@font-face {
  font-family: 'Anton';
  src: url('apollo-assets/Anton-Regular.ttf') format('truetype');
  font-style: normal;
  font-weight: 400;
  font-display: swap;
}
/* Optical navigation: aperture geometry, registration marks, and signal orange. */
:root {
  color-scheme: dark;
  --black: #09090d;
  --surface: #131318;
  --ink: #f4f4ee;
  --muted: #aaa5b7;
  --line: #38343f;
  --orange: #ff6333;
  --mono: 'SFMono-Regular', Consolas, 'Liberation Mono', monospace;
  --display: 'Anton', Impact, 'Arial Narrow', 'Helvetica Neue', sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 30px; }
body { margin: 0; background: var(--black); color: var(--ink); font: 16px/1.8 Arial, Helvetica, sans-serif; }
a { color: inherit; text-underline-offset: 5px; }
button, input { font: inherit; }
button { cursor: pointer; }
button, a, input { -webkit-tap-highlight-color: transparent; }
a:focus-visible, button:focus-visible, input:focus-visible, video:focus-visible { outline: 2px solid var(--orange); outline-offset: 6px; }
::selection { background: var(--orange); color: var(--black); }
.wrap { max-width: 1520px; padding-inline: 64px; margin-inline: auto; }
.muted { color: var(--muted); }
.skip { position: absolute; top: -120px; left: 20px; z-index: 20; padding: 15px; color: var(--black); background: var(--ink); }
.skip:focus { top: 20px; }
.masthead { height: 110px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.home { display: flex; align-items: center; gap: 12px; text-decoration: none; font: 10px var(--mono); letter-spacing: .6px; }
.home-mark { font: 34px/1 Arial, sans-serif; color: var(--orange); }
.mast-center, .source-link { font: 10px var(--mono); letter-spacing: 1px; }
.mast-center { color: var(--muted); }
.source-link { text-decoration: none; }
.source-link span { color: var(--orange); margin-left: 12px; }
.eyebrow { font: 9px/1.6 var(--mono); letter-spacing: 1.5px; text-transform: uppercase; }
p { margin: 0 0 20px; }
h1, h2, h3 { margin: 0; }
h2 { font: 400 clamp(42px, 4.4vw, 66px)/1.03 var(--display); letter-spacing: .2px; text-transform: uppercase; }
h2 em, h3 em { font-style: normal; color: var(--orange); }
.sighting-mark { display: inline-block; width: 13px; height: 13px; border: 1px solid var(--orange); border-radius: 50%; position: relative; vertical-align: middle; margin-right: 10px; }
.sighting-mark::before, .sighting-mark::after { content: ''; position: absolute; background: var(--orange); }
.sighting-mark::before { left: 5px; top: -4px; width: 1px; height: 19px; }
.sighting-mark::after { left: -4px; top: 5px; height: 1px; width: 19px; }
.hero { display: grid; grid-template-columns: .78fr 1.22fr; gap: 12px; align-items: center; padding-top: 16px; padding-bottom: 68px; }
.hero-copy { position: relative; z-index: 1; padding-top: 10px; }
.hero .eyebrow { color: var(--muted); font-size: 8px; letter-spacing: 1px; margin-bottom: 28px; }
h1 { font: 400 clamp(95px, 10.5vw, 160px)/.85 var(--display); letter-spacing: 1px; }
h1 > span { display: block; margin-top: 22px; padding-left: 5px; font: 400 clamp(42px, 4.6vw, 70px)/.96 var(--display); color: var(--orange); letter-spacing: .5px; }
.hero-deck { margin: 28px 0 14px 5px; font-size: 17px; line-height: 1.7; }
.hero-intro { max-width: 335px; margin-left: 5px; font-size: 13px; line-height: 1.8; color: var(--muted); }
.hero-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 25px; margin: 29px 0 30px 5px; }
.button { display: inline-flex; align-items: center; gap: 25px; font: 9px var(--mono); text-decoration: none; letter-spacing: .5px; }
.primary { color: var(--black); background: var(--orange); border: 1px solid var(--orange); padding: 18px 21px; border-radius: 2px; }
.primary:hover { background: var(--ink); border-color: var(--ink); }
.button > span { font-size: 18px; }
.text-link { font: 9px/1.8 var(--mono); text-decoration: none; border-bottom: 1px solid var(--line); padding-bottom: 4px; letter-spacing: .3px; }
.text-link:hover { border-color: var(--orange); color: var(--orange); }
.edition { font: 8px var(--mono); letter-spacing: 1px; color: #aaa5b7; margin: 0 0 0 5px; }
.edition > span { color: var(--orange); padding-inline: 13px; }
.hero-figure { min-width: 0; margin: 0; }
.optics-label { display: flex; align-items: center; justify-content: space-between; margin: 0 24px 12px; font: 8px var(--mono); letter-spacing: 1px; color: var(--muted); }
.hero-figure svg { display: block; width: 100%; }
.svg-label { font: 11px var(--mono); fill: #f4f4ee; letter-spacing: .6px; }
.svg-tiny { font: 8px var(--mono); fill: #aaa5b7; letter-spacing: .8px; }
.hero-figure figcaption { text-align: center; padding-top: 18px; font: 9px/1.6 var(--mono); letter-spacing: .4px; }
.hero-figure figcaption small { display: block; font-size: 7px; color: var(--muted); margin-top: 9px; letter-spacing: 1px; }
.trajectory-reveal { stroke-dasharray: 1500; stroke-dashoffset: 0; animation: trace 2.4s ease-out both; }
@keyframes trace { from { stroke-dashoffset: 1500; } to { stroke-dashoffset: 0; } }
.mission-strip { display: grid; grid-template-columns: repeat(3, 1fr) 1.4fr; gap: 20px; font: 8px var(--mono); letter-spacing: 1px; }
.mission-strip > span { border-top: 1px solid var(--line); padding: 22px 0; color: var(--muted); }
.mission-strip b { font-weight: normal; color: var(--ink); }
.mission-strip .strip-end { text-align: right; color: var(--orange); }
.strip-end > span { margin-left: 18px; }
.chapter-nav { display: grid; grid-template-columns: repeat(6, 1fr); padding-top: 16px; padding-bottom: 56px; gap: 15px; }
.chapter-nav a { display: flex; flex-direction: column; gap: 10px; font: 10px var(--mono); color: var(--muted); text-decoration: none; }
.chapter-nav a > span { display: flex; align-items: center; justify-content: center; width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 50%; color: var(--ink); font-size: 11px; transition: background .2s, color .2s; }
.chapter-nav a:hover { color: var(--ink); }
.chapter-nav a:hover > span { background: var(--orange); border-color: var(--orange); color: var(--black); }
.film-section { background: #efede8; color: var(--black); padding: 65px 0 60px; position: relative; }
.film-section::before { content: ''; position: absolute; left: 0; top: 0; width: 92px; height: 8px; background: var(--orange); }
.section-heading { display: flex; align-items: flex-end; justify-content: space-between; gap: 48px; margin-bottom: 35px; }
.section-heading > p { color: var(--muted); font-size: 14px; line-height: 1.8; max-width: 255px; margin: 0 0 3px; }
.inverse .eyebrow { color: #66616a; margin-bottom: 16px; }
.inverse h2 { font-size: clamp(48px, 6.5vw, 90px); line-height: .92; }
.inverse h2 em { color: var(--black); }
.inverse > p { color: #66616a; }
.film-layout { display: grid; grid-template-columns: minmax(0, 3.1fr) minmax(230px, 1fr); gap: 38px; align-items: center; }
.film-frame { position: relative; min-width: 0; border: 9px solid #212025; background: var(--black); border-radius: 8px; line-height: 0; }
.film-frame::before, .film-frame::after { content: '+'; position: absolute; width: 22px; height: 22px; border-radius: 50%; font: 16px/21px Arial, sans-serif; text-align: center; background: #39373f; color: #aaa5b7; z-index: 1; top: -16px; }
.film-frame::before { left: -16px; }
.film-frame::after { right: -16px; }
.film-frame video { display: block; width: 100%; aspect-ratio: 16/9; }
.film-frame video::cue { font: 14px Arial, sans-serif; }
.margin-code { font: 9px var(--mono); letter-spacing: 1px; color: var(--orange); }
.film-notes .margin-code { color: #aa3719; }
.film-notes h3 { font: 400 31px/1.05 var(--display); text-transform: uppercase; margin: 19px 0; }
.film-notes h3 em { color: #aa3719; }
.film-notes p { font-size: 13px; color: #625b64; line-height: 1.8; }
.film-notes .fine { font-size: 11px; }
.film-rule { height: 1px; background: #c8c4ca; margin: 20px 0; }
.film-notes .text-link { font-size: 9px; border-color: #a29ca6; }
.lesson { padding-top: 28px; }
.note-section { display: grid; grid-template-columns: 110px minmax(0, 1fr); gap: 50px; padding: 85px 0; border-bottom: 1px solid var(--line); }
.section-marker { padding-top: 3px; }
.section-marker > span { display: block; font: 400 105px/.9 var(--display); letter-spacing: -2px; color: transparent; -webkit-text-stroke: 1px #706a7b; }
.section-marker > p { font: 8px/1.8 var(--mono); letter-spacing: 1px; color: var(--muted); margin: 16px 0 0; max-width: 95px; }
.two-col { display: grid; grid-template-columns: 1.14fr 1fr; gap: 45px; align-items: center; }
.body-copy, .section-lede { font-size: 15px; line-height: 1.95; color: #b7b1bf; }
.body-copy p:last-child { margin-bottom: 0; }
.body-copy strong { color: var(--ink); font-weight: 600; }
.cite { font: 10px var(--mono); color: var(--orange); white-space: nowrap; }
.state-card { aspect-ratio: 1; max-width: 380px; width: 100%; margin-inline: auto; border: 1px solid #4e4859; border-radius: 50%; padding: 56px 28px 39px; background: radial-gradient(circle, #1b1822 0, #0d0c11 69%); position: relative; box-shadow: 0 0 0 10px var(--black), 0 0 0 11px #26212e; display: flex; flex-direction: column; justify-content: center; }
.state-card::before { content: ''; position: absolute; inset: -5px; border: 1px dashed #4a414f; border-radius: 50%; pointer-events: none; }
.card-head { display: flex; justify-content: space-between; align-items: center; gap: 15px; font: 8px var(--mono); color: var(--muted); letter-spacing: .3px; }
.state-card .card-head { justify-content: center; flex-wrap: wrap; gap: 5px; font-size: 7px; }
.state-card .card-head span:first-child { color: var(--orange); }
.state-equation { display: flex; align-items: center; justify-content: center; gap: 15px; margin: 20px 0; }
.vector { font: 400 64px/.85 var(--display); text-align: center; }
.vector > span { font: 9px/1.5 var(--mono); color: var(--muted); display: block; margin-top: 12px; }
.plus { font: 20px var(--mono); color: var(--orange); }
.state-card > p { text-align: center; font-size: 11px; line-height: 1.7; color: var(--muted); margin: 0 0 18px; }
.state-foot { text-align: center; font: 7px/1.7 var(--mono); color: var(--muted); letter-spacing: .2px; }
.signal { display: inline-block; width: 5px; height: 5px; background: var(--orange); border-radius: 50%; margin-right: 7px; vertical-align: middle; }
.section-lede { max-width: 820px; margin: 0 0 30px; }
.lab { border: 1px solid #696270; border-radius: 18px; background: #121016; overflow: hidden; }
.lab-toolbar { display: flex; justify-content: space-between; align-items: center; gap: 20px; font: 8px var(--mono); letter-spacing: 1px; padding: 21px 25px; border-bottom: 1px solid var(--line); }
.lab-toolbar > span:last-child { color: var(--muted); }
.lab-grid { display: grid; grid-template-columns: minmax(0, 1fr) 270px; }
.lab-plot { min-width: 0; display: flex; flex-direction: column; justify-content: center; padding: 18px 15px; background: radial-gradient(ellipse at center, #1b1520 0, #0b0a0f 67%); }
.lab-plot svg { display: block; width: 100%; overflow: hidden; }
.lab-plot .orbit-mobile-only { display: none; }
.plot-legend { display: flex; flex-wrap: wrap; gap: 15px; padding: 12px 7px 0; font: 7px/1.8 var(--mono); color: var(--muted); }
.legend-line { display: inline-block; width: 13px; border-top: 1px solid var(--orange); vertical-align: middle; margin-right: 6px; }
.legend-line.lunar { border-top: 1px dashed var(--muted); }
.plot-scale { opacity: .75; }
.lab-controls { background: #e7e4df; color: var(--black); border-left: 1px solid #57515d; padding: 28px 25px; }
.lab-controls label { display: flex; align-items: center; justify-content: space-between; font: 9px var(--mono); letter-spacing: .5px; }
.lab-controls label > span { font: 20px var(--mono); }
#burn-value { display: block; font: 400 53px/1.2 var(--display); letter-spacing: 1px; margin: 15px 0; }
#burn-value small { font: 11px var(--mono); color: #625967; letter-spacing: 0; }
input[type=range] { display: block; appearance: none; -webkit-appearance: none; width: 100%; height: 3px; border: none; margin: 25px 0 18px; cursor: pointer; background: #77707d; touch-action: pan-y; }
input[type=range]::-webkit-slider-thumb { appearance: none; -webkit-appearance: none; width: 24px; height: 24px; border-radius: 50%; background: var(--orange); border: 5px solid #151319; box-shadow: 0 0 0 1px #66606b; cursor: ew-resize; }
input[type=range]::-moz-range-thumb { width: 14px; height: 14px; border-radius: 50%; background: var(--orange); border: 5px solid #151319; box-shadow: 0 0 0 1px #66606b; cursor: ew-resize; }
.range-ends { display: flex; justify-content: space-between; font: 8px var(--mono); color: #6b626e; }
#burn-help { font-size: 11px; line-height: 1.7; color: #625967; margin: 20px 0; }
.lab-button { display: flex; align-items: center; justify-content: space-between; gap: 12px; width: 100%; font: 9px/1.7 var(--mono); border: 1px solid #605666; padding: 11px 13px; background: transparent; color: #241d28; border-radius: 2px; }
.lab-button:hover { background: #d4ced8; }
.readouts { display: grid; gap: 19px; margin-top: 28px; }
.readouts > div { display: flex; flex-direction: column; }
.readouts span { font: 7px/1.7 var(--mono); letter-spacing: .7px; color: #625967; }
.readouts output { font: 400 28px/1.3 var(--display); margin-top: 5px; letter-spacing: .4px; }
.readouts small { font: 8px var(--mono); color: #625967; margin-top: 4px; }
.lab-bottom { border-top: 1px solid var(--line); padding: 18px 25px; display: flex; justify-content: space-between; align-items: center; gap: 20px; }
.lab-bottom p { font: 10px/1.8 var(--mono); margin: 0; max-width: 620px; color: #c6bfce; }
.reset-button { color: var(--orange); background: none; border: 0; padding: 8px 0 8px 8px; font: 9px var(--mono); white-space: nowrap; }
.equation-row { display: grid; grid-template-columns: 1fr 1.2fr; gap: 35px; align-items: center; padding: 35px 0 17px; }
.equation { display: flex; flex-direction: column; gap: 18px; }
.equation-label { font: 8px var(--mono); color: var(--orange); letter-spacing: 1px; }
.equation > span:last-child { display: flex; align-items: center; gap: 8px; font: 32px var(--mono); white-space: nowrap; }
.fraction { display: inline-flex; flex-direction: column; min-width: 23px; text-align: center; font-size: 22px; line-height: 1.1; }
.fraction span:first-child { border-bottom: 1px solid; padding: 0 5px 3px; }
.fraction span:last-child { padding-top: 3px; }
.paren { font-size: 52px; line-height: 1; }
.equation-row > p { font-size: 12px; color: var(--muted); line-height: 1.9; margin: 0; }
.model-note { font-size: 11px; color: var(--muted); line-height: 1.9; margin: 22px 0 0; border-left: 2px solid #534655; padding-left: 17px; }
.model-note strong { color: #d9d3df; }
.moon-clock { padding: 28px 30px; background: #151219; border-radius: 50% 50% 12px 12px; border: 1px solid #534957; }
.moon-clock .card-head { justify-content: center; font-size: 7px; padding-top: 6px; }
.moon-clock svg { display: block; width: 100%; overflow: visible; }
.clock-label { fill: #bab2c6; font: 8px var(--mono); letter-spacing: .2px; }
.clock-label.body-label { fill: #16121c; }
.clock-degrees { fill: var(--orange); font: 400 30px var(--display); }
.moon-clock label { display: flex; justify-content: space-between; font: 9px var(--mono); letter-spacing: .5px; color: var(--muted); }
.moon-clock output { color: var(--orange); }
.moon-clock > p { color: var(--muted); font-size: 10px; line-height: 1.8; margin: 20px 0 0; }
.wide { max-width: 850px; }
.iteration { display: flex; align-items: stretch; gap: 20px; margin-top: 35px; }
.iteration > div { flex: 1; min-width: 0; border-top: 3px solid var(--orange); padding: 25px 0; }
.iteration > div > span { color: var(--muted); font: 8px var(--mono); letter-spacing: 1px; }
.iteration h3 { font: 400 29px/1.1 var(--display); text-transform: uppercase; margin: 17px 0 14px; }
.iteration p { font-size: 13px; line-height: 1.8; color: var(--muted); margin: 0; }
.iteration-arrow { font-size: 22px; align-self: center; color: var(--orange); }
.pullquote { padding: 33px 0 10px; position: relative; }
.pullquote > span { display: none; }
.pullquote p { border-left: 4px solid var(--orange); padding-left: 23px; font-size: 23px; line-height: 1.55; letter-spacing: -.3px; margin-bottom: 18px; }
.pullquote small { display: block; padding-left: 27px; font: 8px var(--mono); letter-spacing: 1px; color: var(--muted); }
.return-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 36px; }
.return-card { padding: 23px 0 0; border-top: 1px solid var(--line); }
.card-index { font: 9px var(--mono); color: var(--orange); letter-spacing: 1px; }
.return-card svg { display: block; width: 100%; margin: 15px 0 26px; border-radius: 90px; background: #19151f; }
.return-card h3 { font: 400 39px/1 var(--display); text-transform: uppercase; margin: 0 0 20px; }
.return-card p { font-size: 14px; color: var(--muted); line-height: 1.9; margin: 0; }
.entry-card { border-radius: 50%; aspect-ratio: 1; max-width: 370px; width: 100%; background: var(--orange); color: var(--black); padding: 54px 42px 40px; text-align: center; margin-inline: auto; display: flex; flex-direction: column; justify-content: center; }
.entry-card .margin-code { color: #491a12; font-size: 8px; letter-spacing: .5px; }
.entry-number { font: 400 104px/.9 var(--display); letter-spacing: -2px; margin: 16px 0 10px; }
.entry-number > span { color: #f4f4ee; }
.entry-card > p { font-size: 11px; line-height: 1.6; margin: 4px 0 15px; }
.entry-line { display: flex; align-items: center; justify-content: center; gap: 16px; padding-top: 12px; border-top: 1px solid #38160d55; font: 14px var(--mono); }
.entry-line > span:last-child { font-size: 7px; }
.entry-card > small { font-size: 8px; line-height: 1.6; margin-top: 10px; }
.knowledge-check { margin-top: 45px; padding: 28px 0 0; border-top: 1px solid var(--line); }
.knowledge-check .eyebrow { color: var(--orange); font-size: 8px; }
.knowledge-check h3 { font: 400 32px/1.15 var(--display); text-transform: uppercase; margin: 0 0 25px; }
.answer-buttons { display: flex; flex-wrap: wrap; gap: 14px; }
.answer-buttons button { font: 10px/1.5 var(--mono); border: 1px solid #625969; color: var(--ink); background: transparent; border-radius: 30px; padding: 15px 21px; }
.answer-buttons button:hover { border-color: var(--orange); }
.answer-buttons button[aria-pressed=true] { color: var(--black); background: var(--orange); border-color: var(--orange); }
#answer-feedback { margin: 20px 0 0; max-width: 730px; font-size: 13px; color: var(--muted); line-height: 1.8; }
.last-note { border: none; }
.sources-section { background: #1a171e; padding: 65px 0; border-top: 1px solid #554659; }
.sources-layout { display: grid; grid-template-columns: 1fr 1.5fr; gap: 100px; }
.sources-layout h2 { margin-bottom: 25px; }
.sources-layout .eyebrow { color: var(--muted); }
.sources-layout > div > p:not(.eyebrow) { color: var(--muted); max-width: 330px; font-size: 13px; line-height: 1.9; }
.sources-list { list-style: none; margin: 0; padding: 0 0 0 25px; counter-reset: sources; }
.sources-list li { padding: 0 0 20px 22px; margin-bottom: 20px; border-bottom: 1px solid #433748; position: relative; }
.sources-list li::before { counter-increment: sources; content: '0' counter(sources); position: absolute; top: 4px; left: -25px; font: 10px var(--mono); color: var(--orange); }
.sources-list li:last-child { border: 0; padding-bottom: 0; margin-bottom: 0; }
.sources-list a { display: flex; justify-content: space-between; gap: 20px; font-size: 14px; line-height: 1.5; text-decoration: none; }
.sources-list a:hover { color: var(--orange); }
.sources-list a > span { color: var(--orange); }
.sources-list p { font-size: 11px; line-height: 1.9; color: var(--muted); margin: 9px 0 0; }
.footer { display: flex; align-items: center; justify-content: space-between; gap: 20px; min-height: 110px; }
.footer > span, .footer > a:last-child { color: var(--muted); font: 8px var(--mono); letter-spacing: .5px; text-decoration: none; }
@media (max-width: 1150px) {
  .wrap { padding-inline: 38px; }
  .hero { grid-template-columns: .85fr 1.15fr; }
  .hero .eyebrow { font-size: 7px; }
  .hero-deck { font-size: 15px; }
  .hero-intro { font-size: 12px; }
  .hero-actions { gap: 18px; }
  .primary { padding: 15px 16px; font-size: 8px; }
  .text-link { font-size: 8px; }
  .note-section { grid-template-columns: 75px minmax(0, 1fr); gap: 30px; }
  .section-marker > span { font-size: 80px; }
  .section-heading > p { max-width: 210px; font-size: 13px; }
  .two-col { gap: 35px; }
  .state-card { padding: 43px 20px 35px; }
  .state-equation { gap: 10px; }
  .vector { font-size: 53px; }
  .lab-grid { grid-template-columns: minmax(0, 1fr) 235px; }
  .lab-controls { padding: 23px 20px; }
  .film-layout { gap: 25px; grid-template-columns: minmax(0, 2.6fr) minmax(195px, 1fr); }
  .film-notes h3 { font-size: 26px; }
  .entry-card { padding: 43px 22px; }
  .entry-number { font-size: 85px; }
  .entry-card > small { font-size: 7px; }
  .mission-strip { font-size: 7px; letter-spacing: .3px; }
}
@media (max-width: 850px) {
  .mast-center { display: none; }
  .masthead { height: 85px; }
  .hero { gap: 0; padding-top: 25px; padding-bottom: 44px; }
  h1 { font-size: clamp(70px, 10.5vw, 88px); }
  h1 > span { font-size: 39px; margin-top: 17px; }
  .hero .eyebrow { max-width: 220px; font-size: 7px; line-height: 1.9; letter-spacing: .2px; }
  .hero-deck { margin-top: 24px; font-size: 14px; }
  .hero-intro { max-width: 240px; }
  .hero-figure figcaption { font-size: 7px; }
  .hero-figure figcaption small { font-size: 6px; letter-spacing: .4px; }
  .optics-label { margin-inline: 5px; font-size: 6px; letter-spacing: .3px; }
  .edition { font-size: 6px; }
  .mission-strip { grid-template-columns: repeat(3, 1fr); }
  .mission-strip .strip-end { display: none; }
  .chapter-nav { gap: 8px; padding-bottom: 40px; }
  .chapter-nav a { font-size: 8px; line-height: 1.6; }
  .chapter-nav a > span { width: 34px; height: 34px; }
  .film-layout { grid-template-columns: 1fr; gap: 30px; }
  .film-notes { display: grid; grid-template-columns: 1fr 1.2fr; gap: 12px 35px; }
  .film-notes .margin-code { grid-column: 1/-1; }
  .film-notes h3 { grid-row: 2/5; margin: 0; font-size: 31px; }
  .film-notes p { margin: 0; font-size: 12px; }
  .film-rule { display: none; }
  .film-notes .text-link { justify-self: start; }
  .note-section { grid-template-columns: 1fr; gap: 25px; padding: 55px 0; }
  .section-marker { display: flex; align-items: center; gap: 18px; }
  .section-marker > span { font-size: 64px; }
  .section-marker > p { margin: 0; max-width: none; }
  .section-heading { gap: 25px; }
  .body-copy { font-size: 14px; }
  .entry-card { min-height: 285px; }
  .sources-layout { gap: 45px; grid-template-columns: 1fr 1.3fr; }
  .footer > span { display: none; }
}
@media (max-width: 620px) {
  html { scroll-padding-top: 20px; }
  .wrap { padding-inline: 24px; }
  .masthead { height: 76px; }
  .home { font-size: 8px; gap: 8px; }
  .home-mark { font-size: 28px; }
  .source-link { font-size: 8px; letter-spacing: .3px; }
  .source-link span { margin-left: 4px; }
  .hero { display: flex; flex-direction: column; align-items: stretch; gap: 30px; padding-top: 24px; padding-bottom: 30px; }
  .hero-copy { padding-top: 0; }
  .hero .eyebrow { max-width: none; font-size: 7px; letter-spacing: .4px; margin-bottom: 24px; }
  h1 { font-size: clamp(88px, 26vw, 158px); line-height: .8; letter-spacing: 1px; }
  h1 > span { font-size: 37px; line-height: .93; margin-top: 21px; padding-left: 0; }
  h1 > span br { display: none; }
  .hero-deck { margin: 23px 0 12px; font-size: 16px; }
  .hero-intro { max-width: 360px; margin-left: 0; font-size: 13px; }
  .hero-actions { margin: 24px 0; gap: 20px; }
  .primary { font-size: 8px; padding: 16px 14px; gap: 16px; }
  .text-link { font-size: 8px; }
  .edition { margin-left: 0; font-size: 7px; letter-spacing: .8px; }
  .hero-figure { margin-inline: -13px; }
  .optics-label { margin-inline: 22px; font-size: 7px; }
  .hero-figure figcaption { font-size: 8px; padding-top: 14px; }
  .hero-figure figcaption small { font-size: 7px; }
  .mission-strip { gap: 14px; font-size: 7px; letter-spacing: .2px; }
  .mission-strip > span { padding: 15px 0; line-height: 1.7; }
  .mission-strip b { display: block; font-size: 9px; }
  .chapter-nav { grid-template-columns: repeat(3, 1fr); gap: 20px 12px; padding-top: 14px; padding-bottom: 35px; }
  .chapter-nav a { flex-direction: row; align-items: center; font-size: 8px; gap: 9px; }
  .chapter-nav a > span { flex: 0 0 28px; width: 28px; height: 28px; font-size: 9px; }
  .film-section { padding: 38px 0; }
  .section-heading { display: block; margin-bottom: 26px; }
  .section-heading > p { max-width: 100%; margin: 20px 0 0; font-size: 13px; }
  .inverse .eyebrow { font-size: 8px; }
  .inverse h2 { font-size: 54px; }
  .inverse > p { font-size: 12px; }
  .film-frame { border-width: 5px; border-radius: 4px; }
  .film-frame::before, .film-frame::after { width: 16px; height: 16px; top: -11px; line-height: 16px; font-size: 12px; }
  .film-frame::before { left: -11px; }
  .film-frame::after { right: -11px; }
  .film-frame video::cue { font-size: 10px; }
  .film-notes { display: block; }
  .film-notes h3 { font-size: 31px; margin: 17px 0; }
  .film-notes h3 br { display: none; }
  .film-notes p { margin-bottom: 17px; }
  .film-notes .fine { font-size: 11px; }
  .lesson { padding-top: 8px; }
  .note-section { padding: 43px 0; gap: 23px; }
  .section-marker > span { font-size: 57px; }
  .section-marker > p { font-size: 8px; letter-spacing: .6px; }
  .section-heading h2 { font-size: 47px; line-height: .99; }
  .two-col { grid-template-columns: 1fr; gap: 39px; }
  .body-copy, .section-lede { font-size: 14px; line-height: 1.9; }
  .state-card { max-width: 315px; padding: 43px 20px 35px; }
  .state-equation { gap: 15px; }
  .vector { font-size: 60px; }
  .state-card .card-head { font-size: 7px; }
  .lab { border-radius: 13px; }
  .lab-toolbar { font-size: 7px; gap: 10px; padding: 17px 13px; letter-spacing: .2px; }
  .lab-grid { grid-template-columns: 1fr; }
  .lab-plot { padding: 15px 7px 20px; }
  .lab-plot .orbit-label { font-size: 20px; }
  .lab-plot .orbit-desktop-only { display: none; }
  .lab-plot .orbit-mobile-only { display: inline; }
  .plot-legend { font-size: 9px; gap: 8px 12px; }
  .lab-controls { border-left: 0; padding: 25px; }
  #burn-value { font-size: 62px; }
  .readouts { grid-template-columns: 1fr 1fr; gap: 12px; }
  .readouts output { font-size: 27px; }
  .readouts span { font-size: 6px; letter-spacing: .5px; }
  .lab-bottom { gap: 10px; padding: 15px; align-items: flex-start; }
  .lab-bottom p { font-size: 8px; }
  .reset-button { font-size: 8px; padding-top: 3px; }
  .equation-row { grid-template-columns: 1fr; gap: 25px; padding-top: 30px; }
  .equation > span:last-child { font-size: 29px; }
  .equation-row > p { font-size: 12px; }
  .model-note { font-size: 10px; padding-left: 14px; }
  .moon-clock { padding: 32px 24px 25px; }
  .moon-clock svg { margin: 9px 0; }
  .iteration { display: block; margin-top: 26px; }
  .iteration > div { padding: 21px 0; }
  .iteration h3 { font-size: 31px; }
  .iteration-arrow { display: block; width: 20px; transform: rotate(90deg); margin: 4px auto 23px; }
  .pullquote { padding-top: 23px; }
  .pullquote p { font-size: 20px; }
  .pullquote p br { display: none; }
  .pullquote small { font-size: 7px; }
  .return-grid { grid-template-columns: 1fr; gap: 34px; }
  .return-card h3 { font-size: 36px; }
  .entry-card { max-width: 315px; min-height: 0; padding: 42px 29px; }
  .entry-number { font-size: 94px; }
  .entry-card > small { font-size: 7px; }
  .knowledge-check { margin-top: 36px; }
  .knowledge-check h3 { font-size: 29px; }
  .answer-buttons { flex-direction: column; gap: 11px; }
  .answer-buttons button { font-size: 9px; padding: 15px; text-align: left; }
  #answer-feedback { font-size: 12px; }
  .sources-section { padding: 40px 0; }
  .sources-layout { grid-template-columns: 1fr; gap: 37px; }
  .sources-layout h2 { font-size: 49px; }
  .sources-list li { padding-left: 11px; }
  .sources-list a { font-size: 13px; }
  .footer { min-height: 95px; gap: 15px; }
  .footer > a:last-child { font-size: 7px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}