/* ============================================================
   POLARIZE — Bioelectricity
   Dark, cinematic, documentary-grade. NatGeo/History x modern.
   ============================================================ */

:root {
  --bg:        #06080c;
  --bg-2:      #0a0e15;
  --panel:     #0e131c;
  --line:      rgba(255,255,255,.08);
  --ink:       #eef1f5;
  --ink-soft:  #9aa3b2;
  --ink-faint: #5a6373;

  --gold:      #ffffff;
  --gold-deep: #e0e0e0;
  --cyan:      #3fe0ff;   /* polarized / resting */
  --cyan-deep: #1aa6c9;
  --warm:      #ff7a3c;   /* depolarized */
  --magenta:   #ff4d8d;   /* anions */

  --maxw: 1180px;
  --ease: cubic-bezier(.16,.84,.34,1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Familjen Grotesk", sans-serif;
  font-size: 18px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

::selection { background: var(--gold); color: var(--bg); }

/* ---------- Type ---------- */
.kicker {
  font-family: "Familjen Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .32em;
  font-size: .72rem;
  font-weight: 600;
  color: var(--gold);
  margin: 0 0 1.4rem;
}

.h2 {
  font-family: "Familjen Grotesk", sans-serif;
  font-weight: 800;
  font-size: clamp(2rem, 5vw, 3.4rem);
  line-height: 1.02;
  letter-spacing: -.02em;
  margin: 0 0 1.4rem;
}
.h2 em, .hero__title em {
  font-style: normal;
  color: var(--gold);
}

p { margin: 0 0 1.15rem; color: var(--ink-soft); }
p strong { color: var(--ink); font-weight: 600; }
p em { color: var(--cyan); font-style: italic; }
.data { color: var(--gold); font-weight: 500; white-space: nowrap; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: .5em;
  font-family: "Familjen Grotesk", sans-serif;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .12em;
  font-size: .82rem;
  text-decoration: none;
  padding: .85em 1.6em;
  border-radius: 2px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .25s var(--ease), background .25s, color .25s, box-shadow .25s;
}
.btn--gold {
  background: var(--gold);
  color: var(--bg);
  box-shadow: 0 0 0 rgba(255,255,255,0);
}
.btn--gold:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 34px -8px rgba(255,255,255,.25);
}
.btn--ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line);
}
.btn--ghost:hover { border-color: var(--gold); color: var(--gold); }

/* ---------- Nav ---------- */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.1rem clamp(1.2rem, 4vw, 3rem);
  background: linear-gradient(to bottom, rgba(6,8,12,.9), rgba(6,8,12,0));
  backdrop-filter: blur(2px);
}
.brand { display: inline-flex; align-items: center; gap: .6rem; text-decoration: none; }
.brand__mark {
  width: 14px; height: 22px;
  background: var(--gold);
  border-radius: 1px;
  box-shadow: 0 0 18px -2px rgba(245,197,66,.7);
}
.brand__word {
  font-family: "Familjen Grotesk", sans-serif;
  font-weight: 800;
  letter-spacing: .18em;
  font-size: 1.05rem;
  color: var(--ink);
}
.nav__links { display: flex; gap: 2rem; }
.nav__links a {
  font-family: "Familjen Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .14em;
  font-size: .74rem;
  font-weight: 500;
  color: var(--ink-soft);
  text-decoration: none;
  transition: color .2s;
}
.nav__links a:hover { color: var(--gold); }
@media (max-width: 760px) { .nav__links { display: none; } }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: radial-gradient(120% 90% at 70% 10%, #0d1622 0%, var(--bg) 60%);
}
.hero__canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero__vignette {
  position: absolute; inset: 0;
  pointer-events: none;
  background:
    radial-gradient(80% 60% at 30% 50%, rgba(6,8,12,0) 0%, rgba(6,8,12,.55) 70%, var(--bg) 100%),
    linear-gradient(to right, rgba(6,8,12,.85) 0%, rgba(6,8,12,.2) 45%, rgba(6,8,12,0) 70%);
}
.hero__inner {
  position: relative;
  z-index: 2;
  max-width: var(--maxw);
  width: 100%;
  margin: 0 auto;
  padding: 0 clamp(1.2rem, 4vw, 3rem);
}
.hero__title {
  font-family: "Familjen Grotesk", sans-serif;
  font-weight: 800;
  font-size: clamp(3.2rem, 11vw, 8.5rem);
  line-height: .92;
  letter-spacing: -.03em;
  margin: 0 0 1.6rem;
  max-width: 14ch;
  text-shadow: 0 6px 50px rgba(0,0,0,.6);
}
.hero__lede {
  max-width: 46ch;
  font-size: clamp(1.05rem, 1.6vw, 1.3rem);
  color: var(--ink-soft);
}
.hero__lede strong { color: var(--gold); font-weight: 500; }
.hero__cta { display: flex; gap: 1rem; margin-top: 2.2rem; flex-wrap: wrap; }
.hero__scroll {
  position: absolute;
  bottom: 1.7rem; left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  font-family: "Familjen Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .3em;
  font-size: .66rem;
  color: var(--ink-faint);
  animation: bob 2.6s var(--ease) infinite;
}
@keyframes bob { 0%,100%{ transform: translate(-50%,0); opacity:.5 } 50%{ transform: translate(-50%,7px); opacity:1 } }

/* ---------- Section shell ---------- */
.section {
  position: relative;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(5rem, 11vw, 9rem) clamp(1.2rem, 4vw, 3rem);
}
.section__rail {
  font-family: "Familjen Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .3em;
  font-size: .72rem;
  font-weight: 600;
  color: var(--gold);
  padding-bottom: .9rem;
  margin-bottom: 2.8rem;
  border-bottom: 1px solid var(--line);
}

/* ---------- Concept ---------- */
.concept__grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: clamp(2rem, 5vw, 4.5rem);
  align-items: start;
}
.concept__lead p { font-size: 1.12rem; }
.stat-cards { list-style: none; margin: 0; padding: 0; display: grid; gap: 1rem; }
.stat-card {
  background: linear-gradient(160deg, var(--panel), #0a0d14);
  border: 1px solid var(--line);
  border-left: 3px solid var(--gold);
  padding: 1.3rem 1.4rem;
  border-radius: 3px;
}
.stat-card__num {
  display: block;
  font-family: "Familjen Grotesk", sans-serif;
  font-weight: 800;
  font-size: 2.6rem;
  line-height: 1;
  color: var(--ink);
  letter-spacing: -.02em;
}
.stat-card__num small { font-size: 1rem; color: var(--gold); margin-left: .15em; font-weight: 600; }
.stat-card__label {
  display: block;
  margin-top: .5rem;
  font-family: "Familjen Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .08em;
  font-size: .72rem;
  color: var(--ink-faint);
}
@media (max-width: 820px) { .concept__grid { grid-template-columns: 1fr; } }

/* ---------- Demo ---------- */
.demo__head { max-width: 62ch; margin-bottom: 2.4rem; }
.demo__head p { font-size: 1.08rem; }

.legend {
  display: inline-flex;
  align-items: center;
  gap: .4em;
  font-family: "Familjen Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .08em;
  font-size: .72rem;
  color: var(--ink-soft);
  white-space: nowrap;
}
.legend::before {
  content: "";
  width: 11px; height: 11px;
  border-radius: 50%;
  box-shadow: 0 0 10px currentColor;
}
.legend--na::before { background: var(--gold); color: var(--gold); }
.legend--k::before  { background: var(--cyan); color: var(--cyan); }
.legend--neg::before{ background: var(--magenta); color: var(--magenta); }
.legend--na { color: var(--gold); }
.legend--k  { color: var(--cyan); }
.legend--neg{ color: var(--magenta); }

.stage {
  position: relative;
  border: 1px solid var(--line);
  border-radius: 5px;
  overflow: hidden;
  background:
    radial-gradient(140% 100% at 50% -10%, #122033 0%, #070b11 65%);
  box-shadow: inset 0 0 80px rgba(0,0,0,.6);
}
.stage__canvas { display: block; width: 100%; height: 440px; }
@media (max-width: 640px){ .stage__canvas { height: 360px; } }

.stage__voltbadge {
  position: absolute;
  top: 1rem; right: 1rem;
  text-align: right;
  background: rgba(6,9,14,.6);
  border: 1px solid var(--line);
  border-radius: 3px;
  padding: .55rem .85rem;
  backdrop-filter: blur(4px);
}
.stage__voltlabel {
  display: block;
  font-family: "Familjen Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .14em;
  font-size: .58rem;
  color: var(--ink-faint);
}
.stage__voltval {
  font-family: "Familjen Grotesk", sans-serif;
  font-weight: 800;
  font-size: 1.5rem;
  color: var(--cyan);
  transition: color .12s;
}

.demo__controls {
  display: flex;
  align-items: center;
  gap: 1.2rem;
  flex-wrap: wrap;
  margin-top: 1.4rem;
}
.legend-row { display: flex; gap: 1.4rem; flex-wrap: wrap; margin-left: auto; }
@media (max-width: 640px){ .legend-row { margin-left: 0; } }

.trace { margin: 2.2rem 0 0; }
.trace__cap {
  font-family: "Familjen Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .18em;
  font-size: .68rem;
  color: var(--ink-faint);
  margin-bottom: .7rem;
}
.trace__canvas {
  display: block;
  width: 100%;
  height: 180px;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: linear-gradient(180deg, #0a0e15, #070a0f);
}

/* ---------- Signal ---------- */
.signal__grid {
  display: grid;
  grid-template-columns: 1fr 1.05fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
}
.signal__copy p { font-size: 1.1rem; }
.pull {
  margin: 2rem 0 0;
  padding-left: 1.3rem;
  border-left: 3px solid var(--gold);
  font-family: "Familjen Grotesk", sans-serif;
  font-style: italic;
  font-size: 1.3rem;
  line-height: 1.5;
  color: var(--ink);
}
.signal__viz {
  border: 1px solid var(--line);
  border-radius: 5px;
  overflow: hidden;
  background: radial-gradient(120% 120% at 50% 0%, #101a26, #070a0f);
}
.signal__canvas { display: block; width: 100%; height: 340px; }
@media (max-width: 820px) { .signal__grid { grid-template-columns: 1fr; } }

/* ---------- Scale ---------- */
.scale__title { max-width: 16ch; }
.scale__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.2rem;
  margin-top: 1rem;
}
.domain {
  border-top: 2px solid var(--gold);
  padding-top: 1.2rem;
}
.domain h3 {
  font-family: "Familjen Grotesk", sans-serif;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .06em;
  font-size: 1rem;
  margin: 0 0 .6rem;
  color: var(--ink);
}
.domain p { font-size: .98rem; color: var(--ink-soft); margin: 0; }
@media (max-width: 900px) { .scale__grid { grid-template-columns: repeat(2,1fr); gap: 2rem; } }
@media (max-width: 480px) { .scale__grid { grid-template-columns: 1fr; } }

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--line);
  text-align: center;
  padding: 4rem 1.5rem 5rem;
  background: var(--bg-2);
}
.footer__brand { display: inline-flex; align-items: center; gap: .6rem; margin-bottom: 1rem; }
.footer__tag {
  font-family: "Familjen Grotesk", sans-serif;
  font-style: italic;
  font-size: 1.25rem;
  color: var(--ink);
  margin: 0 0 .8rem;
}
.footer__fine {
  font-family: "Familjen Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .14em;
  font-size: .68rem;
  color: var(--ink-faint);
  margin: 0;
}

/* ---------- Reveal on scroll ---------- */
.section { opacity: 0; transform: translateY(28px); transition: opacity .9s var(--ease), transform .9s var(--ease); }
.section.in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .section { opacity: 1; transform: none; transition: none; }
  .hero__scroll { animation: none; }
}