:root {
  color-scheme: dark;
  --bg: #081322;
  --panel: #0e1f30;
  --ink: #edf4f5;
  --muted: #a6b8c5;
  --line: #2b4255;
  --mint: #58e4c1;
  --rose: #f6a8ba;
  --serif: Georgia, 'Times New Roman', serif;
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-padding-top: 1.5rem; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.7 Inter, 'Segoe UI', system-ui, sans-serif;
}
h1, h2, h3, p, figure { margin: 0 0 1rem; }
h1, h2, h3 { font-weight: 460; line-height: 1.1; }
p { color: var(--muted); }
a { color: inherit; text-underline-offset: .23em; }
a:hover { color: var(--mint); }
a:focus-visible, button:focus-visible, input:focus-visible, summary:focus-visible {
  outline: 3px solid var(--mint);
  outline-offset: 4px;
}
button, input { font: inherit; }
button, summary { cursor: pointer; }
.skip { position: fixed; z-index: 4; top: 1rem; clip-path: inset(50%); left: 1rem; padding: .5rem 1rem; background: var(--mint); color: var(--bg); }
.skip:focus { clip-path: none; }
.site-header, .site-footer {
  max-width: 1320px;
  margin: auto;
  padding: 20px 40px;
  display: flex;
  align-items: center;
  gap: 34px;
}
.site-header { position: relative; z-index: 2; border-bottom: 1px solid var(--line); }
.site-footer { justify-content: space-between; border-top: 1px solid var(--line); color: var(--muted); font-size: .75rem; }
.wordmark { display: flex; align-items: center; gap: 12px; text-decoration: none; font-size: .61rem; letter-spacing: .17em; line-height: 1.55; }
.wordmark b { font-size: .72rem; font-weight: 650; }
.site-purpose { margin: 0 auto 0 0; font: italic 1rem var(--serif); }
.author { color: var(--muted); font-size: .75rem; text-decoration: none; }
.menu { margin-left: auto; }
.menu summary { list-style: none; min-height: 44px; display: flex; gap: 16px; align-items: center; font-size: .78rem; }
.menu summary::-webkit-details-marker { display: none; }
.menu summary span { color: var(--mint); font-size: 1.25rem; }
.menu nav {
  position: absolute;
  right: 40px;
  top: calc(100% - 5px);
  width: min(330px, calc(100vw - 40px));
  padding: 12px 20px;
  background: var(--panel);
  border: 1px solid var(--line);
  box-shadow: 0 20px 50px #0006;
}
.menu a { display: block; padding: .55rem 0; text-decoration: none; font-size: .86rem; }
.menu a span { color: var(--mint); display: inline-block; width: 30px; }
.menu [aria-current] { color: var(--mint); }
main { max-width: 1240px; margin: auto; padding: 0 28px; min-height: 70vh; }
.eyebrow {
  color: var(--mint);
  letter-spacing: .16em;
  font-size: .69rem;
  font-weight: 660;
  text-transform: uppercase;
}
.hero {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  align-items: center;
  gap: clamp(30px, 6vw, 94px);
  padding: clamp(48px, 7vw, 92px) 0;
}
.hero h1 { font-size: clamp(3.45rem, 6.6vw, 6rem); letter-spacing: -.055em; margin: .21em 0 .24em; }
.hero h1 em { color: var(--mint); font-family: var(--serif); font-weight: 400; }
.lede { max-width: 39ch; }
.primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 1.4rem;
  min-height: 46px;
  padding: .66rem 1rem;
  border-radius: 4px;
  border: 1px solid var(--mint);
  background: var(--mint);
  color: #062822;
  font-size: .8rem;
  font-weight: 720;
  text-decoration: none;
}
.primary:hover { background: #a4f3e1; color: #062822; }
.fine { margin: .9rem 0 0; font-size: .74rem; }
.hero-visual { margin: 0; max-width: 425px; width: 100%; justify-self: center; }
.legend { display: flex; justify-content: space-between; gap: 12px; padding-bottom: 16px; color: var(--muted); font-size: .64rem; letter-spacing: .12em; }
.legend i { display: inline-block; width: .55rem; height: .55rem; margin-right: .25rem; border: 1px solid currentColor; border-radius: 2px; }
.legend span:first-child { color: var(--mint); }
.legend span:first-child i { background: var(--mint); }
.legend span:last-child { color: var(--rose); }
.blueprint {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: clamp(8px, 1.35vw, 16px);
  padding: clamp(15px, 2vw, 28px);
  background-color: #0a1d2d;
  background-image: linear-gradient(#21405060 1px, transparent 1px), linear-gradient(90deg, #21405060 1px, transparent 1px);
  background-size: 18px 18px;
  border: 1px solid var(--line);
  border-top: 3px double #4f8290;
}
.blueprint span {
  display: grid;
  place-items: center;
  min-height: clamp(38px, 5vw, 67px);
  border: 1px solid #438b86;
  border-radius: 2px;
  background: #153b42;
  color: #8ff1db;
  font: 1.15rem var(--serif);
  box-shadow: inset 0 0 0 4px #0813224d;
}
.blueprint .unlit { border: 1px dashed #be7086; background: #322434; color: var(--rose); }
figcaption { display: flex; gap: .85rem; margin: 1.25rem 0 0; font: 1.23rem/1.5 var(--serif); color: #c8d6df; }
figcaption > span { color: var(--mint); font-size: 1.9rem; line-height: 1; }
figcaption small { display: block; margin-top: .55rem; font: .68rem/1.5 system-ui, sans-serif; color: var(--muted); }
.index { padding: 40px 0 0; border-top: 1px solid var(--line); }
.index-intro { max-width: 56ch; margin-bottom: 32px; }
.index-intro h2, .sources h2 { font-size: clamp(2rem, 4.5vw, 3.7rem); letter-spacing: -.04em; }
.index-row {
  display: grid;
  grid-template-columns: 90px minmax(0, 1fr) auto;
  align-items: center;
  gap: 20px;
  padding: 24px 0;
  border-top: 1px solid var(--line);
}
.index-number { color: var(--mint); font: 2rem var(--serif); }
.index-row h3 { margin: .2em 0; font-size: clamp(1.35rem, 3vw, 2rem); }
.index-row h3 a { text-decoration: none; }
.index-row h3 span, .direct { color: var(--mint); }
.index-row h3 span { font-size: .65em; }
.index-row p { margin: 0; }
.direct, .scene-source { font-size: .8rem; }
.sources { border-top: 1px solid var(--line); padding: 50px 0 65px; }
.sources p { max-width: 72ch; }
.sources ul { padding-left: 1.1em; }
.sources a { color: var(--mint); }
.breadcrumbs { display: flex; justify-content: space-between; gap: 1rem; padding: 25px 0 0; color: var(--muted); font-size: .78rem; }
.chapter-heading { padding: clamp(38px, 6vw, 76px) 0 34px; }
.chapter-heading h1 { font-size: clamp(2.9rem, 7vw, 5.85rem); letter-spacing: -.055em; }
.chapter-question { margin: 0; color: var(--mint); font: italic clamp(1.25rem, 3.2vw, 2.1rem)/1.3 var(--serif); }
.story-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.12fr);
  gap: 42px clamp(35px, 7vw, 102px);
  border-top: 1px solid var(--line);
  padding: 35px 0;
}
.scene h2, .challenge h2, .lab h2 { font-size: clamp(1.75rem, 3.4vw, 2.65rem); letter-spacing: -.035em; }
.scene p:not(.eyebrow) { max-width: 55ch; }
.scene .eyebrow:not(:first-child) { margin-top: 2.6rem; }
.scene-source a { color: var(--mint); }
.lab {
  grid-column: 2;
  grid-row: 1 / span 2;
  align-self: start;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: clamp(17px, 3vw, 32px);
}
@media (min-width: 861px) and (min-height: 950px) {
  .lab { position: sticky; top: 20px; }
}
.lab > p:not(.eyebrow) { font-size: .91rem; }
.presets { display: flex; flex-wrap: wrap; gap: 7px; margin: 1.1rem 0 1.25rem; }
.presets button {
  min-height: 44px;
  border: 1px solid #4d6575;
  border-radius: 4px;
  padding: .45rem .65rem;
  background: #0c1b2a;
  color: var(--ink);
  font-size: .76rem;
}
.presets button:hover, .presets [aria-pressed=true] { border-color: var(--mint); color: var(--mint); background: #16383b; }
.controls label { display: flex; align-items: baseline; justify-content: space-between; gap: .6rem; font-size: .83rem; }
.input-value { color: var(--mint); font-weight: 700; white-space: nowrap; }
input[type=range] { width: 100%; height: 32px; margin: 0 0 .55rem; accent-color: var(--mint); }
.metrics { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; margin: .75rem 0 1.1rem; }
.metric { padding: .65rem; border: 1px solid var(--line); display: flex; flex-direction: column; justify-content: space-between; font-size: .78rem; color: var(--muted); }
.metric output { font: 2rem/1.2 var(--serif); color: var(--mint); }
.bars { list-style: none; margin: 0; padding: 0; }
.bars li { display: grid; grid-template-columns: minmax(6.25rem, .9fr) 1fr 2.1rem; gap: .55rem; align-items: center; font-size: .76rem; margin: .48rem 0; }
.bars strong { text-align: right; }
progress { display: block; appearance: none; border: none; width: 100%; height: 8px; background: #263e51; color: var(--mint); border-radius: 4px; overflow: hidden; }
progress::-webkit-progress-bar { background: #263e51; }
progress::-webkit-progress-value { background: var(--mint); }
progress::-moz-progress-bar { background: var(--mint); }
.result-note { margin: 1rem 0; font-size: .8rem; }
.lab details { border-top: 1px solid var(--line); }
.lab summary { padding: .65rem 0 0; font-size: .81rem; }
.lab details p { margin: .7rem 0 0; font-size: .82rem; }
.challenge { grid-column: 1; border-top: 1px solid var(--line); padding-top: 24px; }
fieldset { border: 0; padding: 0; margin: 0 0 1rem; }
legend { padding: 0; margin-bottom: .7rem; }
fieldset label { display: flex; align-items: center; gap: .6rem; min-height: 44px; cursor: pointer; color: var(--muted); }
input[type=radio] { margin: 0; accent-color: var(--mint); width: 1.05rem; height: 1.05rem; flex: none; }
.quiz-feedback { margin: .65rem 0 0; min-height: 1.7em; }
.chapter-nav { display: flex; justify-content: space-between; gap: 1.2rem; padding: 25px 0 46px; border-top: 1px solid var(--line); font-size: .88rem; color: var(--mint); }
.chapter-nav a:last-child { text-align: right; }
@media (max-width: 860px) {
  .author { display: none; }
  .story-grid { display: flex; flex-direction: column; gap: 28px; }
  .lab { width: 100%; }
}
@media (max-width: 620px) {
  main { padding: 0 20px; }
  .site-header, .site-footer { padding: 15px 20px; gap: 15px; }
  .site-purpose { display: none; }
  .menu nav { right: 20px; }
  .hero { grid-template-columns: 1fr; gap: 36px; padding: 39px 0 48px; }
  .hero h1 { font-size: clamp(2.85rem, 11vw, 4.5rem); }
  .hero-visual { justify-self: start; }
  .index-row { grid-template-columns: 34px minmax(0, 1fr); gap: 8px 12px; }
  .index-number { align-self: start; font-size: 1.35rem; }
  .direct { grid-column: 2; }
  .site-footer { flex-wrap: wrap; }
}