/* Helix — "two strands" landing. Scroll-driven stages pin with position: sticky; main.js drives them. */
@font-face { font-family: "Satoshi"; src: url("assets/fonts/Satoshi-Medium.otf") format("opentype"); font-weight: 500; font-display: swap; }
@font-face { font-family: "Satoshi"; src: url("assets/fonts/Satoshi-Bold.otf") format("opentype"); font-weight: 700; font-display: swap; }

:root {
  --night: #040826;
  --night-2: #0a1446;
  --text: #eef1ff;
  --muted: #a3acd3;
  --dim: #6d77a3;
  --line: rgba(170, 190, 255, 0.14);
  --blue: #2f6bff;
  --cyan: #3ee8de;
  --coral: #ff7f74;
  --accent: linear-gradient(100deg, #9cbcff 0%, #3ee8de 100%);

  --sans: "Satoshi", -apple-system, "Segoe UI", sans-serif;
  --serif: "Fraunces", Georgia, "Times New Roman", serif;
  --ease: cubic-bezier(0.2, 0.7, 0.1, 1);
  --nav-h: 68px;
}

* { box-sizing: border-box; }
html { scroll-padding-top: var(--nav-h); -webkit-text-size-adjust: 100%; background: var(--night); }
body { margin: 0; background: var(--night); color: var(--text); font: 500 17px/1.6 var(--sans); -webkit-font-smoothing: antialiased; overflow-x: clip; }
img, canvas { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }
h1, h2, h3, p, ol, ul, figure { margin: 0; padding: 0; }
ol, ul { list-style: none; }
::selection { background: var(--cyan); color: var(--night); }
:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; border-radius: 4px; }

.wrap { max-width: 1320px; margin: 0 auto; padding: 0 40px; }
@media (max-width: 900px) { .wrap { padding: 0 24px; } }
@media (max-width: 600px) { .wrap { padding: 0 16px; } }

.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }

/* Accent words: italic serif with the brand gradient */
em { font-family: var(--serif); font-style: italic; font-weight: 400; letter-spacing: -0.02em; background: var(--accent); -webkit-background-clip: text; background-clip: text; color: transparent; padding-right: 0.06em; }

.h2 { font: 700 clamp(38px, 5.2vw, 76px)/1 var(--sans); letter-spacing: -0.04em; }
.lede { font-size: clamp(17px, 1.35vw, 20px); line-height: 1.55; color: var(--muted); max-width: 42ch; }

.btn { display: inline-flex; align-items: center; gap: 10px; padding: 14px 22px; border-radius: 999px; background: var(--text); color: var(--night); font: 700 16px/1 var(--sans); white-space: nowrap; transition: background 0.25s, transform 0.25s var(--ease), box-shadow 0.25s; }
.btn:hover { background: #fff; transform: translateY(-1px); box-shadow: 0 10px 40px -10px rgba(62, 232, 222, 0.6); }
.btn--sm { padding: 10px 16px; font-size: 14px; }
.btn--lg { padding: 18px 28px; font-size: 17px; }
.arr { display: inline-block; transition: transform 0.25s var(--ease); }
.btn:hover .arr { transform: translateX(4px); }

/* ---------- reveal ---------- */
.rv { opacity: 0; transform: translateY(28px); transition: opacity 0.9s var(--ease), transform 0.9s var(--ease); }
.rv.is-in { opacity: 1; transform: none; }

/* ---------- nav ---------- */
.nav { position: fixed; inset: 0 0 auto; z-index: 50; height: var(--nav-h); transition: background 0.3s, backdrop-filter 0.3s; }
.nav.is-stuck { background: rgba(4, 8, 38, 0.72); backdrop-filter: blur(14px) saturate(1.4); -webkit-backdrop-filter: blur(14px) saturate(1.4); }
.nav__in { height: 100%; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.nav__logo img { height: 26px; width: auto; }
.nav__links { display: flex; gap: 30px; font-size: 15px; color: var(--muted); }
.nav__links a { transition: color 0.2s; }
.nav__links a:hover { color: var(--text); }
.nav__progress { position: absolute; left: 0; bottom: 0; height: 2px; width: 100%; background: var(--accent); transform-origin: left; transform: scaleX(var(--p, 0)); }
@media (max-width: 900px) { .nav__links { display: none; } }

/* ---------- hero ---------- */
.hero { position: relative; min-height: 100svh; display: flex; align-items: center; overflow: hidden; background: radial-gradient(90% 70% at 72% 50%, #0d1d6b 0%, transparent 70%), var(--night); }
.hero__helix { position: absolute; inset: 0; width: 100%; height: 100%; -webkit-mask-image: linear-gradient(90deg, transparent 18%, #000 62%); mask-image: linear-gradient(90deg, transparent 18%, #000 62%); }
@media (max-width: 760px) { .hero__helix { -webkit-mask-image: linear-gradient(90deg, transparent 20%, #000 75%); mask-image: linear-gradient(90deg, transparent 20%, #000 75%); } }
.hero__in { position: relative; z-index: 1; width: 100%; padding-top: var(--nav-h); will-change: transform, opacity; }
.hero__h1 { position: relative; z-index: 1; font: 700 clamp(58px, 10.4vw, 170px)/0.92 var(--sans); letter-spacing: -0.05em; }
.hero__l1, .hero__l2 { display: block; }
.hero__l1 { position: relative; width: fit-content; }
.hero__l2 { overflow: clip; overflow-clip-margin: 0.2em; padding: 0 0.1em 0.12em 0; margin-top: -0.04em; }
.hero__l2 em { display: inline-block; font-size: 1.08em; letter-spacing: -0.035em; transform: translateY(110%); animation: rise 1.2s 1.3s var(--ease) forwards; }
/* "date." reads in full first, then a coral pen stroke slashes through it (replayed by main.js on return to the hero) */
.strike { position: relative; display: inline-block; animation: fade-out 0.7s 1.05s forwards; }
.strike::after { content: ""; position: absolute; left: -4%; right: -4%; top: 54%; height: 0.08em; border-radius: 99px; background: var(--coral); box-shadow: 0 0 0.3em rgba(255, 127, 116, 0.55); transform: scaleX(0) rotate(-3deg); transform-origin: left; animation: strike 0.75s 0.6s cubic-bezier(0.7, 0, 0.2, 1) forwards; }
.hero__lede { margin-top: clamp(24px, 4vh, 40px); max-width: 36ch; font-size: clamp(18px, 1.5vw, 22px); color: var(--muted); }
.hero__cta { margin-top: 32px; display: flex; align-items: center; gap: 14px 22px; flex-wrap: wrap; }
.hero__note { margin-top: 18px; font-size: clamp(18px, 1.5vw, 22px); color: var(--dim); }
.hero__lede, .hero__cta, .hero__note { opacity: 0; animation: up 1s 1.6s var(--ease) forwards; }
.hero__cta { animation-delay: 1.75s; }
.hero__note { animation-delay: 1.9s; }

/* large white Helix mark: rises in, strands draw down, base pairs pop then twinkle, the whole mark floats on a heartbeat glow */
/* anchored to the end of "date." and sized in em, so it tracks the headline at every width */
.hero__mark { position: absolute; left: calc(100% + 0.3em); top: -0.04em; width: 1.85em; aspect-ratio: 74 / 67; pointer-events: none; opacity: 0; animation: mark-in 1.6s 0.25s var(--ease) forwards; }
.hero__mark::before { content: ""; position: absolute; inset: -40%; background: radial-gradient(closest-side, rgba(62, 232, 222, 0.26), rgba(47, 107, 255, 0.14) 55%, transparent); animation: beat 2.8s 2.2s ease-in-out infinite; }
.hero__mark svg { position: relative; display: block; width: 100%; height: 100%; overflow: visible; filter: drop-shadow(0 0 22px rgba(156, 188, 255, 0.45)); animation: float 7s 2s ease-in-out infinite; }
.mk-strand { clip-path: inset(0 0 100% 0); animation: wipe 1.3s 0.8s var(--ease) forwards; }
.mk-dot { transform-box: fill-box; transform-origin: center; opacity: 0; animation: pop 0.5s calc(1.4s + var(--i) * 90ms) var(--ease) forwards, twinkle 3.6s calc(2.6s + var(--i) * 0.45s) ease-in-out infinite; }
@media (max-width: 760px) {
  .hero__h1 { margin-top: 112px; }
  .hero__l1 { position: static; }
  .hero__mark { left: 0; top: auto; bottom: calc(100% + 28px); width: 92px; }
}

@keyframes mark-in { from { opacity: 0; transform: translateY(24px) scale(0.84); filter: blur(10px); } to { opacity: 1; transform: none; filter: none; } }
@keyframes float { 50% { transform: translateY(-12px) rotate(-1.5deg); } }
@keyframes beat { 0%, 50%, 100% { transform: scale(1); opacity: 0.75; } 12% { transform: scale(1.1); opacity: 1; } 24% { transform: scale(1); } 36% { transform: scale(1.06); opacity: 1; } }
@keyframes wipe { to { clip-path: inset(0); } }
@keyframes pop { from { opacity: 0; transform: scale(0); } to { opacity: 1; transform: none; } }
@keyframes twinkle { 50% { opacity: 0.3; } }

/* store badges */
.stores { display: flex; flex-wrap: wrap; gap: 10px; }
.store { display: inline-flex; align-items: center; gap: 10px; height: 52px; padding: 0 18px 0 14px; border-radius: 12px; background: #000; color: #fff; border: 1px solid rgba(255, 255, 255, 0.3); transition: border-color 0.25s, transform 0.25s var(--ease); }
.store:hover { border-color: rgba(255, 255, 255, 0.75); transform: translateY(-1px); }
.store svg { flex: none; width: 24px; height: 24px; }
.store span { display: grid; font: 700 18px/1.05 var(--sans); letter-spacing: -0.01em; white-space: nowrap; }
.store small { font: 500 10.5px/1.25 var(--sans); letter-spacing: 0.02em; opacity: 0.85; }
.hero__cue { position: absolute; left: 50%; bottom: 28px; width: 1px; height: 56px; background: linear-gradient(var(--line), transparent); overflow: hidden; }
.hero__cue::after { content: ""; position: absolute; left: 0; top: -40%; width: 1px; height: 40%; background: var(--cyan); animation: cue 2.2s 2s var(--ease) infinite; }

@keyframes rise { to { transform: none; } }
@keyframes strike { to { transform: scaleX(1) rotate(-3deg); } }
@keyframes fade-out { to { color: rgba(238, 241, 255, 0.38); } }
@keyframes up { from { opacity: 0; transform: translateY(18px); } to { opacity: 1; transform: none; } }
@keyframes cue { to { top: 110%; } }

/* ---------- pinned stages ---------- */
.stage { position: relative; height: calc(100svh + var(--n) * var(--per, 70svh)); }
.stage__pin { position: sticky; top: 0; height: 100svh; overflow: hidden; display: flex; align-items: center; }
.stage__pin > .wrap { width: 100%; }

/* ---------- intent ---------- */
.intent { padding-top: clamp(100px, 16vh, 180px); }
.intro { display: grid; grid-template-columns: 1.2fr 1fr; gap: 40px 64px; align-items: end; }
.intent .stage { --per: 55svh; }
.intent__grid { display: grid; grid-template-columns: 1fr minmax(0, 0.85fr) auto; gap: 64px; align-items: center; padding-top: var(--nav-h); }
.reel__pre { display: block; font-size: clamp(18px, 1.6vw, 22px); color: var(--muted); margin-bottom: 6px; }
.reel__window { display: block; height: 1.2em; overflow: hidden; font: italic 400 clamp(42px, 6vw, 92px)/1.2 var(--serif); letter-spacing: -0.03em; }
.reel__track { display: block; will-change: transform; }
.reel__track > span { display: block; height: 1.2em; white-space: nowrap; background: var(--accent); -webkit-background-clip: text; background-clip: text; color: transparent; }
.intent__desc { position: relative; margin-top: 28px; height: 5em; max-width: 34ch; }
.intent__desc li { position: absolute; inset: 0 0 auto; color: var(--text); font-size: clamp(17px, 1.4vw, 20px); line-height: 1.5; will-change: transform, opacity; }
.intent__photos { position: relative; height: min(72svh, 680px); aspect-ratio: 2 / 3; justify-self: center; border-radius: 28px; overflow: hidden; background: var(--night-2); box-shadow: 0 40px 120px -40px rgba(47, 107, 255, 0.55); }
.intent__photos img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; will-change: clip-path, transform; }
.ticks { display: grid; gap: 10px; }
.ticks li { width: 3px; height: 28px; border-radius: 3px; background: var(--line); transition: background 0.4s, height 0.4s var(--ease); }
.ticks li.is-on { background: var(--cyan); height: 44px; }

/* ---------- future family ---------- */
.ff { position: relative; overflow: hidden; padding: clamp(110px, 16vh, 180px) 0; background: radial-gradient(55% 60% at 72% 50%, #0d1d6b 0%, transparent 70%), var(--night); }
.ff__grid { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; }
.ff__logo { width: min(100%, 420px); height: auto; margin-bottom: clamp(28px, 4.5vh, 48px); }
.ff__copy .lede { margin-top: 24px; }
.ff__copy .btn { margin-top: 36px; }
.ff__device { --ph: min(74svh, 660px); position: relative; justify-self: center; }
.ff__helix { position: absolute; left: 50%; top: 50%; width: calc(var(--ph) * 1.3); height: calc(var(--ph) * 1.3); max-width: none; transform: translate(-50%, -50%); pointer-events: none; -webkit-mask-image: linear-gradient(transparent, #000 20%, #000 80%, transparent); mask-image: linear-gradient(transparent, #000 20%, #000 80%, transparent); }
.ff__chips { position: absolute; inset: 0; z-index: 2; pointer-events: none; }
.ff__chips li { position: absolute; display: grid; gap: 4px; padding: 12px 18px; border-radius: 18px; background: rgba(10, 20, 70, 0.62); border: 1px solid rgba(156, 188, 255, 0.28); -webkit-backdrop-filter: blur(12px); backdrop-filter: blur(12px); box-shadow: 0 20px 50px -20px rgba(0, 0, 0, 0.7); font: 700 clamp(16px, 1.4vw, 20px)/1.1 var(--sans); white-space: nowrap; opacity: 0; translate: 0 18px; transition: opacity 0.8s var(--ease), translate 0.8s var(--ease); animation: bob 6s ease-in-out infinite; }
.ff__chips span { font: 500 12px/1 var(--sans); letter-spacing: 0.12em; text-transform: uppercase; color: var(--cyan); }
.ff__chips li:nth-child(1) { top: 16%; left: -44%; }
.ff__chips li:nth-child(2) { top: 44%; right: -46%; animation-delay: -2s; transition-delay: 0.45s; }
.ff__chips li:nth-child(3) { bottom: 22%; left: -46%; animation-delay: -4s; transition-delay: 0.7s; }
.ff__device.is-in .ff__chips li { opacity: 1; translate: none; }
@keyframes bob { 50% { transform: translateY(-8px); } }

/* ---------- story (phone) ---------- */
.story .stage { --per: 65svh; }
.story__grid { display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 56px; padding-top: var(--nav-h); }
.story__copy { position: relative; z-index: 3; height: 300px; }
.chap { position: absolute; inset: 50% 0 auto; transform: translateY(-50%); will-change: transform, opacity; }
.chap h3 { font: 700 clamp(36px, 4.2vw, 64px)/1.02 var(--sans); letter-spacing: -0.04em; }
.chap p { margin-top: 18px; color: var(--muted); font-size: clamp(17px, 1.3vw, 19px); max-width: 32ch; }

.story__device { --ph: min(76svh, 700px); position: relative; }
.story__helix { position: absolute; left: 50%; top: 50%; width: calc(var(--ph) * 1.25); height: 130svh; max-width: none; transform: translate(-50%, -50%); pointer-events: none; }
.story__helix--front { z-index: 2; }
.phone { position: relative; z-index: 1; height: var(--ph); width: calc(var(--ph) * 0.49); padding: calc(var(--ph) * 0.014); border-radius: calc(var(--ph) * 0.078); background: linear-gradient(160deg, #3a4060, #0c0f1d 40%, #1a1f33); box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.16), 0 50px 120px -30px rgba(47, 107, 255, 0.55), 0 0 0 1px rgba(0, 0, 0, 0.6); }
.phone__screen { position: relative; height: 100%; border-radius: calc(var(--ph) * 0.064); overflow: hidden; background: #fff; isolation: isolate; }
.phone__reel { height: 100%; will-change: transform; }
.slide { height: 100%; padding-top: calc(var(--ph) * 0.05); background: var(--top); }
.slide img { width: 100%; height: 100%; object-fit: cover; object-position: center top; }
.phone__time { position: absolute; top: calc(var(--ph) * 0.016); left: 12%; font: 700 calc(var(--ph) * 0.02)/1 var(--sans); color: #fff; mix-blend-mode: difference; }
.phone__island { position: absolute; top: calc(var(--ph) * 0.011); left: 50%; width: 30%; height: calc(var(--ph) * 0.036); transform: translateX(-50%); border-radius: 99px; background: #000; }

.story__nav { justify-self: end; display: grid; gap: 4px; }
.story__nav button { display: flex; align-items: center; gap: 14px; padding: 8px 0; font-size: 15px; color: var(--dim); text-align: left; transition: color 0.3s; }
.story__nav button::before { content: ""; width: 14px; height: 1px; background: currentColor; transition: width 0.4s var(--ease); }
.story__nav button:hover { color: var(--muted); }
.story__nav button.is-on { color: var(--text); }
.story__nav button.is-on::before { width: 36px; background: var(--cyan); }

/* ---------- genetics ---------- */
.cgt { padding: clamp(110px, 18vh, 200px) 0; background: linear-gradient(var(--night), var(--night-2) 50%, var(--night)); }
.cgt__grid { display: grid; grid-template-columns: 1fr 1fr; gap: 80px; align-items: center; }
.cgt .h2 { font-size: clamp(36px, 4.4vw, 64px); }
.cgt__copy .lede { margin-top: 24px; }
.cgt__partner { margin-top: 32px; display: flex; align-items: center; gap: 14px; flex-wrap: wrap; color: var(--muted); font-size: 15px; }
.cgt__logo { display: inline-flex; padding: 9px 14px; border-radius: 12px; background: #fff; }
.cgt__logo img { height: 22px; width: auto; }

.punnett { padding: clamp(20px, 3vw, 36px); border-radius: 32px; background: rgba(255, 255, 255, 0.035); border: 1px solid var(--line); }
.punnett__title { font-size: 14px; color: var(--muted); letter-spacing: 0.08em; text-transform: uppercase; }
.conds { margin-top: 14px; display: flex; flex-wrap: wrap; gap: 8px; }
.conds button { padding: 8px 13px; border-radius: 999px; border: 1px solid var(--line); background: rgba(255, 255, 255, 0.03); font-size: 14px; line-height: 1.2; color: var(--muted); transition: color 0.25s, background 0.25s, border-color 0.25s; }
.conds button:hover { color: var(--text); border-color: rgba(156, 188, 255, 0.4); }
.conds button[aria-pressed="true"] { color: var(--night); background: var(--text); border-color: var(--text); }
.conds__more { padding: 8px 4px; font-size: 14px; line-height: 1.2; color: var(--cyan); }
.punnett__parents { margin-top: 24px; display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.parent { display: flex; align-items: center; gap: 10px; padding: 14px 16px; border-radius: 18px; background: rgba(255, 255, 255, 0.05); border: 1px solid var(--line); text-align: left; transition: border-color 0.3s, background 0.3s; }
.parent > span { font-weight: 700; }
.parent__state { margin-right: auto; font-weight: 500; color: var(--muted); }
.parent[aria-pressed="true"] { border-color: rgba(255, 127, 116, 0.45); background: rgba(255, 127, 116, 0.08); }
.parent[aria-pressed="true"] .parent__state { color: var(--coral); }
.switch { position: relative; flex: none; width: 40px; height: 24px; border-radius: 99px; background: rgba(255, 255, 255, 0.14); transition: background 0.3s; }
.switch::after { content: ""; position: absolute; top: 3px; left: 3px; width: 18px; height: 18px; border-radius: 50%; background: #fff; transition: transform 0.35s var(--ease); }
.parent[aria-pressed="true"] .switch { background: var(--coral); }
.parent[aria-pressed="true"] .switch::after { transform: translateX(16px); }

.punnett__grid { margin-top: 22px; display: grid; grid-template-columns: 48px 1fr 1fr; grid-template-rows: 48px auto auto; gap: 10px; perspective: 800px; }
.allele { display: grid; place-items: center; align-self: center; justify-self: center; width: 40px; height: 40px; border-radius: 50%; font: 700 18px/1 var(--sans); border: 1.5px solid rgba(156, 188, 255, 0.5); color: #9cbcff; transition: all 0.4s var(--ease); }
.allele.is-a { border-color: var(--coral); color: var(--coral); background: rgba(255, 127, 116, 0.1); }
.child { display: grid; place-content: center; gap: 2px; min-height: clamp(92px, 11vw, 132px); border-radius: 20px; text-align: center; background: rgba(255, 255, 255, 0.04); border: 1px solid var(--line); transition: background 0.5s, border-color 0.5s, box-shadow 0.5s; }
.child b { font-size: clamp(22px, 2.4vw, 30px); letter-spacing: 0.02em; }
.child span { font-size: 13px; color: var(--muted); }
.child.is-car { background: rgba(255, 127, 116, 0.06); border-color: rgba(255, 127, 116, 0.25); }
.child.is-aff { background: rgba(255, 127, 116, 0.22); border-color: var(--coral); box-shadow: 0 0 50px -10px rgba(255, 127, 116, 0.6); }
.child.is-aff span { color: #ffd0cb; }
.child.flip { animation: flip 0.6s var(--ease) both; animation-delay: calc(var(--k) * 70ms); }
@keyframes flip { from { transform: rotateX(-90deg); opacity: 0; } to { transform: none; opacity: 1; } }
.punnett__verdict { margin-top: 22px; display: flex; align-items: baseline; gap: 14px; color: var(--muted); }
.punnett__verdict b { flex: none; font: 700 clamp(32px, 3.4vw, 46px)/1 var(--sans); letter-spacing: -0.03em; color: var(--text); }
.punnett__verdict.is-risk b { color: var(--coral); }

/* ---------- helper ---------- */
.helper .stage { height: 240svh; }
.helper__media { position: absolute; inset: 0; clip-path: inset(var(--iy, 16%) var(--ix, 28%) round var(--ir, 28px)); will-change: clip-path; }
.helper__media img { width: 100%; height: 100%; object-fit: cover; object-position: center 30%; transform: scale(var(--is, 1.18)); }
.helper__media::after { content: ""; position: absolute; inset: 0; background: linear-gradient(transparent 30%, rgba(4, 8, 38, 0.92)); opacity: var(--e, 0); }
.helper__head { position: relative; z-index: 1; align-self: flex-end; display: flex; justify-content: space-between; align-items: flex-end; gap: 40px; padding-bottom: clamp(48px, 10vh, 110px); opacity: var(--t, 0); transform: translateY(calc((1 - var(--t, 0)) * 40px)); }
.helper__h { font: 700 clamp(48px, 8vw, 128px)/0.95 var(--sans); letter-spacing: -0.05em; }
.helper__logo { flex: none; width: clamp(220px, 28vw, 440px); height: auto; margin-bottom: clamp(4px, 1vw, 14px); filter: drop-shadow(0 4px 24px rgba(4, 8, 38, 0.6)); }
.helper__body { display: grid; grid-template-columns: 1fr 1fr; gap: 40px 80px; padding-block: clamp(80px, 12vh, 130px); align-items: start; }
.helper__steps { counter-reset: s; grid-row: span 2; }
.helper__steps li { counter-increment: s; display: grid; grid-template-columns: 48px 1fr; padding: 22px 0; border-top: 1px solid var(--line); font-size: clamp(18px, 1.5vw, 21px); }
.helper__steps li::before { content: counter(s, decimal-leading-zero); color: var(--cyan); font-size: 14px; padding-top: 5px; }
.helper__body .btn { justify-self: start; }
.fine { grid-column: 1 / -1; max-width: 80ch; font-size: 13px; line-height: 1.6; color: var(--dim); }

/* ---------- FAQ ---------- */
.notes { padding: clamp(80px, 12vh, 140px) 0; border-top: 1px solid var(--line); }
.notes__grid { display: grid; grid-template-columns: 1fr 2fr; gap: 40px 80px; }
.notes__list details { border-bottom: 1px solid var(--line); }
.notes__list details:first-child { border-top: 1px solid var(--line); }
.notes__list summary { list-style: none; display: flex; justify-content: space-between; align-items: center; gap: 20px; padding: 24px 0; cursor: pointer; font: 700 clamp(19px, 1.6vw, 23px)/1.3 var(--sans); letter-spacing: -0.01em; }
.notes__list summary::-webkit-details-marker { display: none; }
.notes__list summary::after { content: "+"; flex: none; width: 34px; height: 34px; display: grid; place-items: center; border-radius: 50%; border: 1px solid var(--line); font-weight: 500; color: var(--muted); transition: transform 0.35s var(--ease), color 0.3s, border-color 0.3s; }
.notes__list details[open] summary::after { transform: rotate(45deg); color: var(--cyan); border-color: var(--cyan); }
.notes__list details p { padding: 0 50px 26px 0; color: var(--muted); max-width: 60ch; }

/* ---------- close ---------- */
.close { position: relative; min-height: 80svh; display: flex; align-items: center; overflow: hidden; text-align: center; background: radial-gradient(70% 60% at 50% 55%, #0d1d6b 0%, transparent 70%), var(--night); }
.close__helix { position: absolute; inset: 0; width: 100%; height: 100%; opacity: 0.8; }
.close__in { position: relative; z-index: 1; width: 100%; display: grid; justify-items: center; gap: 30px; }
.close__h { font: 700 clamp(52px, 9.5vw, 150px)/0.92 var(--sans); letter-spacing: -0.05em; }
.close__in p { color: var(--muted); font-size: 15px; max-width: 34ch; }
.close .stores { justify-content: center; margin-top: -12px; }

.foot { border-top: 1px solid var(--line); padding: 28px 0 calc(28px + env(safe-area-inset-bottom)); font-size: 13px; color: var(--dim); }
.foot__in { display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; }
.foot nav { display: flex; gap: 22px; }
.foot a:hover { color: var(--text); }

.dock { display: none; }

/* ---------- tablet / mobile ---------- */
@media (max-width: 960px) {
  .intro, .cgt__grid, .ff__grid, .helper__body, .notes__grid { grid-template-columns: 1fr; }
  .helper__steps { grid-row: auto; }
  .cgt__grid, .ff__grid { gap: 48px; }
  .ff__device { --ph: min(62svh, 560px); }
  .ff__chips li:nth-child(1) { left: -22%; }
  .ff__chips li:nth-child(2) { right: -24%; }
  .ff__chips li:nth-child(3) { left: -18%; }
  .helper__head { flex-direction: column-reverse; align-items: flex-start; gap: 22px; }
  .helper__logo { width: min(68vw, 320px); margin: 0; }

  .intent__grid { grid-template-columns: 1fr; gap: 24px; align-content: center; }
  .intent__photos { order: -1; height: 40svh; width: 100%; aspect-ratio: auto; border-radius: 22px; }
  .ticks { display: none; }
  .intent__desc { margin-top: 14px; height: 4.6em; }

  .story__grid { grid-template-columns: 1fr; gap: 20px; justify-items: center; }
  .story__device { --ph: min(56svh, 520px); }
  .story__helix { height: calc(var(--ph) * 1.12); }
  .story__device { order: -1; }
  .story__copy { width: 100%; height: 170px; }
  .chap { inset: 0 0 auto; }
  .chap h3 { font-size: clamp(30px, 8vw, 40px); }
  .chap p { margin-top: 10px; font-size: 16px; }
  .story__nav { display: none; }

  .dock { position: fixed; z-index: 40; left: 16px; right: 16px; bottom: calc(14px + env(safe-area-inset-bottom)); display: flex; justify-content: center; gap: 10px; padding: 16px; border-radius: 999px; background: var(--text); color: var(--night); font-weight: 700; box-shadow: 0 16px 40px -10px rgba(0, 0, 0, 0.6); transform: translateY(160%); transition: transform 0.45s var(--ease); }
  .dock.is-on { transform: none; }
}
@media (max-width: 600px) {
  .hero__in { padding-bottom: 40px; }
  .hero__cta .btn, .hero__cta .stores { width: 100%; justify-content: center; }
  .stores .store { flex: 1; justify-content: center; padding: 0 12px; }
  .close .stores { width: 100%; }
  .ff__chips li { padding: 9px 13px; border-radius: 14px; font-size: 15px; }
  .ff__chips span { font-size: 10.5px; }
  .ff__chips li:nth-child(1) { left: -14%; }
  .ff__chips li:nth-child(3) { display: none; }
  .ff__chips li:nth-child(2) { right: -14%; }
  .helper .stage { height: 200svh; }
  .parent { padding: 12px; gap: 8px; }
  .parent__state { font-size: 14px; }
  .switch { display: none; }
  .punnett__grid { grid-template-columns: 40px 1fr 1fr; grid-template-rows: 40px auto auto; }
  .allele { width: 34px; height: 34px; font-size: 16px; }
  .punnett__verdict { flex-direction: column; gap: 6px; }
  .notes__list details p { padding-right: 0; }
}
@media (max-height: 700px) and (max-width: 960px) {
  .intent__photos { height: 32svh; }
  .story__device { --ph: 50svh; }
}

@media (prefers-reduced-motion: reduce) {
  .hero__l2 em, .strike, .strike::after, .hero__lede, .hero__cta, .hero__note, .hero__mark, .mk-strand { animation-duration: 0.01s; animation-delay: 0s; }
  .hero__mark::before, .hero__mark svg, .ff__chips li { animation: none; }
  .mk-dot { animation: pop 0.01s forwards; }
  .hero__cue { display: none; }
  .rv { transition: none; opacity: 1; transform: none; }
  .child.flip { animation: none; }
}