:root {
  --ink: #09090b;
  --panel: #111115;
  --panel-2: #17161a;
  --line: rgba(209, 196, 171, .16);
  --line-strong: rgba(209, 196, 171, .34);
  --silver: #d1c4ab;
  --silver-bright: #eee7dc;
  --plum: #4a334f;
  --plum-light: #725579;
  --text: #f3f0ea;
  --muted: #a5a0a1;
  --success: #98b79c;
  --error: #c98e91;
  --serif: "Cinzel", Georgia, serif;
  --sans: "Montserrat", system-ui, sans-serif;
  --radius: 18px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; background: var(--ink); }
body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  overflow-x: hidden;
  color: var(--text);
  background:
    radial-gradient(circle at 73% 8%, rgba(74, 51, 79, .2), transparent 27rem),
    linear-gradient(180deg, #0c0b0e 0%, var(--ink) 42%, #0b0a0c 100%);
  font-family: var(--sans);
  line-height: 1.6;
}
button, a, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button:focus-visible, a:focus-visible, input:focus-visible {
  outline: 2px solid var(--silver);
  outline-offset: 4px;
}
a { color: inherit; text-decoration: none; }
[hidden] { display: none !important; }

.skip-link {
  position: fixed;
  z-index: 100;
  top: 12px;
  left: 12px;
  padding: 10px 14px;
  transform: translateY(-150%);
  border-radius: 8px;
  color: var(--ink);
  background: var(--silver-bright);
}
.skip-link:focus { transform: translateY(0); }

.ambient {
  position: fixed;
  z-index: -1;
  width: 32rem;
  height: 32rem;
  border-radius: 50%;
  filter: blur(90px);
  pointer-events: none;
  opacity: .1;
}
.ambient-one { top: 25%; right: -20rem; background: var(--plum-light); }
.ambient-two { bottom: -22rem; left: -12rem; background: var(--silver); }

.site-header {
  width: min(1180px, calc(100% - 48px));
  min-height: 88px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}
.brand { display: inline-flex; align-items: center; gap: 13px; }
.brand-mark {
  width: 43px;
  height: 43px;
  display: grid;
  place-items: center;
  border: 1px solid var(--silver);
  color: var(--silver);
  font-family: var(--serif);
  font-size: 23px;
}
.brand-mark.small { width: 36px; height: 36px; font-size: 18px; }
.brand-copy { display: flex; flex-direction: column; line-height: 1.1; }
.brand-copy strong, .footer-brand strong {
  color: var(--silver-bright);
  font-family: var(--serif);
  font-size: 16px;
  font-weight: 600;
  letter-spacing: .16em;
}
.brand-copy small {
  margin-top: 6px;
  color: var(--muted);
  font-size: 9px;
  letter-spacing: .2em;
  text-transform: uppercase;
}
.site-header nav { display: flex; align-items: center; gap: 30px; }
.site-header nav a {
  position: relative;
  color: var(--muted);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .14em;
  text-transform: uppercase;
  transition: color .2s ease;
}
.site-header nav a:hover, .site-header nav a.nav-current { color: var(--silver-bright); }
.site-header nav a.nav-current::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: -12px;
  left: 0;
  height: 1px;
  background: var(--silver);
}

main { width: min(1180px, calc(100% - 48px)); margin: 0 auto; }
.hero {
  position: relative;
  min-height: calc(100vh - 88px);
  padding: clamp(64px, 10vw, 128px) 0 64px;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(340px, .95fr);
  align-items: center;
  column-gap: clamp(30px, 8vw, 112px);
}
.hero-copy { position: relative; z-index: 2; }
.eyebrow {
  margin: 0 0 22px;
  color: var(--silver);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .2em;
  text-transform: uppercase;
}
.hero .eyebrow { display: flex; gap: 30px; }
.hero .eyebrow span + span { color: #696569; }
h1, h2, h3 { font-family: var(--serif); font-weight: 500; }
h1 {
  margin: 0;
  max-width: 720px;
  font-size: clamp(54px, 7.6vw, 112px);
  line-height: .94;
  letter-spacing: -.045em;
  text-transform: uppercase;
}
h1 em { color: var(--silver); font-style: normal; }
.hero-lede {
  max-width: 620px;
  margin: 34px 0 0;
  color: var(--muted);
  font-size: clamp(15px, 1.8vw, 18px);
  line-height: 1.8;
}
.hero-actions { margin-top: 40px; display: flex; align-items: center; gap: 24px; flex-wrap: wrap; }
.button {
  min-height: 50px;
  padding: 0 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  border: 1px solid transparent;
  border-radius: 999px;
  cursor: pointer;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
  transition: transform .2s ease, background .2s ease, border-color .2s ease;
}
.button:hover { transform: translateY(-2px); }
.button-primary { color: #121014; background: var(--silver-bright); }
.button-primary:hover { background: #fff; }
.button-quiet { color: var(--silver); background: transparent; border-color: var(--line-strong); }
.button-quiet:hover { border-color: var(--silver); }
.time-note { color: #777277; font-size: 10px; letter-spacing: .08em; text-transform: uppercase; }

.hero-object {
  position: relative;
  min-height: 570px;
  display: grid;
  place-items: center;
}
.orbit {
  position: absolute;
  border: 1px solid var(--line);
  border-radius: 50%;
}
.orbit-one { width: 470px; height: 470px; }
.orbit-two { width: 330px; height: 330px; border-style: dashed; opacity: .65; animation: rotate 50s linear infinite; }
.hero-vial { position: relative; z-index: 2; width: 185px; filter: drop-shadow(0 38px 38px rgba(0,0,0,.45)); }
.hero-cap {
  width: 128px;
  height: 50px;
  margin: 0 auto -2px;
  border: 1px solid #5d5b5e;
  border-radius: 9px 9px 5px 5px;
  background: repeating-linear-gradient(90deg, #343438 0 4px, #232327 4px 8px);
}
.hero-glass {
  height: 246px;
  padding: 48px 17px 20px;
  border: 1px solid rgba(218, 221, 224, .34);
  border-radius: 28px 28px 38px 38px;
  background: linear-gradient(100deg, rgba(255,255,255,.11), rgba(255,255,255,.025) 31%, rgba(255,255,255,.08) 85%, rgba(255,255,255,.025));
  box-shadow: inset 11px 0 24px rgba(255,255,255,.03), inset -11px 0 20px rgba(0,0,0,.15);
}
.hero-label {
  min-height: 134px;
  padding: 21px 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  border: 1px solid rgba(209,196,171,.46);
  color: #171419;
  background: linear-gradient(145deg, #d4c9b8, #b6aa98);
  text-align: center;
}
.hero-label small, .hero-label span { font-size: 7px; font-weight: 700; letter-spacing: .14em; }
.hero-label strong { margin: 8px 0 5px; font-family: var(--serif); font-size: 34px; font-weight: 600; }
.spec {
  position: absolute;
  padding-left: 38px;
  color: #716d70;
  font-size: 8px;
  letter-spacing: .12em;
}
.spec::before { content: ""; position: absolute; top: 50%; left: 0; width: 28px; height: 1px; background: var(--line-strong); }
.spec-a { top: 31%; right: 0; }
.spec-b { bottom: 27%; left: 0; }

.scope-note {
  grid-column: 1 / -1;
  align-self: end;
  max-width: 830px;
  margin-top: 60px;
  padding-top: 24px;
  display: flex;
  gap: 14px;
  border-top: 1px solid var(--line);
  color: #716d70;
  font-size: 10px;
  line-height: 1.7;
}
.scope-note p { margin: 0; }
.scope-note strong { color: var(--muted); font-weight: 600; }
.scope-icon {
  flex: 0 0 auto;
  width: 20px;
  height: 20px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  color: var(--silver);
  font-family: Georgia, serif;
}

.lab-experience { min-height: 100vh; padding: 68px 0 90px; }
.lab-topline { display: flex; align-items: flex-end; justify-content: space-between; }
.lab-topline .eyebrow { margin-bottom: 7px; }
.progress-name { margin: 0; font-family: var(--serif); font-size: 22px; letter-spacing: .04em; text-transform: uppercase; }
.progress-count { margin: 0; color: var(--muted); font-size: 12px; letter-spacing: .15em; }
.progress-track { height: 1px; margin: 22px 0 0; overflow: hidden; background: var(--line); }
.progress-track span { display: block; width: 16.667%; height: 100%; background: var(--silver); transition: width .45s ease; }
.lesson-nav {
  margin: 0 0 36px;
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  border-bottom: 1px solid var(--line);
}
.lesson-nav button {
  min-height: 66px;
  padding: 0;
  border: 0;
  color: #656166;
  background: transparent;
  cursor: pointer;
  font-size: 9px;
  font-weight: 600;
  letter-spacing: .11em;
  text-transform: uppercase;
}
.lesson-nav button span { margin-right: 7px; color: #4c494d; }
.lesson-nav button.is-active { color: var(--silver-bright); }
.lesson-nav button.is-active span { color: var(--silver); }
.lesson-nav button.is-complete::after { content: " ·"; color: var(--success); }

.lesson-stage {
  min-height: 590px;
  display: grid;
  grid-template-columns: minmax(340px, .9fr) minmax(0, 1.1fr);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: rgba(17, 17, 21, .8);
  box-shadow: 0 28px 90px rgba(0,0,0,.22);
}
.visual-panel {
  position: relative;
  min-height: 590px;
  padding: 45px;
  display: grid;
  place-items: center;
  overflow: hidden;
  border-right: 1px solid var(--line);
  background:
    linear-gradient(rgba(209,196,171,.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(209,196,171,.035) 1px, transparent 1px),
    radial-gradient(circle at center, rgba(74,51,79,.19), transparent 55%);
  background-size: 34px 34px, 34px 34px, auto;
}
.visual-panel::after {
  content: "NOCTIS / TRAINING ENVIRONMENT";
  position: absolute;
  right: 18px;
  bottom: 14px;
  color: #49464a;
  font-size: 7px;
  letter-spacing: .15em;
}
.lesson-copy { padding: clamp(38px, 6vw, 74px); align-self: center; }
.lesson-index { margin: 0 0 15px; color: var(--plum-light); font-size: 10px; font-weight: 700; letter-spacing: .18em; }
.lesson-copy h2 { margin: 0; font-size: clamp(32px, 4vw, 52px); line-height: 1.12; text-transform: uppercase; }
.lesson-copy > p { margin: 23px 0 0; color: var(--muted); font-size: 14px; line-height: 1.85; }
.key-idea {
  margin-top: 28px;
  padding: 19px 20px;
  border-left: 2px solid var(--plum-light);
  color: var(--silver-bright);
  background: rgba(74,51,79,.12);
  font-size: 12px;
  line-height: 1.7;
}
.why-button {
  margin-top: 25px;
  padding: 0 0 6px;
  border: 0;
  border-bottom: 1px solid var(--line-strong);
  color: var(--silver);
  background: transparent;
  cursor: pointer;
  font-size: 9px;
  font-weight: 700;
  letter-spacing: .15em;
  text-transform: uppercase;
}
.why-button:hover { border-color: var(--silver); }
.selector { margin-top: 26px; display: flex; gap: 8px; flex-wrap: wrap; }
.selector button {
  min-width: 70px;
  min-height: 42px;
  padding: 0 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  background: transparent;
  cursor: pointer;
  font-size: 10px;
}
.selector button.is-active { border-color: var(--silver); color: var(--ink); background: var(--silver); }

.training-vial { position: relative; width: 166px; filter: drop-shadow(0 30px 30px rgba(0,0,0,.42)); }
.training-cap {
  width: 118px;
  height: 42px;
  margin: 0 auto -2px;
  border: 1px solid #59585b;
  border-radius: 8px 8px 3px 3px;
  background: repeating-linear-gradient(90deg, #343438 0 4px, #232327 4px 8px);
}
.training-glass {
  position: relative;
  height: 230px;
  overflow: hidden;
  border: 1px solid rgba(218,221,224,.35);
  border-radius: 26px 26px 36px 36px;
  background: linear-gradient(100deg, rgba(255,255,255,.1), rgba(255,255,255,.02) 36%, rgba(255,255,255,.07) 82%, rgba(255,255,255,.02));
}
.training-liquid {
  position: absolute;
  right: 3px;
  bottom: 3px;
  left: 3px;
  height: var(--liquid, 8%);
  min-height: 8px;
  border-radius: 0 0 31px 31px;
  background: linear-gradient(180deg, rgba(114,85,121,.58), rgba(74,51,79,.85));
  transition: height .35s ease;
}
.training-liquid::before { content: ""; position: absolute; top: -3px; right: 0; left: 0; height: 5px; border-radius: 50%; background: rgba(160,126,166,.65); }
.particle-field { position: absolute; inset: 0; z-index: 2; pointer-events: none; }
.particle-field i {
  position: absolute;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--silver-bright);
  box-shadow: 0 0 9px rgba(238,231,220,.7);
  opacity: .75;
  transition: top .35s ease;
}
.vial-sticker {
  position: absolute;
  z-index: 3;
  top: 54px;
  right: 12px;
  left: 12px;
  min-height: 102px;
  padding: 17px 10px;
  display: flex;
  flex-direction: column;
  align-items: center;
  color: #171419;
  background: linear-gradient(145deg, rgba(220,211,196,.96), rgba(183,172,155,.96));
  text-align: center;
}
.vial-sticker small, .vial-sticker span { font-size: 7px; font-weight: 700; letter-spacing: .14em; }
.vial-sticker strong { margin: 5px 0 2px; font-family: var(--serif); font-size: 29px; }
.measurement-readout {
  position: absolute;
  top: 28px;
  left: 28px;
  display: flex;
  flex-direction: column;
}
.measurement-readout span { color: #666167; font-size: 8px; letter-spacing: .14em; }
.measurement-readout strong { margin-top: 4px; color: var(--silver); font-family: var(--serif); font-size: 22px; font-weight: 500; }

.range-wrap { margin-top: 28px; }
.range-labels { margin-bottom: 10px; display: flex; justify-content: space-between; color: #6f6a70; font-size: 8px; letter-spacing: .1em; }
input[type="range"] {
  width: 100%;
  height: 3px;
  appearance: none;
  border: 0;
  border-radius: 3px;
  background: linear-gradient(90deg, var(--plum-light), var(--line-strong));
}
input[type="range"]::-webkit-slider-thumb {
  width: 20px;
  height: 20px;
  appearance: none;
  border: 4px solid var(--ink);
  border-radius: 50%;
  background: var(--silver-bright);
  box-shadow: 0 0 0 1px var(--silver);
  cursor: grab;
}
input[type="range"]::-moz-range-thumb {
  width: 13px;
  height: 13px;
  border: 4px solid var(--ink);
  border-radius: 50%;
  background: var(--silver-bright);
  box-shadow: 0 0 0 1px var(--silver);
}
.equation {
  margin-top: 18px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--silver);
  background: #0c0c0f;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 11px;
  text-align: center;
}
.relationship-grid { margin-top: 22px; display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px; }
.relationship-grid div { padding: 13px; border: 1px solid var(--line); border-radius: 10px; }
.relationship-grid span { display: block; color: #6f6a70; font-size: 8px; letter-spacing: .12em; text-transform: uppercase; }
.relationship-grid strong { display: block; margin-top: 4px; color: var(--silver-bright); font-size: 13px; }

.compare-visual { width: min(390px, 100%); display: grid; grid-template-columns: 1fr auto 1fr; align-items: end; gap: 18px; }
.mini-vial { text-align: center; }
.mini-bottle { position: relative; width: 108px; height: 160px; margin: 0 auto 14px; overflow: hidden; border: 1px solid rgba(218,221,224,.3); border-radius: 18px 18px 26px 26px; background: rgba(255,255,255,.035); }
.mini-bottle .training-liquid { height: var(--mini-liquid); }
.mini-bottle b { position: absolute; z-index: 3; top: 45%; right: 0; left: 0; color: var(--silver-bright); font-family: var(--serif); font-size: 17px; font-weight: 500; }
.mini-vial span { color: #767177; font-size: 8px; letter-spacing: .12em; text-transform: uppercase; }
.compare-arrow { align-self: center; color: var(--plum-light); font-size: 20px; }

.syringe-wrap { width: min(440px, 100%); transform: rotate(-7deg); }
.syringe {
  position: relative;
  height: 102px;
  display: flex;
  align-items: center;
}
.syringe-needle { width: 78px; height: 1px; background: linear-gradient(90deg, transparent, #8d8b8e); }
.syringe-hub { width: 28px; height: 28px; border: 1px solid #77757a; border-radius: 5px 0 0 5px; background: #29282c; }
.syringe-barrel {
  position: relative;
  width: 250px;
  height: 64px;
  overflow: hidden;
  border: 1px solid rgba(218,221,224,.48);
  background:
    repeating-linear-gradient(90deg, transparent 0 9px, rgba(209,196,171,.42) 9px 10px),
    linear-gradient(180deg, rgba(255,255,255,.1), rgba(255,255,255,.025));
}
.syringe-fluid {
  position: absolute;
  top: 4px;
  right: 4px;
  bottom: 4px;
  width: var(--fill, 20%);
  background: linear-gradient(90deg, rgba(74,51,79,.72), rgba(114,85,121,.52));
  transition: width .18s ease;
}
.syringe-plunger {
  position: relative;
  width: 90px;
  height: 22px;
  border-top: 1px solid #77757a;
  border-bottom: 1px solid #77757a;
  background: #242328;
}
.syringe-plunger::after { content: ""; position: absolute; top: -18px; right: 0; width: 8px; height: 56px; border: 1px solid #77757a; background: #242328; }
.syringe-caption { margin-top: 20px; display: flex; justify-content: center; gap: 28px; text-align: center; }
.syringe-caption span { display: block; color: #6f6a70; font-size: 7px; letter-spacing: .12em; }
.syringe-caption strong { color: var(--silver-bright); font-family: var(--serif); font-size: 20px; font-weight: 500; }

.verify-stack { width: min(410px, 100%); display: grid; gap: 10px; }
.verify-step {
  padding: 18px;
  display: grid;
  grid-template-columns: 37px 1fr;
  gap: 13px;
  border: 1px solid var(--line);
  border-radius: 12px;
  color: var(--muted);
  background: rgba(9,9,11,.68);
  cursor: pointer;
  text-align: left;
  transition: border-color .2s ease, transform .2s ease;
}
.verify-step:hover { transform: translateX(4px); border-color: var(--line-strong); }
.verify-step.is-open { border-color: var(--plum-light); }
.verify-step b { color: var(--silver); font-family: var(--serif); font-size: 17px; font-weight: 500; }
.verify-step strong { display: block; color: var(--silver-bright); font-size: 11px; letter-spacing: .06em; text-transform: uppercase; }
.verify-step small { display: none; margin-top: 7px; color: var(--muted); line-height: 1.6; }
.verify-step.is-open small { display: block; }

.challenge-panel { grid-template-columns: minmax(0, 1fr); }
.challenge-panel .visual-panel { min-height: 190px; border-right: 0; border-bottom: 1px solid var(--line); }
.challenge-panel .lesson-copy { width: min(760px, 100%); margin: auto; padding-top: 42px; padding-bottom: 42px; }
.challenge-meta { width: 100%; max-width: 760px; display: flex; align-items: center; justify-content: space-between; }
.challenge-meta .eyebrow { margin: 0; }
.score { color: var(--silver); font-family: var(--serif); font-size: 18px; }
.challenge-question { margin-top: 20px !important; color: var(--silver-bright) !important; font-size: 17px !important; line-height: 1.65 !important; }
.answer-grid { margin-top: 25px; display: grid; gap: 9px; }
.answer {
  min-height: 52px;
  padding: 13px 17px;
  display: flex;
  align-items: center;
  gap: 13px;
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--muted);
  background: rgba(9,9,11,.5);
  cursor: pointer;
  text-align: left;
}
.answer:hover:not(:disabled) { border-color: var(--silver); color: var(--silver-bright); }
.answer:disabled { cursor: default; }
.answer b { width: 24px; height: 24px; display: grid; place-items: center; border: 1px solid var(--line-strong); border-radius: 50%; color: var(--silver); font-size: 9px; }
.answer.correct { border-color: rgba(152,183,156,.55); color: var(--success); background: rgba(152,183,156,.07); }
.answer.incorrect { border-color: rgba(201,142,145,.55); color: var(--error); background: rgba(201,142,145,.06); }
.feedback {
  margin-top: 15px;
  padding: 16px 18px;
  border-left: 2px solid var(--silver);
  color: var(--muted);
  background: rgba(255,255,255,.025);
  font-size: 12px;
  line-height: 1.7;
}
.feedback strong { color: var(--silver-bright); }
.next-challenge { margin-top: 18px; }

.lesson-controls { margin-top: 22px; display: flex; justify-content: space-between; }
.lesson-controls .button { min-width: 145px; }

.completion { min-height: 72vh; padding: 120px 0; display: flex; flex-direction: column; justify-content: center; align-items: center; text-align: center; }
.completion h2 { max-width: 850px; margin: 0; font-size: clamp(34px, 6vw, 72px); line-height: 1.15; text-transform: uppercase; }
.completion > p:not(.eyebrow) { color: var(--muted); }
.completion-actions { margin-top: 30px; display: flex; gap: 12px; flex-wrap: wrap; justify-content: center; }

footer {
  width: min(1180px, calc(100% - 48px));
  margin: 0 auto;
  padding: 45px 0 55px;
  display: grid;
  grid-template-columns: 1fr 1.5fr auto;
  gap: 45px;
  align-items: start;
  border-top: 1px solid var(--line);
  color: #6f6a70;
  font-size: 9px;
  line-height: 1.8;
}
.footer-brand { display: flex; align-items: center; gap: 13px; }
.footer-brand div { display: flex; flex-direction: column; }
.footer-brand span { margin-top: 4px; font-size: 8px; letter-spacing: .12em; text-transform: uppercase; }
footer p { margin: 0; }
.copyright { white-space: nowrap; }

.why-dialog {
  width: min(600px, calc(100% - 32px));
  padding: 44px;
  border: 1px solid var(--line-strong);
  border-radius: 16px;
  color: var(--text);
  background: #121116;
  box-shadow: 0 34px 110px rgba(0,0,0,.7);
}
.why-dialog::backdrop { background: rgba(4,4,6,.82); backdrop-filter: blur(7px); }
.why-dialog h2 { margin: 0 0 18px; font-size: 29px; line-height: 1.25; text-transform: uppercase; }
.why-dialog #whyBody { color: var(--muted); font-size: 13px; line-height: 1.8; }
.why-dialog #whyBody p { margin: 0 0 13px; }
.dialog-close { position: absolute; top: 14px; right: 17px; border: 0; color: var(--muted); background: none; cursor: pointer; font-size: 24px; }
.sr-only { position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

@keyframes rotate { to { transform: rotate(360deg); } }

@media (max-width: 880px) {
  .hero { grid-template-columns: 1fr; padding-top: 70px; }
  .hero-object { min-height: 480px; margin-top: 28px; }
  .scope-note { margin-top: 20px; }
  .lesson-stage { grid-template-columns: 1fr; }
  .visual-panel { min-height: 410px; border-right: 0; border-bottom: 1px solid var(--line); }
  .lesson-stage { min-height: auto; }
  footer { grid-template-columns: 1fr 1fr; }
  .copyright { grid-column: 1 / -1; }
}

@media (max-width: 640px) {
  .site-header, main, footer { width: min(100% - 30px, 1180px); }
  .site-header { min-height: 74px; }
  .site-header nav { gap: 15px; }
  .site-header nav a { font-size: 8px; }
  .site-header nav a:last-child { display: none; }
  .brand-copy { display: none; }
  .brand-mark { width: 38px; height: 38px; font-size: 20px; }
  .hero { min-height: auto; padding: 66px 0 45px; }
  .hero .eyebrow { flex-direction: column; gap: 4px; }
  h1 { font-size: clamp(45px, 15vw, 68px); }
  .hero-lede { margin-top: 25px; font-size: 14px; }
  .hero-actions { align-items: flex-start; flex-direction: column; gap: 14px; }
  .hero-object { min-height: 410px; transform: scale(.88); margin: -5px 0; }
  .orbit-one { width: 390px; height: 390px; }
  .orbit-two { width: 285px; height: 285px; }
  .spec-a { right: -28px; }
  .spec-b { left: -35px; }
  .scope-note { font-size: 9px; }
  .lab-experience { padding-top: 45px; }
  .lesson-nav { grid-template-columns: repeat(3, 1fr); }
  .lesson-nav button { min-height: 50px; }
  .lesson-stage { border-radius: 13px; }
  .visual-panel { min-height: 360px; padding: 26px; }
  .lesson-copy { padding: 34px 25px 40px; }
  .lesson-copy h2 { font-size: 31px; }
  .lesson-copy > p { font-size: 13px; }
  .lesson-controls .button { min-width: 0; padding: 0 16px; gap: 10px; }
  .compare-visual { gap: 8px; }
  .mini-bottle { width: 90px; height: 145px; }
  .syringe-wrap { transform: rotate(-7deg) scale(.79); }
  .syringe { margin-left: -52px; width: 470px; }
  .syringe-caption { width: 370px; margin-left: -8px; }
  .challenge-panel .visual-panel { min-height: 135px; }
  .challenge-panel .lesson-copy { padding: 30px 22px 34px; }
  .why-dialog { padding: 38px 25px 27px; }
  footer { grid-template-columns: 1fr; gap: 25px; }
  .copyright { grid-column: auto; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}