/* "Learner field": a clean white page whose single color belongs to a different
   example learner on each visit. --hue is set by the script; 250 is the fallback.
   Fields use oklch L 0.52, which keeps white text readable at every hue. */
:root {
  --hue: 250;
  --field: oklch(0.52 0.12 var(--hue));
  --field-soft: oklch(0.96 0.02 var(--hue));
  --field-tint: oklch(0.90 0.04 var(--hue));
  --ink: #0e0f12;
  --grey: #5c6068;
  --hair: #e4e5e8;
  --panel: #f6f7f8;
  --bg: #ffffff;
  --radius: 18px;
  --sans: "Host Grotesk", "Segoe UI", system-ui, sans-serif;
  --mono: "Martian Mono", ui-monospace, "Cascadia Code", Consolas, monospace;
  color-scheme: light;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--ink); font-family: var(--sans); font-size: 17px; line-height: 1.6; -webkit-font-smoothing: antialiased; overflow-x: hidden; }
h1, h2, h3 { margin: 0; font-weight: 600; text-wrap: balance; }
h1 { font-size: clamp(2.6rem, 5.4vw, 4.5rem); line-height: 1.0; letter-spacing: -0.045em; }
h2 { font-size: clamp(2rem, 3.8vw, 3rem); line-height: 1.04; letter-spacing: -0.04em; max-width: 20ch; margin-bottom: 20px; }
h3 { font-size: 1.15rem; letter-spacing: -0.02em; line-height: 1.25; }
p { margin: 0 0 1em; text-wrap: pretty; }
a { color: inherit; }
.mono { font-family: var(--mono); font-stretch: 87.5%; font-size: 0.72rem; letter-spacing: 0.01em; color: var(--grey); }
:focus-visible { outline: 2px solid var(--ink); outline-offset: 3px; }
.container { width: 100%; max-width: 1160px; margin: 0 auto; padding: 0 16px; }
@media (min-width: 720px) { .container { padding: 0 40px; } }
.body { color: var(--grey); max-width: 62ch; }
.note { margin-top: 16px; }

.kicker { display: flex; align-items: center; gap: 8px; margin-bottom: 16px; }
.kicker i, .logo i { width: 9px; height: 9px; border-radius: 50%; background: var(--field); display: inline-block; flex: none; transition: background 0.6s; }

/* Draft bar + nav */
.topbar { font-family: var(--mono); font-stretch: 87.5%; font-size: 0.7rem; text-align: center; padding: 7px 16px; background: var(--panel); color: var(--grey); border-bottom: 1px solid var(--hair); }
.tag { background: var(--ink); color: #fff; padding: 1px 6px; border-radius: 3px; margin-right: 8px; text-transform: uppercase; letter-spacing: 0.06em; }
.nav { position: sticky; top: 0; z-index: 20; background: rgba(255,255,255,0.88); backdrop-filter: blur(12px); border-bottom: 1px solid var(--hair); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 66px; }
.nav nav { display: flex; align-items: center; gap: 26px; }
.nav nav a:not(.btn) { text-decoration: none; font-size: 0.92rem; color: var(--grey); }
.nav nav a:not(.btn):hover { color: var(--ink); }
@media (max-width: 760px) { .nav nav a:not(.btn) { display: none; } }
.logo { display: inline-flex; align-items: center; gap: 8px; text-decoration: none; font-weight: 700; font-size: 1.25rem; letter-spacing: -0.01em; }
.logo-small { font-size: 1rem; }

.btn { display: inline-flex; align-items: center; background: var(--ink); color: #fff; text-decoration: none; font-weight: 600; font-size: 0.95rem; padding: 12px 20px; border-radius: 999px; transition: transform 0.15s; }
.btn:hover { transform: translateY(-1px); }
.btn-ghost { background: transparent; color: var(--ink); box-shadow: inset 0 0 0 1px #c9cbd0; }
.btn-small { padding: 8px 16px; font-size: 0.85rem; }
.btn-large { padding: 16px 28px; font-size: 1.05rem; margin-top: 12px; }

/* Hero */
.hero { display: grid; gap: 36px; padding-top: 40px; padding-bottom: 96px; }
@media (min-width: 980px) { .hero { grid-template-columns: 1fr 1fr; gap: 48px; align-items: stretch; } }
.hero-copy { display: flex; flex-direction: column; justify-content: center; }
.lead { font-size: 1.15rem; color: var(--grey); max-width: 38ch; margin: 24px 0 0; }
.actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 32px; }
.field { background: var(--field); color: #fff; border-radius: 22px; padding: 24px; display: grid; grid-template-rows: auto 1fr auto; gap: 20px; min-height: 440px; min-width: 0; transition: background 0.6s; }
.field .mono { color: rgba(255,255,255,0.86); }
.field-head { display: flex; justify-content: space-between; align-items: center; gap: 10px; flex-wrap: wrap; }
.field-head b { color: #fff; font-weight: 500; }
.field button { color: #fff; background: rgba(255,255,255,0.14); border: 1px solid rgba(255,255,255,0.5); border-radius: 999px; padding: 6px 12px; cursor: pointer; }
.field button:hover { background: rgba(255,255,255,0.24); }
.print { display: grid; grid-template-columns: repeat(12, 1fr); gap: 8px; align-content: center; }
.print i { aspect-ratio: 1; border-radius: 50%; background: #fff; opacity: var(--o, 0.4); transition: opacity 0.6s; }
.field-foot { display: flex; justify-content: space-between; gap: 12px 20px; flex-wrap: wrap; }
.field-foot b { display: block; color: #fff; font-weight: 600; font-size: 1.05rem; }

/* Sections */
.section { padding: 96px 0; border-top: 1px solid var(--hair); }
.cols-2 { display: grid; gap: 8px 40px; max-width: 980px; }
@media (min-width: 860px) { .cols-2 { grid-template-columns: 1fr 1fr; } }
.compare { display: grid; gap: 20px; margin-top: 36px; }
@media (min-width: 900px) { .compare { grid-template-columns: 1fr 1fr; } }
.compare figure { margin: 0; background: var(--panel); border-radius: var(--radius); padding: 22px; }
.compare figcaption { margin-top: 14px; }
.dots { display: grid; grid-template-columns: repeat(10, 1fr); gap: 10px; }
.dots i { aspect-ratio: 1; border-radius: 50%; background: #c9ccd1; }
.stats { display: grid; margin-top: 40px; border-top: 1px solid var(--ink); }
@media (min-width: 860px) { .stats { grid-template-columns: repeat(3, 1fr); } }
.stat { display: flex; flex-direction: column; gap: 6px; padding: 20px 24px 20px 0; border-bottom: 1px solid var(--hair); min-width: 0; }
.stat b { font-weight: 600; font-size: 2.4rem; letter-spacing: -0.04em; line-height: 1.1; font-variant-numeric: tabular-nums; }
.stat span { color: var(--grey); font-size: 0.95rem; }
.stat a { margin-top: auto; padding-top: 8px; text-decoration: underline; text-decoration-color: var(--hair); text-underline-offset: 3px; overflow-wrap: anywhere; }
.stat a:hover { color: var(--ink); text-decoration-color: currentColor; }
.stat .step { color: var(--ink); margin-bottom: 4px; text-transform: uppercase; letter-spacing: 0.06em; }
.note-line { margin: 24px 0 0; font-size: 1.05rem; color: var(--ink); }
.versus { display: grid; gap: 16px; margin-top: 32px; }
@media (min-width: 900px) { .versus { grid-template-columns: repeat(3, 1fr); } }
.versus > div { background: var(--panel); border-radius: var(--radius); padding: 24px; min-width: 0; }
.versus h3 { margin: 4px 0 10px; font-size: 1.25rem; }
.versus p:last-child { color: var(--grey); margin: 0; font-size: 0.95rem; }
.versus .mono { margin: 0; }
.versus .hal { background: var(--field); color: #fff; transition: background 0.6s; }
.versus .hal .mono, .versus .hal p:last-child { color: rgba(255,255,255,0.9); }
.note a { color: inherit; }
.close { font-size: clamp(1.4rem, 2.6vw, 2rem); font-weight: 600; letter-spacing: -0.03em; line-height: 1.2; margin: 56px 0 0; max-width: 26ch; }

/* Inside HAL: light headset view, tinted with the learner color */
.viewport {
  --r: 600px;
  position: relative; height: 560px; overflow: hidden; outline: none; margin-top: 12px;
  border-radius: 24px; border: 1px solid var(--hair);
  background: radial-gradient(ellipse 70% 60% at 50% 42%, #ffffff, var(--field-soft) 80%);
  perspective: var(--r); perspective-origin: 50% 45%;
  cursor: grab; touch-action: pan-y; user-select: none; transition: background 0.6s;
}
.viewport.grabbing { cursor: grabbing; }
.viewport:focus-visible { outline: 2px solid var(--ink); outline-offset: 3px; }
.vp-horizon { position: absolute; left: 0; right: 0; top: 64%; height: 1px; background: var(--field-tint); }
.ring { position: absolute; left: 50%; top: 45%; width: 0; height: 0; transform-style: preserve-3d; }
.station {
  position: absolute; width: clamp(240px, 34vw, 380px); left: calc(clamp(240px, 34vw, 380px) / -2); top: -170px;
  display: flex; flex-direction: column; align-items: center; text-align: center;
  backface-visibility: hidden; transition: opacity 0.2s;
}
.station-tag { text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 14px; }
.station-card { margin: 18px 0 0; font-size: 0.88rem; color: var(--grey); padding: 10px 14px; border-radius: 12px; background: #fff; box-shadow: 0 1px 2px rgba(14,15,18,0.06), 0 8px 24px -12px rgba(14,15,18,0.18); max-width: 300px; }
.station-card b { display: block; color: var(--ink); font-weight: 600; margin-bottom: 2px; }

.st-orbit, .st-bars, .st-cell, .st-word, .st-cube, .st-molecule { position: relative; width: 240px; height: 170px; }
.st-orbit .planet { position: absolute; left: 50%; top: 50%; width: 72px; height: 72px; transform: translate(-50%, -50%); border-radius: 50%; background: var(--field); transition: background 0.6s; }
.st-orbit .orbit { position: absolute; left: 50%; top: 50%; width: 228px; height: 86px; transform: translate(-50%, -50%) rotate(-12deg); border: 1px solid var(--field-tint); border-radius: 50%; animation: spin 10s linear infinite; }
.moon { position: absolute; top: -7px; left: 50%; width: 14px; height: 14px; border-radius: 50%; background: var(--ink); }
@keyframes spin { to { transform: translate(-50%, -50%) rotate(348deg); } }
.st-bars { display: flex; align-items: flex-end; gap: 8px; padding: 0 12px; border-bottom: 1px solid var(--ink); }
.st-bars i { flex: 1; height: var(--h); background: var(--field); border-radius: 3px 3px 0 0; transition: background 0.6s; }
.st-cell { border-radius: 50%; width: 200px; height: 170px; border: 1.5px solid var(--field); background: var(--field-soft); }
.st-cell .nucleus { position: absolute; left: 50%; top: 50%; width: 54px; height: 54px; transform: translate(-50%, -50%); border-radius: 50%; background: var(--field); }
.st-cell i { position: absolute; width: 14px; height: 9px; border-radius: 50%; border: 1px solid var(--ink); }
.st-cell i:nth-child(2) { left: 22%; top: 26%; } .st-cell i:nth-child(3) { right: 20%; top: 30%; } .st-cell i:nth-child(4) { left: 28%; bottom: 22%; } .st-cell i:nth-child(5) { right: 26%; bottom: 20%; } .st-cell i:nth-child(6) { left: 14%; top: 54%; }
.st-word { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 10px; }
.st-word .word { font-size: 3rem; font-weight: 700; letter-spacing: -0.04em; }
.st-cube { display: grid; place-items: center; perspective: 600px; }
.cube { position: relative; width: 90px; height: 90px; transform-style: preserve-3d; animation: tumble 12s linear infinite; }
.cube i { position: absolute; inset: 0; border: 1.5px solid var(--field); background: rgba(255,255,255,0.55); }
.cube i:nth-child(1) { transform: translateZ(45px); } .cube i:nth-child(2) { transform: rotateY(180deg) translateZ(45px); }
.cube i:nth-child(3) { transform: rotateY(90deg) translateZ(45px); } .cube i:nth-child(4) { transform: rotateY(-90deg) translateZ(45px); }
.cube i:nth-child(5) { transform: rotateX(90deg) translateZ(45px); } .cube i:nth-child(6) { transform: rotateX(-90deg) translateZ(45px); }
@keyframes tumble { from { transform: rotateX(-20deg) rotateY(0); } to { transform: rotateX(-20deg) rotateY(360deg); } }
.atom { position: absolute; display: grid; place-items: center; border-radius: 50%; font-family: var(--mono); font-weight: 500; z-index: 1; }
.atom.o { width: 70px; height: 70px; left: 85px; top: 30px; background: var(--field); color: #fff; }
.atom.h { width: 42px; height: 42px; background: #fff; color: var(--ink); font-size: 0.8rem; box-shadow: inset 0 0 0 1.5px var(--ink); }
.h1 { left: 26px; top: 104px; } .h2 { right: 26px; top: 104px; }
.bond { position: absolute; left: 120px; top: 65px; height: 2px; width: 94px; background: var(--ink); transform-origin: 0 50%; }
.b1 { transform: rotate(141deg); } .b2 { transform: rotate(39deg); }

.hud { position: absolute; inset: 0; pointer-events: none; }
.hud-top { position: absolute; top: 16px; left: 50%; transform: translateX(-50%); display: flex; gap: 12px; align-items: center; text-transform: uppercase; letter-spacing: 0.08em; padding: 6px 14px; border-radius: 999px; background: #fff; box-shadow: 0 1px 2px rgba(14,15,18,0.08); white-space: nowrap; }
.hud-top b { color: var(--ink); font-weight: 500; }
.hud-teacher { position: absolute; left: 18px; bottom: 18px; max-width: 340px; padding: 14px 16px; border-radius: 14px; background: #fff; box-shadow: 0 1px 2px rgba(14,15,18,0.08), 0 12px 32px -16px rgba(14,15,18,0.25); font-size: 0.9rem; }
.hud-teacher p { margin: 0; }
.hud-label { display: flex; align-items: center; gap: 6px; margin-bottom: 6px !important; }
.hud-label::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--field); }
.hud-hint { position: absolute; right: 20px; bottom: 26px; transition: opacity 0.4s; }
.hud-hint.used { opacity: 0; }
@media (max-width: 640px) {
  .viewport { height: 500px; border-radius: 18px; }
  .hud-teacher { left: 10px; right: 10px; bottom: 10px; max-width: none; }
  .hud-hint { top: 52px; bottom: auto; right: 50%; transform: translateX(50%); }
}

.features { display: grid; gap: 32px; margin-top: 56px; }
@media (min-width: 900px) { .features { grid-template-columns: repeat(3, 1fr); } }
.features article { border-top: 1px solid var(--ink); padding-top: 16px; }
.features h3 { margin: 6px 0 8px; font-size: 1.25rem; }
.features article p:last-child { color: var(--grey); margin: 0; }

/* Two loops */
.loops { display: grid; gap: 16px; margin-top: 8px; }
@media (min-width: 860px) { .loops { grid-template-columns: 1fr 1fr; } }
.loop { background: var(--panel); border-radius: var(--radius); padding: 24px; min-width: 0; }
.loop .mono { margin: 0; }
.loop h3 { margin: 4px 0 16px; }
.loop p:last-child { color: var(--grey); margin: 16px 0 0; font-size: 0.95rem; }
.chain { display: flex; flex-wrap: wrap; gap: 8px 6px; align-items: center; font-size: 0.92rem; }
.chain span { background: #fff; border-radius: 999px; padding: 6px 12px; box-shadow: inset 0 0 0 1px var(--hair); }
.chain em { font-style: normal; color: var(--grey); }
.chain span.last { background: var(--field); color: #fff; box-shadow: none; transition: background 0.6s; }

/* Signal */
.two { display: grid; gap: 40px; }
@media (min-width: 940px) { .two { grid-template-columns: 1fr 1fr; align-items: center; gap: 64px; } }
.profile { border-radius: var(--radius); padding: 24px; background: var(--field-soft); transition: background 0.6s; }
.profile-head { display: flex; justify-content: space-between; gap: 10px; margin-bottom: 6px; flex-wrap: wrap; }
.profile .r { display: grid; grid-template-columns: 1fr auto; gap: 8px 12px; padding: 12px 0; border-top: 1px solid rgba(14,15,18,0.08); }
.profile .r .mono { color: var(--ink); }
.profile .r i { grid-column: 1 / -1; height: 6px; border-radius: 3px; background: rgba(14,15,18,0.08); position: relative; overflow: hidden; }
.profile .r i::before { content: ""; position: absolute; inset: 0 auto 0 0; width: var(--v); background: var(--field); border-radius: 3px; transition: background 0.6s; }
.profile .foot { margin: 14px 0 0; }

/* Roadmap */
.roadmap { list-style: none; margin: 8px 0 0; padding: 0; display: grid; gap: 16px; }
@media (min-width: 900px) { .roadmap { grid-template-columns: repeat(4, 1fr); } }
.roadmap li { background: var(--panel); border-radius: var(--radius); padding: 22px; }
.roadmap li.now { background: var(--field); color: #fff; transition: background 0.6s; }
.roadmap li.now .mono, .roadmap li.now p { color: rgba(255,255,255,0.88); }
.roadmap h3 { margin: 10px 0 8px; }
.roadmap p { color: var(--grey); margin: 0; font-size: 0.95rem; }

/* Team */
.team { display: grid; gap: 16px; }
@media (min-width: 800px) { .team { grid-template-columns: 1fr 1fr; } }
.person { display: flex; gap: 20px; align-items: flex-start; border-top: 1px solid var(--ink); padding-top: 18px; }
.person .mono { margin: 0 0 6px; }
.person h3 { font-size: 1.35rem; margin-bottom: 8px; }
.person p:last-child { color: var(--grey); margin: 0; font-size: 0.95rem; }
.photo { width: 96px; height: 96px; flex: none; border-radius: 14px; object-fit: cover; }
.photo-empty { display: grid; place-items: center; background: var(--panel); font-family: var(--mono); color: var(--grey); font-size: 1.2rem; }
@media (max-width: 480px) { .person { flex-direction: column; } }

/* Contact + footer */
.contact h2 { font-size: clamp(2.4rem, 5vw, 4rem); max-width: 16ch; }
.footer { border-top: 1px solid var(--hair); padding: 28px 0; }
.footer-inner { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 16px 24px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 8px 22px; font-size: 0.9rem; }
.footer-links a { text-decoration: none; color: var(--grey); }
.footer-links a:hover { color: var(--ink); }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
}