@charset "UTF-8";
:root{color-scheme:dark;--bg:#171c21;--panel:#20282e;--line:#465057;--gold:#e4bd7d;--cream:#f7f1e6;--muted:#c0c8cd;--ink:#282d30;--paper:#f4eee3;--green:#acd7b9}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--cream);font:1.0625rem/1.65 system-ui,-apple-system,"Segoe UI",sans-serif}button,a,input,summary{-webkit-tap-highlight-color:transparent}button,input{font:inherit}button,summary{cursor:pointer}button{color:inherit}a{color:var(--gold);text-underline-offset:4px}button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid var(--gold);outline-offset:5px}button{border:1px solid var(--line);border-radius:6px;background:transparent;min-height:48px;padding:.7rem 1.05rem}button:hover{border-color:var(--gold);background:#2b343b}button:disabled{opacity:.4;cursor:default}button[aria-pressed=true]{border-color:var(--gold);background:#3c352a}button[aria-pressed=true] .choice-mark{color:var(--gold)}[hidden]{display:none!important}.course-shell{max-width:1280px;margin:auto;padding:0 40px}.topbar{display:flex;align-items:center;justify-content:space-between;gap:24px;padding:22px 0;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--cream);font-family:Georgia,serif;font-size:1.2rem}.brand small{display:block;font: .875rem/1.6 system-ui,sans-serif;color:var(--muted)}.quiet{border-color:transparent;font-size:.9375rem}.chapterline{display:flex;justify-content:space-between;gap:20px;color:var(--muted);font-size:.875rem;padding:23px 0}.chapterline>span:first-child{color:var(--gold)}main{min-height:470px;padding:12px 0 22px}main:focus{outline:none}.eyebrow{font-size:.875rem;letter-spacing:.15em;text-transform:uppercase;color:var(--gold);margin:0 0 16px}h1,h2,h3,p{margin-top:0}h1{font:normal clamp(2.1rem,4.1vw,3.9rem)/1.08 Georgia,serif;letter-spacing:-.025em;max-width:940px;margin-bottom:22px;text-wrap:balance}h2{font:normal 2rem/1.2 Georgia,serif}h3{font-size:1.15rem;line-height:1.4}p{margin-bottom:1.1rem}.lede{font-size:1.125rem;color:#dce0e1;max-width:780px}.split{display:grid;grid-template-columns:1.1fr 1fr;gap:42px;align-items:center}.opening h1{font-size:clamp(2.6rem,4.3vw,4.2rem)}.opening-art{width:100%;aspect-ratio:1.1;object-fit:cover;border-radius:3px}.gold{color:var(--gold)}.opening .gatekeepers{border-left:2px solid var(--gold);padding-left:20px;color:var(--muted);margin:24px 0}.primary{background:var(--gold);border-color:var(--gold);color:#231e18;font-weight:650}.primary:hover{background:#f2d5a5;color:#231e18}.course-footer{display:flex;align-items:center;justify-content:space-between;gap:24px;padding:23px 0;border-top:1px solid var(--line)}.progress-wrap{min-width:120px;text-align:center;font-size:.875rem;color:var(--muted)}progress{display:block;width:170px;height:4px;margin-top:10px;border:0;background:#38424a;accent-color:var(--gold)}progress::-webkit-progress-bar{background:#38424a}progress::-webkit-progress-value{background:var(--gold)}.extras{display:flex;align-items:start;justify-content:space-between;gap:24px;padding:14px 0 20px;color:var(--muted);font-size:.9375rem}.extras details{flex:1;max-width:850px}summary{padding:8px 0;min-height:44px}.extras details[open]{width:100%}#narration-copy{padding:18px 0;max-width:760px;color:#dce0e1}#sources{max-width:380px;font-size:.875rem}#sources a{display:inline-block;margin:8px 12px 0 0}.contents{padding:18px 0;border-bottom:1px solid var(--line);display:grid;grid-template-columns:repeat(3,1fr);gap:8px}.contents button{text-align:left;font-size:.9375rem}.contents button[aria-current=step]{border-color:var(--gold);color:var(--gold)}.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.grid.two{grid-template-columns:repeat(2,1fr)}.choice{text-align:left;display:flex;align-items:center;gap:15px;padding:16px 18px;background:#20282e}.choice strong,.choice small{display:block}.choice small{font-size:.9375rem;color:var(--muted);margin-top:5px}.choice-mark{font-size:1.2rem;width:24px;flex-shrink:0;color:#89959d}.feedback{background:#293b36;border-left:3px solid var(--green);padding:18px 22px;margin:22px 0 0}.feedback p:last-child{margin-bottom:0}.feedback.retry{background:#3d3028;border-color:var(--gold)}.paper{background:var(--paper);color:var(--ink);padding:32px;border-radius:3px}.paper .eyebrow{color:#755329}.paper a{color:#644717}.quote{font:normal clamp(1.6rem,2.8vw,2.6rem)/1.3 Georgia,serif}.center{text-align:center}.fact{font:normal clamp(3rem,6vw,5.8rem)/1.1 Georgia,serif;color:var(--gold)}.panel{background:var(--panel);border:1px solid var(--line);padding:26px;border-radius:5px}.pill{display:inline-block;padding:4px 12px;border:1px solid var(--line);border-radius:30px;font-size:.875rem;color:var(--muted)}.timeline{display:flex;gap:0;margin:24px 0 30px;align-items:center}.timeline button{flex:1;border-radius:0;border-width:0 0 2px;font-size:1rem}.timeline button.active{border-color:var(--gold);color:var(--gold)}.range{width:100%;accent-color:var(--gold);min-height:44px;cursor:pointer}.range-labels{display:flex;justify-content:space-between;font-size:.9375rem;color:var(--muted)}.bar-row{margin:18px 0}.bar-label{display:flex;justify-content:space-between;gap:15px}.bar-track{height:14px;background:#3c464e;margin-top:8px}.bar-fill{height:100%;background:var(--gold);width:var(--value)}.note{font-size:.9375rem;color:var(--muted)}.paper .note{color:#50555a}.readable{max-width:840px}.stack{display:grid;gap:12px}.stat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px;margin:30px 0}.stat-grid .fact{font-size:clamp(2.5rem,4.5vw,4.5rem)}.stat-grid p{font-size:1rem;color:var(--muted)}.compare{display:grid;grid-template-columns:1fr 1fr;gap:22px}.compare ul{padding-left:20px}.compare li{margin:10px 0}.editorial{color:#a73832}.editorial-list{display:flex;flex-wrap:wrap;gap:10px;margin-top:20px}.editorial-list span{background:#f7e3df;border:1px solid #b85849;padding:8px 14px;color:#7a251e}.big-equation{display:flex;align-items:center;justify-content:center;gap:30px;font:normal clamp(1.6rem,3.5vw,3rem)/1.2 Georgia,serif;margin:36px 0}.big-equation b{color:var(--gold);font-size:1.7em}.skip{position:absolute;left:-9999px;background:var(--paper);color:var(--ink);padding:12px;z-index:99}.skip:focus{left:20px;top:10px}.noscript{padding:30px}.lesson-in{animation:enter .35s ease both}@keyframes enter{from{opacity:0;transform:translateY(7px)}to{opacity:1;transform:none}}.compact{margin-bottom:0}.reason-summary{color:var(--gold);font-weight:600}.complete-mark{font-size:3rem;color:var(--green)}
@media(max-width:800px){.course-shell{padding:0 22px}.split{gap:24px;grid-template-columns:1fr}.opening{grid-template-columns:1.25fr 1fr}.opening h1{font-size:2.7rem}.opening-art{aspect-ratio:.8}.grid{grid-template-columns:repeat(2,1fr)}.contents{grid-template-columns:repeat(2,1fr)}main{min-height:440px}.stat-grid{gap:15px}.paper{padding:24px}.course-footer{gap:12px}.course-footer .primary{max-width:250px}.extras{flex-direction:column;gap:0}#sources{max-width:none}}
@media(max-width:560px){.course-shell{padding:0 18px}.topbar{gap:10px;padding:15px 0}.brand{font-size:1rem}.brand small{font-size:.8125rem;max-width:190px}.brand img{display:none}#contents-button{font-size:.875rem;max-width:125px;padding:6px}.chapterline{font-size:.8125rem;gap:10px}.chapterline>span:last-child{text-align:right}.opening{grid-template-columns:1fr}.opening h1{font-size:2.7rem}.opening-art{aspect-ratio:1.7;max-height:250px;object-position:center 60%}.grid,.grid.two,.compare,.contents{grid-template-columns:1fr}.stat-grid{grid-template-columns:1fr}.stat-grid>div{display:flex;align-items:center;gap:18px}.stat-grid .fact{min-width:135px}.stat-grid p{margin:0}.timeline{flex-wrap:wrap}.timeline button{min-width:30%;font-size:.9375rem;padding:.6rem}.big-equation{gap:12px;font-size:1.5rem}.course-footer{flex-wrap:wrap}.progress-wrap{order:-1;width:100%;display:flex;justify-content:space-between;gap:20px;align-items:center}progress{margin:0;width:45%}.course-footer .primary{max-width:75%;font-size:.9375rem}.course-footer .quiet{padding-left:0}.choice{padding:14px}.paper{padding:22px}.quote{font-size:1.65rem}}
.paper .range-labels{color:#50555a}.course-footer{position:sticky;bottom:0;background:var(--bg);z-index:5}.extras{padding-bottom:24px}.extras>#listen{flex-shrink:0}.big-equation{flex-wrap:wrap}.stat-grid>div{min-width:0}.stat-grid .fact{overflow-wrap:anywhere}.topbar{flex-wrap:wrap}.chapterline{flex-wrap:wrap}button{overflow-wrap:anywhere}
@media(max-width:560px){.stat-grid>div{flex-wrap:wrap}.stat-grid .fact{margin-bottom:0}.stat-grid p:last-child{flex:1;min-width:130px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}

/* Recorded narration */
.extras{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:16px 24px}
.narration-player{grid-column:1/-1;background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:16px 20px}
.audio-heading{display:flex;flex-wrap:wrap;align-items:baseline;justify-content:space-between;gap:4px 20px;margin-bottom:10px}
.audio-heading strong{color:var(--cream)}
.audio-controls{display:flex;align-items:center;flex-wrap:wrap;gap:10px}
.audio-controls audio{width:450px;max-width:100%;min-width:0;height:48px;flex:0 1 450px}
.audio-controls button{flex:0 0 auto}
.optional-narration{border-bottom:1px solid var(--line);padding-bottom:20px;margin-bottom:20px}
.optional-narration>p:first-child{margin-bottom:10px}
.narration-player [role=status]:empty,.optional-narration [role=status]:empty{display:none}
@media(max-width:800px){.extras{grid-template-columns:minmax(0,1fr)}.extras #sources{max-width:100%}}
@media(max-width:560px){.narration-player{padding:14px}.audio-controls audio{flex-basis:100%}}