display: none; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
}
@media (max-width: 600px) {
  .container, .container-narrow { padding: 0 20px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: 8px; text-align: center; }
}