/* Field guide edition: presentation over the preserved learning engine. */
:root { --radius: 3px; --radius-lg: 6px; --plate: #283e32; --plate-ink: #e0e5ce; --plate-accent: #d8b968; }
[hidden] { display: none !important; }
.wrap { width: min(100% - 6rem, 78rem); }
body { font-size: 1.18rem; }
a { transition: color .15s ease; }
.site-header { border-bottom: 1px solid var(--rule); }
.site-header .bar { min-height: 106px; }
.wordmark { display: flex; align-items: center; gap: .8rem; color: var(--text); font: 600 1.22rem/1.05 var(--sans); letter-spacing: -.055em; }
.brand-period { color: var(--accent); }
.brand-symbol { display: block; width: 52px; height: 52px; object-fit: contain; flex-shrink: 0; }
.site-header nav { gap: 2rem; font-size: .85rem; }
.site-header nav a { color: var(--text); }
.button { padding: .95rem 1.35rem; border-radius: var(--radius); font-size: .88rem; font-weight: 500; }
.button .lucide { margin-left: .7rem; }
.text-link { font-size: .88rem; font-weight: 500; }
.eyebrow { font: 500 .68rem/1.5 var(--sans); letter-spacing: .15em; text-transform: uppercase; color: var(--muted); }
.hero { grid-template-columns: 1.1fr 1fr; gap: 5rem; padding-block: 5.5rem 4rem; align-items: center; }
.hero h1 { font-size: clamp(4rem, 6.8vw, 6.7rem); line-height: .98; letter-spacing: -.055em; margin: 1.75rem 0; }
h1 em, h2 em { font-weight: 400; color: var(--accent); }
.hero .lead { font-size: 1.18rem; line-height: 1.65; max-width: 28rem; color: var(--muted); }
.availability-dot { display: inline-block; width: 6px; height: 6px; background: var(--accent); border-radius: 50%; margin-right: .5rem; vertical-align: middle; }
.hero .actions { margin-top: 2rem; gap: 1.4rem; }
.hero-footnote { margin-top: 1.5rem; font: .73rem/1.6 var(--sans); color: var(--muted); }
.orbital-plate { background: var(--plate); color: var(--plate-ink); padding: 1.5rem 1.5rem 1.6rem; transform: rotate(1.5deg); }
.plate-top { display: flex; justify-content: space-between; gap: 1rem; padding-bottom: .9rem; border-bottom: 1px solid currentColor; font: .52rem/1.5 var(--sans); letter-spacing: .12em; }
.orbital-plate svg { margin: .5rem 0 0; }
.hero-figure.orbital-plate figcaption { color: var(--plate-ink); max-width: none; border-top: 1px solid currentColor; padding-top: 1rem; font: .72rem/1.6 var(--sans); }
.orbital-plate figcaption span { font-family: var(--serif); font-size: 1.3rem; }
.orbital-plate figcaption p { opacity: .8; margin: .5rem 0; }
.orbital-plate figcaption a { color: inherit; font-size: .7rem; }
.availability { display: flex; justify-content: space-between; gap: 1rem; align-items: center; border-block: 1px solid var(--rule); padding-block: 1.2rem; font: .75rem/1.6 var(--sans); }
.availability strong { font-weight: 600; color: var(--accent); }
.availability p { margin: 0; }
.availability p:last-child { color: var(--muted); }
.availability span { padding-inline: .5rem; }
.section-heading { display: flex; align-items: center; justify-content: space-between; gap: 1rem; margin-bottom: 2.75rem; }
.section-heading p { margin: 0; }
.home-course { padding-block: 5rem; }
.course-intro { display: grid; grid-template-columns: 1.2fr 1fr; gap: 5rem; margin-bottom: 3rem; }
.course-intro h2 { font-size: clamp(2.8rem, 4.7vw, 4.5rem); line-height: 1.05; letter-spacing: -.035em; }
.course-intro > div { max-width: 29rem; }
.course-intro p { margin-top: 0; }
.note { font: .8rem/1.6 var(--sans); color: var(--muted); }
.lesson-preview { list-style: none; margin: 0; padding: 0; }
.lesson-preview li { border-top: 1px solid var(--rule); }
.lesson-preview li:last-child { border-bottom: 1px solid var(--rule); }
.lesson-preview a { display: grid; grid-template-columns: 4rem 1fr auto; align-items: center; gap: 1.5rem; padding: 1.6rem .5rem; text-decoration: none; color: var(--text); }
.lesson-preview a:hover { background: var(--surface); }
.preview-code { font: 500 .95rem var(--sans); color: var(--accent); }
.preview-label { display: block; font: .58rem var(--sans); letter-spacing: .13em; color: var(--muted); margin-bottom: .4rem; }
.lesson-preview h3 { margin: 0; font-size: 1.8rem; }
.preview-arrow { font-size: 1.75rem; color: var(--accent); }
.how { border-top: 1px solid var(--rule); padding-block: 4rem; }
.how h2 { color: var(--text); font-size: clamp(2.2rem, 4vw, 3.4rem); margin-bottom: 2.5rem; }
.steps { gap: 3rem; margin-bottom: 2rem; }
.steps li { padding-top: 1.3rem; }
.method-number { display: block; font: .7rem var(--sans); color: var(--accent); margin-bottom: 1.75rem; }
.steps h3 { font-size: 1.65rem; }
.steps h3::before { content: none; }
.steps p { font-size: 1.05rem; }
.about { display: grid; grid-template-columns: 1.2fr 1fr; gap: 1rem 5rem; border-top: 1px solid var(--rule); padding-block: 4rem 5rem; }
.about > .eyebrow { grid-column: 1 / -1; }
.about h2 { font-size: 3.8rem; color: var(--text); }
.about div p { margin-top: 0; }
.site-footer { padding-block: 2.5rem; background: var(--surface); }
.site-footer .wrap { display: flex; justify-content: space-between; align-items: flex-end; gap: 2rem; }
.site-footer p { font: .7rem/1.6 var(--sans); }
.site-footer .footer-brand { font: italic 2.5rem var(--serif); color: var(--text); margin-bottom: 1rem; }
.series-hero { padding-block: 4rem; }
.series-hero h1 { max-width: 60rem; font-size: clamp(3.5rem, 6vw, 6rem); letter-spacing: -.045em; }
.series-hero .lead { max-width: 39rem; font-size: 1.3rem; color: var(--muted); }
.key-numbers { border-block: 1px solid var(--rule); padding-block: 1.5rem; gap: 3rem; }
.key-numbers dd { font-family: var(--serif); font-size: 2.8rem; }
.key-numbers dt { font-size: .7rem; }
.how-short { font-size: .85rem; }
.roadmap-section { padding-top: 1rem; }
.filters { gap: 1.5rem; border-bottom: 1px solid var(--rule); padding-bottom: 1rem; }
.filters button { border: 0; background: transparent; border-radius: 0; color: var(--muted); padding-inline: 0; font-size: .8rem; }
.filters button[aria-pressed="true"] { color: var(--accent); background: transparent; text-decoration: underline; text-underline-offset: .8rem; }
.roadmap { grid-template-columns: 1fr; gap: 0; }
.chapter-card { position: relative; display: grid; grid-template-columns: 1fr 1fr; column-gap: 4rem; padding: 1.6rem 0; background: transparent; border: 0; border-bottom: 1px solid var(--rule); border-radius: 0; }
.chapter-card .card-head { grid-column: 1 / -1; margin-bottom: .5rem; }
.card-code { background: transparent; padding-left: 0; font-size: .85rem; }
.card-track, .card-status { font-size: .65rem; }
.chapter-card h3 { grid-column: 1; font-size: 1.8rem; margin-bottom: .5rem; }
.chapter-card h3 a { color: var(--text); text-decoration: none; }
.chapter-card h3 a:hover { color: var(--accent); text-decoration: underline; }
.chapter-card .card-goal { grid-column: 2; grid-row: 2 / 4; margin: 0; align-self: center; font-size: 1rem; }
.chapter-card .chips { grid-column: 1; font-size: .65rem; }
.chapter-card[data-status="planned"] { opacity: .68; }
.chapter-card[data-status="planned"] h3 { font-size: 1.5rem; }
.player .stepper-top { padding: 1rem 2rem 0; border-bottom: 1px solid var(--rule); }
.player .player-bar { width: min(100%, 76rem); min-height: 3rem; gap: 1rem; }
.player-identity { flex: 1; min-width: 0; }
.player-chapter { margin: 0; font: 500 .82rem/1.4 var(--sans); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.player .player-stage { font: .58rem/1.8 var(--sans); letter-spacing: .12em; }
.player .player-exit { font-size: 1.7rem; border: 1px solid var(--rule); border-radius: 50%; }
.player .bar-track { width: min(100%, 76rem); }
.player .player-tools { gap: 1.1rem; }
.player .stepper-meta { gap: 1rem; }
.player .stepper-status { font-size: .68rem; }
.player .text-button { font-size: .73rem; }
.chapter-controls { display: flex; align-items: center; justify-content: space-between; width: min(100%, 46rem); margin: .6rem auto; font: .72rem var(--sans); }
.chapter-controls details { padding: 0; margin: 0; background: none; }
.chapter-controls summary { cursor: pointer; font: 500 .72rem/1.7 var(--sans); color: var(--accent); }
.chapter-controls details[open] > :not(summary) { position: absolute; z-index: 23; top: 100%; max-height: 60vh; overflow-y: auto; padding: 1.3rem; background: var(--surface); border: 1px solid var(--rule); width: min(33rem, calc(100vw - 2rem)); }
.contents-list { left: max(1rem, calc(50% - 23rem)); }
.lesson-options .progress-panel { right: max(1rem, calc(50% - 23rem)); margin: 0; }
.contents-topic { display: block; width: 100%; padding: .75rem; text-align: left; background: none; border: 0; border-bottom: 1px solid var(--rule); color: var(--text); cursor: pointer; font: 1.15rem var(--serif); }
.contents-topic small { display: block; margin-top: .35rem; color: var(--muted); font: .65rem var(--sans); }
.contents-topic:hover, .contents-topic[aria-current] { background: var(--tint); }
.player.prose-page main { width: min(100% - 3rem, 44rem); padding-top: 10rem; }
.topic-position { font: .65rem/1.6 var(--sans); letter-spacing: .05em; color: var(--muted); border-bottom: 1px solid var(--rule); padding-bottom: 1rem; margin-bottom: 2.25rem; }
.stepper:not(.is-stepping) .topic-position { display: none; }
.player.prose-page main .step h3 { font-size: 2.3rem; margin-top: 0; letter-spacing: -.025em; }
.player .stepper.is-stepping .step.is-current { font-size: 1.28rem; line-height: 1.75; }
.player .step-label { font-size: .72rem; margin-bottom: 1.5rem; color: var(--accent); }
.admonition { padding: 1.3rem 1.5rem; }
.admonition-title { padding: 0; border-radius: 0; background: transparent; color: var(--accent); font-size: .65rem; letter-spacing: .12em; }
.question-card { background: transparent; border: 0; border-top: 1px solid var(--rule); padding: 1.5rem 0; border-radius: 0; }
.player .checkpoint-q button[type="submit"] { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); }
.player .checkpoint-q button[type="submit"]:focus-visible { position: absolute; width: auto; height: auto; clip-path: none; z-index: 1; }
.player .question-count { display: none; }
.player .stepper-nav { border-radius: 0; border-top: 1px solid var(--rule); padding-top: 1rem; }
.player .nav-row .button { border-radius: var(--radius); font-size: .85rem; }
.player .rail { background: var(--bg); }
.chapter-next { padding-block: 1.5rem; border-bottom: 1px solid var(--rule); margin-bottom: 2rem; }
.chapter-next > a { font: 1.6rem/1.3 var(--serif); }
.end-heading { margin-bottom: 2.5rem; }
.end-heading h2 { margin-top: 0 !important; font-size: 2.8rem; }
.celebration .confetti { display: none; }
body:not(.player) .chapter-controls { position: relative; }
@media(min-width: 100rem) { .hero { padding-block: 6.5rem 5rem; } }
@media(max-width: 65rem) { .wrap { width: min(100% - 3rem, 78rem); } .hero { gap: 2.5rem; } .hero h1 { font-size: 5rem; } .hero .actions { align-items: flex-start; flex-direction: column; gap: 1rem; } .plate-top { font-size: .45rem; } .course-intro { gap: 3rem; } .player .stepper-status { max-width: 12rem; white-space: normal; } }
@media(max-width: 45rem) {
.wrap { width: calc(100% - 2.5rem); }
.site-header .bar { min-height: 86px; }
.wordmark { font-size: 1rem; gap: .5rem; }
.brand-symbol { width: 42px; height: 42px; }
.site-header nav { gap: 1rem; }
.site-header nav > a { font-size: .7rem; }
.site-header nav > a:nth-of-type(2) { display: none; }
.hero { grid-template-columns: 1fr; padding-block: 3rem; gap: 2.75rem; }
.hero h1 { font-size: clamp(4rem, 17vw, 6rem); }
.hero .lead { font-size: 1.14rem; }
.hero .actions { flex-direction: row; flex-wrap: wrap; align-items: center; }
.orbital-plate { max-width: 31rem; width: calc(100% - .5rem); margin-inline: auto; padding: 1rem; }
.availability { display: block; padding-block: 1rem; }
.availability p + p { margin-top: .5rem; font-size: .62rem; }
.home-course { padding-block: 3rem; }
.section-heading { margin-bottom: 2rem; align-items: flex-start; }
.section-heading .text-link { font-size: .7rem; }
.course-intro { grid-template-columns: 1fr; gap: 1rem; }
.course-intro h2 { font-size: 3rem; }
.lesson-preview a { grid-template-columns: 2.5rem 1fr auto; gap: .75rem; padding-block: 1.25rem; }
.lesson-preview h3 { font-size: 1.45rem; }
.steps { grid-template-columns: 1fr; gap: 1.5rem; }
.method-number { margin-bottom: 1rem; }
.about { grid-template-columns: 1fr; gap: 1.5rem; }
.about h2 { font-size: 3rem; }
.site-footer .wrap { display: block; }
.series-hero { padding-block: 3rem; }
.series-hero h1 { font-size: 3.5rem; }
.key-numbers { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
.chapter-card { grid-template-columns: 1fr; gap: .5rem; }
.chapter-card .card-goal { grid-column: 1; grid-row: auto; }
.chapter-card h3 { font-size: 1.6rem; }
.chapter-card .chips { margin-top: .5rem; }
.player .stepper-top { padding: .65rem .8rem 0; }
.player .player-bar { flex-wrap: wrap; gap: .5rem; }
.player-identity { flex-basis: calc(100% - 3.5rem); }
.player .player-tools { width: 100%; justify-content: space-between; gap: .5rem; }
.player .stepper-meta { flex: 1; justify-content: space-between; gap: .5rem; }
.player .stepper-status { position: static; width: auto; height: auto; overflow: visible; clip-path: none; max-width: none; font-size: .58rem; }
.player .text-button { font-size: .66rem; }
.player .player-tools .theme-toggle { width: 1.8rem; height: 1.8rem; }
.player .player-chapter { font-size: .74rem; }
.player .chapter-controls { margin-block: .4rem; }
.player.prose-page main { width: calc(100% - 2.5rem); padding-top: 11rem; }
.topic-position { font-size: .6rem; margin-bottom: 1.5rem; }
.player .stepper.is-stepping .step.is-current { font-size: 1.16rem; }
.player.prose-page main .step h3 { font-size: 1.9rem; }
.admonition { padding: 1rem; }
.katex { font-size: 1.04em; }
}
@media print { .chapter-controls, .topic-position { display: none !important; } .player.prose-page main { padding-top: 0; } .orbital-plate { transform: none; } }
@media(prefers-reduced-motion: reduce) { a { transition: none; } }

/* Plate illustration and interface icons have independent sizing. */
.hero-figure.orbital-plate .lucide { display: inline-block; width: 1em; height: 1em; margin: 0 0 0 .3em; vertical-align: middle; }
.hero-figure.orbital-plate svg text { fill: currentColor; }
.hero-figure.orbital-plate svg g[font-family="monospace"] text { font: 10px monospace; letter-spacing: 2px; }
.hero-figure.orbital-plate svg g[font-family="Georgia,serif"] text { font-family: Georgia,serif; font-style: italic; }
.hero-figure.orbital-plate svg text[font-size="28"] { font-size: 28px; }
.hero-figure.orbital-plate svg text[font-size="18"] { font-size: 18px; }
.player .stepper-meta { align-items: center; }
.player .topic-position { display: block; }
.player .stepper-status { white-space: nowrap; }
.player .stepper.is-stepping .step.is-current { animation-duration: .18s; }
@media(max-width:45rem) {
 .player .stepper-status { position: static; width: auto; height: auto; clip-path: none; overflow: visible; white-space: normal; }
 .player .stepper-meta { margin: 0; }
 .player.prose-page main { padding-top: 10.5rem; }
 .player .player-tools { flex-wrap: nowrap; }
 .player .katex-display { font-size: .92em; }
}

/* Utility controls stay visually quiet on introduction pages. */
body:not(.player) .calc-toggle { background: var(--bg); color: var(--muted); border-color: var(--rule); border-radius: var(--radius); padding: .5rem .8rem; font: .75rem var(--sans); }
.player .calc-toggle { border-radius: var(--radius); font: .75rem var(--sans); }

/* Keep the progress strip inside its stage widths in long chapters. */
.player .bar-ticks { gap: 0; }
.player .tick { min-width: 0; }

/* Lessons are an open canvas. Only controls need a boundary. */
.player .stepper-top { padding: 1rem 1.25rem 0; border: 0; }
.player .player-bar, .player .bar-track { width: min(100%, 62rem); }
.player .player-bar { flex-wrap: nowrap; min-height: 2.5rem; }
.player .player-identity { flex: 1; }
.player .player-chapter { font-size: .85rem; }
.player .player-stage { display: none; }
.player .player-exit { border: 0; }
.player .chapter-controls { width: auto; margin: 0; flex: none; }
.player .lesson-options { position: relative; }
.player .lesson-options > summary { padding: .6rem .2rem .6rem .8rem; color: var(--muted); font-size: .8rem; }
.player .lesson-options[open] > .progress-panel { top: calc(100% + .75rem); right: 0; width: min(29rem, calc(100vw - 2.5rem)); max-height: calc(100svh - 7rem); display: flex; flex-direction: column; align-items: stretch; gap: 1rem; }
.player .menu-chapter { font: 600 1rem/1.5 var(--sans); color: var(--text); }
.player .player-tools { display: flex; width: auto; flex-wrap: wrap; gap: 1rem; }
.player .stepper-meta { flex-basis: 100%; flex-wrap: wrap; }
.player .stepper-status { font-size: .75rem; }
.player .lesson-contents[open] > .contents-list { position: static; width: 100%; max-height: 35vh; padding: 0; margin-top: .5rem; border: 0; }
.player .calc-toggle { position: static; padding: .4rem .6rem; transform: none; background: transparent; color: var(--text); }
.player.prose-page main { width: min(100% - 3rem, 42rem); padding: 7.5rem 0 8rem; }
.player .topic-position { padding: 0; margin: 0 0 1rem; border: 0; font-size: .7rem; }
.player .stepper.is-stepping .step.is-current { display: flex; flex-direction: column; justify-content: center; min-height: calc(100svh - 18rem); margin: 0; }
.player .stepper.is-stepping .step.is-current > * { flex-shrink: 0; }
.player .stepper.is-stepping .step-label { display: none; }
.player .part-break { display: none; }
.player .admonition, .player .question-card, .player .history-card, .player .variant-box, .player .q-reveal { background: transparent; border: 0; padding: 0; }
.player .admonition.abstract .admonition-title { display: none; }
.player .admonition.abstract > p:not(.admonition-title) { font-size: 1.2em; line-height: 1.5; }
.player .stepper-nav { border: 0; width: min(100%, 32rem); padding: .8rem 1.25rem calc(.8rem + env(safe-area-inset-bottom, 0px)); }
.player .nav-row .button.ghost { border: 0; color: var(--muted); padding-inline: .5rem 1rem; }
.player .nav-row .button:not(.ghost) { min-height: 3.25rem; }
.player .stepper.is-continuing .step.is-current { animation: none; }
.player .stepper.is-pausing .step.is-current, .player .stepper.is-pausing .tier-nav, .player .stepper.is-pausing .topic-position { display: none; }
.topic-pause { padding-top: 12vh; }
.topic-pause h2 { font-size: clamp(2rem, 5vw, 3rem); line-height: 1.15; }
.q-hint { display: inline-block; margin: .6rem 0; }
.walk-experiment { margin: 0; width: 100%; }
.walk-experiment figcaption { font-size: 1rem; line-height: 1.65; }
.walk-scene svg { display: block; width: 100%; height: auto; max-height: 14rem; overflow: visible; }
.walk-scene svg text { font: 18px var(--sans); fill: var(--muted); }
.walk-axis { stroke: var(--rule); stroke-width: 1; }
.walk-person { stroke: var(--accent); stroke-width: 3; fill: var(--accent); stroke-linecap: round; }
.walk-start { fill: var(--muted); }
.walk-out, .walk-back, .walk-net { fill: none; stroke-width: 3; opacity: 0; }
.walk-out { stroke: var(--track-physics); }
.walk-back { stroke: var(--track-maths); }
.walk-net { stroke: var(--accent); stroke-dasharray: 4 4; }
.walk-finished .walk-out, .walk-finished .walk-back, .walk-finished .walk-net { opacity: 1; }
.walk-readout { font: .85rem/1.6 var(--sans); text-align: center; color: var(--muted); min-height: 2.7em; margin: .5rem 0; }
.walk-actions { text-align: center; margin-bottom: 1rem; }
.walk-principle { font-size: 1.4rem; }
.walk-slider { display: flex; align-items: center; flex-wrap: wrap; gap: .75rem; font: .85rem var(--sans); margin: 1.5rem 0; }
.walk-slider input { flex: 1; min-width: 6rem; min-height: 2.75rem; accent-color: var(--accent); }
.walk-slider output { min-width: 3rem; }
.home-experiment { display: grid; grid-template-columns: 1fr 1fr; gap: 5rem; padding-block: 4rem; border-bottom: 1px solid var(--rule); align-items: center; }
.home-experiment h2 { font-size: clamp(2.2rem, 4vw, 3.6rem); }
.home-experiment > div > p:not(.eyebrow) { color: var(--muted); max-width: 28rem; }
.home-experiment .q-option { font-size: .9rem; }
.home-experiment .q-reveal { background: transparent; padding: 0; }
.continue-learning { display: flex; align-items: center; gap: 1.5rem; padding-top: 2rem; flex-wrap: wrap; }
.continue-learning p { margin: 0; }
.review-chapter { margin-top: 3rem; }
.review-list { list-style: none; padding: 0; }
.review-list li { display: flex; flex-direction: column; gap: .3rem; padding: 1rem 0; border-bottom: 1px solid var(--rule); }
.player [data-journey][data-phase="predict"] > .journey-investigation,
.player [data-journey][data-phase="predict"] > .journey-explanation,
.player [data-journey][data-phase="explore"] > .journey-prediction,
.player [data-journey][data-phase="explore"] > .journey-explanation,
.player [data-journey][data-phase="explain"] > .journey-prediction { display: none; }
.journey-prediction > .eyebrow, .journey-investigation > .eyebrow, .journey-explanation > .eyebrow { margin: 0 0 1rem; }
.journey-investigation, .journey-explanation { margin-top: 2rem; }
.player .journey-investigation { margin-top: 0; }
.investigation-task { font-size: 1.1em; line-height: 1.6; }
.journey-prediction .q-prompt { font-size: 1.15em; margin-bottom: 1.25rem; }
.journey-prediction .q-option { font-size: .95rem; min-height: 3rem; align-items: center; }
.lesson-model { margin: 2rem 0 0; }
.lesson-model figcaption { font: 600 1.1rem/1.5 var(--sans); color: var(--text); }
.model-visual svg { display: block; width: 100%; max-height: 18rem; margin: .5rem auto; }
.model-line, .model-guide, .model-vector, .model-secondary { fill: none; stroke: var(--text); stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.model-guide { stroke: var(--rule); stroke-dasharray: 4 4; }
.model-vector { stroke: var(--accent); stroke-width: 3; }
.model-secondary { stroke: var(--track-physics); stroke-width: 3; }
.model-dot, .model-fill { fill: var(--accent); }
.model-other-fill, .model-central { fill: var(--track-physics); }
.model-body { fill: var(--surface); stroke: var(--text); stroke-width: 2; }
.model-visual text { fill: var(--muted); font: 15px var(--sans); }
.model-controls { display: grid; gap: .75rem; }
.model-controls { margin-top: 1rem; }
.model-controls label { display: grid; grid-template-columns: minmax(8rem, 1fr) 1.5fr 4.5rem; align-items: center; gap: .75rem; font: .85rem/1.5 var(--sans); }
.model-controls input { width: 100%; min-height: 2.75rem; accent-color: var(--accent); }
.model-controls output { text-align: right; font-variant-numeric: tabular-nums; }
.model-readouts { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; margin: 1.5rem 0 0 !important; font-family: var(--sans); }
.model-readouts dt { margin: 0 !important; font-size: .75rem; font-weight: 400 !important; color: var(--muted); }
.model-readouts dd { font-size: 1.2rem; line-height: 1.7; font-variant-numeric: tabular-nums; }
.model-assumptions { margin: 1rem 0 0; color: var(--muted); font: .75rem/1.6 var(--sans); }
.model-notes { padding: 0; background: transparent; margin: 1rem 0; }
.model-notes > summary { font: .75rem/1.6 var(--sans); color: var(--muted); }
.model-settings { display: none; margin: .5rem 0; font: .8rem/1.6 var(--sans); color: var(--muted); }
.player [data-journey][data-phase="explain"] .model-settings { display: block; }
.player [data-journey][data-phase="explain"] .journey-investigation > .eyebrow,
.player [data-journey][data-phase="explain"] .investigation-task,
.player [data-journey][data-phase="explain"] .model-controls { display: none; }
.player [data-journey][data-phase="explain"] .lesson-model { margin-top: 0; }
.topic-recall { font-size: 1.15em; }
@media(max-width: 45rem) {
 .player .player-identity { flex-basis: auto; }
 .player .player-chapter { font-size: .75rem; white-space: normal; }
 .player.prose-page main { width: calc(100% - 2.5rem); padding-top: 6.5rem; }
 .player .stepper.is-stepping .step.is-current { min-height: calc(100svh - 16rem); }
 .player .stepper-meta { flex-wrap: wrap; }
 .player .player-tools { flex-wrap: wrap; }
 .player .lesson-options > summary { font-size: .7rem; white-space: nowrap; }
 .home-experiment { grid-template-columns: 1fr; gap: 2rem; padding-block: 3rem; }
 .continue-learning { gap: .8rem; }
 .continue-learning .note { flex-basis: 100%; }
 .walk-experiment figcaption { font-size: 1rem; }
 .model-controls label { grid-template-columns: 1fr 5rem; gap: .25rem .75rem; }
 .model-controls label input { grid-row: 2; grid-column: 1 / -1; }
 .model-controls output { grid-row: 1; grid-column: 2; }
 .model-visual text { font-size: 18px; }
 .journey-prediction .q-option { font-size: .9rem; }
 .investigation-task { font-size: 1rem; line-height: 1.6; }
 .model-visual svg { max-height: 10rem; }
 .model-readouts { gap: .5rem 1rem; }
 .model-readouts dd { font-size: 1.05rem; }
}
@media print {
 .player .stepper.is-stepping .step.is-current { display: block; min-height: 0; }
 .topic-pause, .walk-actions, .walk-slider { display: none; }
 .walk-out, .walk-back, .walk-net { opacity: 1; }
 .player .stepper.is-pausing .step.is-current { display: block; }
 .player [data-journey] > .journey-prediction, .player [data-journey] > .journey-investigation, .player [data-journey] > .journey-explanation { display: block !important; }
 .model-controls { display: none; }
}