/* ============================================================
   Inhabit — design system
   Dark, technical, precise. 8px base grid. One accent.
   ============================================================ */

:root {
  /* color */
  --bg:        #0a0a0b;
  --bg-soft:   #101012;
  --text:      #f4f4f3;
  --text-mut:  #a1a1a6;
  --text-dim:  #6b6b72;
  --line:      rgba(255, 255, 255, 0.08);
  --line-2:    rgba(255, 255, 255, 0.14);
  --accent:    #5b8cff;        /* restrained electric blue */
  --accent-dim: rgba(91, 140, 255, 0.14);

  /* type scale (1.25 modular, fluid) */
  --fs-eyebrow: 0.78rem;
  --fs-body:    1.0625rem;
  --fs-lead:    clamp(1.125rem, 1.6vw, 1.4rem);
  --fs-h3:      1.375rem;
  --fs-h2:      clamp(1.9rem, 4.2vw, 3.1rem);
  --fs-display: clamp(4rem, 16vw, 11rem);

  /* spacing — 8px grid */
  --s1: 8px;  --s2: 16px; --s3: 24px; --s4: 32px;
  --s5: 48px; --s6: 64px; --s7: 96px; --s8: 128px; --s9: 160px;

  --maxw: 1200px;
  --radius: 14px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", system-ui, -apple-system, sans-serif;
  font-size: var(--fs-body);
  line-height: 1.6;
  letter-spacing: -0.011em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

h1, h2, h3 {
  font-family: "Space Grotesk", "Inter", sans-serif;
  font-weight: 600;
  margin: 0;
  letter-spacing: -0.03em;
  line-height: 1.05;
}

p { margin: 0; }

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

.wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--s3);
}

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

.skip-link {
  position: absolute; left: -9999px; top: 0;
  background: var(--accent); color: #061227;
  padding: var(--s1) var(--s2); border-radius: 0 0 8px 0; z-index: 100;
}
.skip-link:focus { left: 0; }

/* ---------- eyebrow ---------- */
.eyebrow {
  font-size: var(--fs-eyebrow);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-dim);
  font-weight: 500;
  margin-bottom: var(--s3);
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: var(--s1);
  font-family: "Space Grotesk", sans-serif;
  font-size: 0.95rem; font-weight: 500;
  padding: 0.75rem 1.35rem;
  border-radius: 10px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.25s var(--ease), background 0.25s var(--ease),
              border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}
.btn--primary {
  background: var(--accent); color: #06122b;
  font-weight: 600;
}
.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 30px -10px rgba(91, 140, 255, 0.6);
}
.btn--ghost {
  background: transparent; color: var(--text);
  border-color: var(--line-2);
}
.btn--ghost:hover {
  border-color: var(--accent);
  background: var(--accent-dim);
  transform: translateY(-2px);
}

/* ============================================================
   NAV
   ============================================================ */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 50;
  transition: background 0.3s var(--ease), border-color 0.3s var(--ease),
              backdrop-filter 0.3s var(--ease);
  border-bottom: 1px solid transparent;
}
.nav.is-stuck {
  background: rgba(10, 10, 11, 0.72);
  backdrop-filter: blur(14px) saturate(140%);
  border-bottom-color: var(--line);
}
.nav__inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 68px;
}
.nav__brand {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: "Space Grotesk", sans-serif;
  font-weight: 600; font-size: 1.15rem; letter-spacing: -0.02em;
}
.nav__mark {
  width: 11px; height: 11px; border-radius: 3px;
  background: var(--accent);
  box-shadow: 0 0 14px var(--accent);
}
.nav__links { display: flex; gap: var(--s4); }
.nav__links a {
  font-size: 0.92rem; color: var(--text-mut);
  transition: color 0.2s var(--ease);
}
.nav__links a:hover { color: var(--text); }
.nav__cta { padding: 0.5rem 0.95rem; }

/* ============================================================
   HERO
   ============================================================ */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex; flex-direction: column; justify-content: center;
  padding-top: 68px;
  overflow: hidden;
}
.hero__bg { position: absolute; inset: 0; z-index: 0; pointer-events: none; }

.hero__glow {
  position: absolute; top: 8%; right: 4%;
  width: 60vw; height: 60vw; max-width: 760px; max-height: 760px;
  background: radial-gradient(circle at 50% 50%,
    rgba(91, 140, 255, 0.18), rgba(91, 140, 255, 0.04) 42%, transparent 68%);
  filter: blur(10px);
  animation: drift 18s var(--ease) infinite alternate;
}
@keyframes drift {
  0%   { transform: translate(0, 0) scale(1); }
  100% { transform: translate(-4%, 5%) scale(1.08); }
}

.hero__grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 90% 70% at 70% 35%, #000 10%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 90% 70% at 70% 35%, #000 10%, transparent 75%);
  opacity: 0.6;
}

/* wireframe arm */
.arm {
  position: absolute;
  top: 50%; right: -2%;
  transform: translateY(-52%);
  width: min(46vw, 560px); height: auto;
  opacity: 0.92;
}
/* transform-box: view-box keeps transform-origin in viewBox coordinates,
   so the pivots land exactly on the joints. */
.arm__sway {
  transform-box: view-box;
  transform-origin: 150px 430px;     /* base joint */
  animation: sway 12s ease-in-out infinite alternate;
}
.arm__grip {
  transform-box: view-box;
  transform-origin: 348px 264px;     /* wrist joint */
  animation: grip 7s ease-in-out infinite alternate;
}

@keyframes sway { 0% { transform: rotate(-3deg); } 100% { transform: rotate(4deg); } }
@keyframes grip { 0% { transform: rotate(-7deg); } 100% { transform: rotate(9deg); } }

.arm__target { animation: pulse 3s ease-in-out infinite; }
.arm__target-ring { opacity: 0.5; animation: ring 3s ease-in-out infinite; transform-box: view-box; transform-origin: 430px 186px; }
@keyframes pulse { 0%, 100% { opacity: 0.5; } 50% { opacity: 1; } }
@keyframes ring  { 0%, 100% { opacity: 0.15; transform: scale(0.8); } 50% { opacity: 0.5; transform: scale(1.15); } }

.hero__inner { position: relative; z-index: 2; }
.hero__title {
  font-size: var(--fs-display);
  font-weight: 700;
  letter-spacing: -0.05em;
  line-height: 0.9;
  margin: var(--s2) 0 var(--s3);
  background: linear-gradient(180deg, #ffffff 30%, #c8c8cf 100%);
  -webkit-background-clip: text; background-clip: text;
  color: transparent;
}
.hero__tagline {
  font-family: "Space Grotesk", sans-serif;
  font-size: var(--fs-lead);
  font-weight: 500;
  color: var(--text);
  max-width: 22ch;
  margin-bottom: var(--s3);
}
.hero__sub {
  color: var(--text-mut);
  max-width: 48ch;
  margin-bottom: var(--s5);
}
.hero__cta { display: flex; flex-wrap: wrap; gap: var(--s2); }

.hero__scroll {
  position: absolute; bottom: var(--s4); left: 50%; transform: translateX(-50%);
  z-index: 2;
  display: flex; flex-direction: column; align-items: center; gap: var(--s2);
  font-size: 0.7rem; letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--text-dim);
}
.hero__scroll-line {
  width: 1px; height: 40px;
  background: linear-gradient(var(--accent), transparent);
  animation: scrollPulse 2.4s ease-in-out infinite;
}
@keyframes scrollPulse { 0%, 100% { opacity: 0.3; transform: scaleY(0.7); } 50% { opacity: 1; transform: scaleY(1); } }

/* ============================================================
   SECTIONS
   ============================================================ */
.section { padding-block: var(--s9); position: relative; }
.section + .section { border-top: 1px solid var(--line); }

.section__head { margin-bottom: var(--s7); max-width: 720px; }
.section__title { font-size: var(--fs-h2); }

/* ---------- problem ---------- */
.problem__statement {
  font-size: var(--fs-h2);
  max-width: 18ch;
  margin-bottom: var(--s5);
}
.problem__body {
  font-size: var(--fs-lead);
  color: var(--text-mut);
  max-width: 56ch;
  line-height: 1.65;
}
.problem__body + .problem__body { margin-top: var(--s4); }

/* ---------- cards ---------- */
.cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
.card {
  position: relative;
  background: var(--bg);
  padding: var(--s5) var(--s4) var(--s4);
  min-height: 248px;
  display: flex; flex-direction: column;
  transition: background 0.3s var(--ease);
}
.card::before {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(420px circle at var(--mx, 50%) var(--my, 0%),
    var(--accent-dim), transparent 60%);
  opacity: 0; transition: opacity 0.4s var(--ease); pointer-events: none;
}
.card:hover { background: var(--bg-soft); }
.card:hover::before { opacity: 1; }
.card__num {
  font-family: "Space Grotesk", sans-serif;
  font-size: 0.85rem; color: var(--text-dim);
  letter-spacing: 0.1em; margin-bottom: var(--s4);
}
.card__title {
  font-size: var(--fs-h3); margin-bottom: var(--s2);
}
.card__body { color: var(--text-mut); font-size: 1rem; line-height: 1.6; }
.card__tag {
  margin-top: auto; padding-top: var(--s3);
  font-size: 0.72rem; letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--text-dim);
}

/* ---------- stats ---------- */
.stats {
  display: grid; grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
.stat {
  padding: var(--s5) var(--s4);
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.stat__value {
  font-family: "Space Grotesk", sans-serif;
  font-weight: 600;
  font-size: clamp(2.6rem, 5vw, 3.6rem);
  letter-spacing: -0.04em;
  line-height: 1;
  display: flex; align-items: baseline; gap: 6px;
}
.stat__unit {
  font-size: 0.9rem; font-weight: 500; letter-spacing: 0.02em;
  color: var(--accent);
}
.stat__label {
  margin-top: var(--s2);
  font-size: 0.92rem; color: var(--text-mut);
}

/* ---------- CTA band ---------- */
.cta-band {
  margin-top: var(--s8);
  display: flex; align-items: center; justify-content: space-between;
  gap: var(--s5); flex-wrap: wrap;
  padding: var(--s6);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    radial-gradient(600px circle at 0% 0%, var(--accent-dim), transparent 55%),
    var(--bg-soft);
}
.cta-band__text h3 { font-size: clamp(1.5rem, 3vw, 2rem); margin-bottom: var(--s1); }
.cta-band__text p { color: var(--text-mut); }

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  border-top: 1px solid var(--line);
  padding-block: var(--s7) var(--s5);
}
.footer__inner {
  display: flex; justify-content: space-between; gap: var(--s5);
  flex-wrap: wrap;
  padding-bottom: var(--s6);
}
.footer__tag { color: var(--text-mut); margin-top: var(--s2); max-width: 28ch; }
.footer__links { display: flex; gap: var(--s5); flex-wrap: wrap; align-items: flex-start; }
.footer__links a {
  color: var(--text-mut); font-size: 0.95rem;
  transition: color 0.2s var(--ease);
}
.footer__links a:hover { color: var(--accent); }
.footer__base {
  display: flex; justify-content: space-between; gap: var(--s3);
  flex-wrap: wrap;
  padding-top: var(--s5);
  border-top: 1px solid var(--line);
  font-size: 0.85rem; color: var(--text-dim);
}

/* ============================================================
   REVEAL (IntersectionObserver)
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  will-change: opacity, transform;
}
.reveal.is-visible { opacity: 1; transform: none; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 900px) {
  .nav__links { display: none; }
  .arm { opacity: 0.5; width: 70vw; right: -12%; }
  .hero__glow { opacity: 0.7; }
}

@media (max-width: 640px) {
  :root { --s9: 96px; --s8: 80px; --s7: 64px; }
  .wrap { padding-inline: var(--s3); }
  .cards { grid-template-columns: 1fr; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .arm { opacity: 0.35; top: 14%; transform: none; right: -20%; width: 90vw; }
  .hero__sub { font-size: 1rem; }
  .cta-band { padding: var(--s4); }
  .footer__base { flex-direction: column; gap: var(--s1); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .reveal { opacity: 1; transform: none; }
}