/* ─── Site navigation bar — injected into calculator pages ───────────────────
   Uses --sn-* variables to avoid collisions with calculator own CSS vars.
   body padding-top override ensures content clears the fixed bar.
   ─────────────────────────────────────────────────────────────────────────── */
@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@700&family=Inter:wght@400;500&display=swap');

:root {
  --sn-h: 62px;
  --sn-bg: rgba(3,7,15,.0);
  --sn-bg-s: rgba(3,7,15,.88);
  --sn-cyan: #00d4ff;
  --sn-text: #94a3b8;
  --sn-text-h: #e8edf5;
  --sn-border: rgba(0,212,255,.12);
  --sn-t: .3s cubic-bezier(.4,0,.2,1);
}

body { padding-top: calc(var(--sn-h) + 20px) !important; }

#site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--sn-h);
  background: var(--sn-bg);
  backdrop-filter: blur(0);
  -webkit-backdrop-filter: blur(0);
  transition: background var(--sn-t), backdrop-filter var(--sn-t), box-shadow var(--sn-t);
  z-index: 9999;
}
#site-nav.scrolled {
  background: var(--sn-bg-s);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  box-shadow: 0 1px 0 var(--sn-border);
}

.sn-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
}

.sn-logo {
  font-family: 'Space Grotesk', 'Segoe UI', sans-serif;
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -.03em;
  color: var(--sn-text-h);
  text-decoration: none;
}
.sn-logo span { color: var(--sn-cyan); }

#sn-links {
  display: flex;
  align-items: center;
  gap: 2px;
  list-style: none;
  margin: 0; padding: 0;
}
#sn-links a {
  padding: 6px 10px;
  border-radius: 6px;
  font-family: 'Inter', 'Segoe UI', sans-serif;
  font-size: .82rem;
  font-weight: 500;
  color: var(--sn-text);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--sn-t), background var(--sn-t);
}
#sn-links a:hover { color: var(--sn-text-h); background: rgba(255,255,255,.06); }
#sn-links a.sn-active { color: var(--sn-cyan); background: rgba(0,212,255,.06); }

/* Burger */
#sn-burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  border: none;
  background: transparent;
}
#sn-burger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--sn-text-h);
  border-radius: 1px;
  transition: var(--sn-t);
}
#sn-burger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
#sn-burger.open span:nth-child(2) { opacity: 0; }
#sn-burger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

@media (max-width: 1024px) {
  #sn-burger { display: flex; }
  #sn-links {
    position: fixed;
    inset: var(--sn-h) 0 0 0;
    background: rgba(3,7,15,.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 6px;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--sn-t);
  }
  #sn-links.open { opacity: 1; pointer-events: all; }
  #sn-links a { font-size: 1.1rem; padding: 12px 28px; }
}