@font-face{font-family:"Literata";src:url(fonts/literata-latin.woff2) format("woff2");font-weight:200 900;font-display:swap;unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+2000-206F,U+2074,U+20AC,U+2122,U+2191-2199,U+2212,U+2215,U+FEFF,U+FFFD}
@font-face{font-family:"Literata";src:url(fonts/literata-latin-ext.woff2) format("woff2");font-weight:200 900;font-display:swap;unicode-range:U+0100-02AF,U+0304,U+0308,U+0329,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}
@font-face{font-family:"Plex";src:url(fonts/ibmplexsans-400-lat.woff2) format("woff2");font-weight:400;font-display:swap;unicode-range:U+0000-00FF,U+2000-206F,U+2190-2199}
@font-face{font-family:"Plex";src:url(fonts/ibmplexsans-400-ext.woff2) format("woff2");font-weight:400;font-display:swap;unicode-range:U+0100-02AF,U+1E00-1EFF}
@font-face{font-family:"Plex";src:url(fonts/ibmplexsans-600-lat.woff2) format("woff2");font-weight:600;font-display:swap;unicode-range:U+0000-00FF,U+2000-206F,U+2190-2199}
@font-face{font-family:"Plex";src:url(fonts/ibmplexsans-600-ext.woff2) format("woff2");font-weight:600;font-display:swap;unicode-range:U+0100-02AF,U+1E00-1EFF}

:root{
  --bg:#f3ece0;--paper:#faf6ec;--ink:#211a12;--mut:#6b5f4e;--line:#d8cdb8;
  --core:#b3401e;--core-deep:#7e2a12;--prem:#0f6b6b;--prem-deep:#0a4a4a;
  --sea:#cfdde4;--land:#8aa583;--focus:#0f6b6b;--bar:rgba(243,236,224,.92);
  --ly-mantle:#c96f3b;--ly-outer:#e09a3c;--ly-inner:#f2cf6b;--tun:#211a12;--oncore:#fff;
  --serif:"Literata",Georgia,serif;--sans:"Plex",system-ui,-apple-system,"Segoe UI",sans-serif;
  color-scheme:light;
}
:root[data-theme="dark"]{
  --bg:#171310;--paper:#221b15;--ink:#f0e8da;--mut:#b3a68f;--line:#3a3128;
  --core:#f08a62;--core-deep:#f0a58a;--prem:#5fc4c4;--prem-deep:#8ad8d8;
  --sea:#1d2a33;--land:#4a6b52;--focus:#8ad8d8;--bar:rgba(23,19,16,.92);
  --ly-mantle:#8a4a26;--ly-outer:#a86e28;--ly-inner:#c9a24a;--tun:#f0e8da;--oncore:#171310;
  color-scheme:dark;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#171310;--paper:#221b15;--ink:#f0e8da;--mut:#b3a68f;--line:#3a3128;
  --core:#f08a62;--core-deep:#f0a58a;--prem:#5fc4c4;--prem-deep:#8ad8d8;
  --sea:#1d2a33;--land:#4a6b52;--focus:#8ad8d8;--bar:rgba(23,19,16,.92);
  --ly-mantle:#8a4a26;--ly-outer:#a86e28;--ly-inner:#c9a24a;--tun:#f0e8da;--oncore:#171310;
  color-scheme:dark;
}}

*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{margin:0;background:var(--bg);color:var(--ink);font:400 1.08rem/1.62 var(--serif);font-optical-sizing:auto;overflow-x:clip}
a{color:var(--core-deep);text-underline-offset:.15em}
:where(:root[data-theme="dark"]) a{color:var(--core)}
@media (prefers-color-scheme:dark){:where(:root:not([data-theme="light"])) a{color:var(--core)}}
a:focus-visible,button:focus-visible,select:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid var(--focus);outline-offset:2px;border-radius:4px}
h1,h2,h3{font-family:var(--serif);line-height:1.12;margin:0 0 .5em}
h2{font-size:clamp(1.9rem,4.2vw,3rem);font-weight:600;letter-spacing:-.01em}
h2 .anchor{color:inherit;text-decoration:none}
h3{font-size:1.2rem;font-weight:650}
p{margin:0 0 1em}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.skip{position:absolute;left:-999px;top:0}.skip:focus{left:8px;top:8px;z-index:50;background:var(--paper);padding:.4em .8em}
section{scroll-margin-top:52px;padding:clamp(3rem,8vw,6rem) clamp(16px,5vw,64px);max-width:1280px;margin:0 auto}
.lede{font-size:1.18rem;max-width:40em;color:var(--ink)}
figcaption{font:400 .82rem/1.45 var(--sans);color:var(--mut);margin-top:.55em}
figure{margin:0}
.note{font:400 .88rem/1.5 var(--sans);color:var(--mut);margin-top:1.6rem}
[hidden]{display:none!important}

/* topbar */
.topbar{position:sticky;top:0;z-index:30;display:flex;align-items:center;gap:.9rem;height:46px;padding:0 clamp(12px,3vw,28px);background:var(--bar);backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);border-bottom:1px solid var(--line);font:400 .9rem/1 var(--sans);white-space:nowrap}
.topbar a{color:var(--ink);text-decoration:none}
.home{font-weight:600}
.topnav{display:flex;gap:1rem;overflow-x:auto;scrollbar-width:none;min-width:0}
.topnav::-webkit-scrollbar{display:none}
.topnav a{color:var(--mut);padding:.35em 0}
.topnav a[aria-current="true"]{color:var(--ink);box-shadow:inset 0 -2px var(--core)}
.spacer{flex:1}
.chip{border:1px solid var(--line);border-radius:999px;padding:.35em .8em}
.icon-btn{width:34px;height:34px;border-radius:50%;border:1px solid var(--line);background:transparent;color:var(--ink);display:grid;place-items:center;cursor:pointer;padding:0;flex:none}
.icon-btn svg{display:block}.icon-btn svg[hidden]{display:none}
@media (max-width:560px){.home{display:none}.topnav{gap:.8rem}}

/* progress hairline + rail (the bead falls as you read) */
.progress{position:fixed;top:0;left:0;right:0;height:4px;z-index:40;pointer-events:none}
.progress .hair{position:absolute;inset:0;background:var(--core);transform-origin:0 50%;transform:scaleX(0)}
#railbead{position:absolute;top:-4px;left:0;width:12px;height:12px;border-radius:50%;background:var(--core);border:2px solid var(--bg)}
.rail{position:fixed;right:14px;top:50%;transform:translateY(-50%);z-index:30;display:flex;flex-direction:column;gap:.7rem}
.rail a{width:14px;height:14px;border-radius:50%;border:2px solid var(--mut);display:block}
.rail a[aria-current="true"]{background:var(--core);border-color:var(--core)}
@media (max-width:80rem){.rail{display:none}}

/* hero */
.hero{display:grid;grid-template-columns:1fr 1fr;gap:clamp(1.5rem,5vw,4rem);align-items:center;min-height:calc(100svh - 46px);padding-top:clamp(1.5rem,4vw,3rem)}
.kicker{font:600 .8rem/1.3 var(--sans);letter-spacing:.12em;text-transform:uppercase;color:var(--core-deep);margin-bottom:1.1em}
h1{font-size:clamp(2.3rem,5.5vw,4.4rem);font-weight:700;letter-spacing:-.02em;line-height:1.02;margin-bottom:.35em;max-width:22ch}
.deck{font-size:clamp(1.12rem,1.9vw,1.4rem);line-height:1.5;max-width:31em}
.cta{display:flex;flex-wrap:wrap;gap:.7rem;margin-top:1.2em}
.start{display:inline-flex;align-items:center;gap:.5em;font:600 1rem/1 var(--sans);color:var(--oncore);background:var(--core-deep);text-decoration:none;padding:.85em 1.25em;border-radius:999px;min-height:44px;border:0;cursor:pointer}
.ghost{display:inline-flex;align-items:center;font:600 1rem/1 var(--sans);color:var(--ink);background:transparent;border:1.5px solid var(--line);border-radius:999px;padding:.85em 1.25em;min-height:44px;text-decoration:none;cursor:pointer}
.hero-fig svg{display:block;width:min(100%,calc(72svh));height:auto;margin:0 auto}
.hero-src{font:400 .82rem var(--sans);color:var(--mut);margin-top:.9em}
@media (max-width:820px){.hero{grid-template-columns:1fr;min-height:0}.hero-fig svg{width:min(100%,calc(44svh))}}

/* cross-section scene */
.xsec{display:block;width:min(100%,380px);height:auto;margin:0 auto}
.ly-mantle{fill:var(--ly-mantle)}
.ly-outer{fill:var(--ly-outer)}
.ly-inner{fill:var(--ly-inner)}
.tunnel{stroke:var(--tun);stroke-width:5;stroke-linecap:round}
.bead{stroke:#fff;stroke-width:2}
.bead-u{fill:var(--core)}
.bead-p{fill:var(--prem)}
.chord-line{stroke-width:4}

/* share */
.share{display:flex;align-items:center;flex-wrap:wrap;gap:.6rem 1rem;padding-top:0;padding-bottom:0}
.share-label{font:400 .85rem var(--sans);color:var(--mut)}
.share-row{display:flex;gap:.5rem}
.sh{width:40px;height:40px;border-radius:50%;border:1px solid var(--line);background:transparent;color:var(--ink);display:grid;place-items:center;cursor:pointer;padding:0;text-decoration:none}
.sh:hover,.sh:focus-visible{border-color:var(--core);color:var(--core-deep)}
@media (pointer:coarse){.sh{width:44px;height:44px}}
.copy-note{font:400 .85rem var(--sans);color:var(--mut);min-height:1.2em}

/* town + map */
.picker{display:flex;flex-wrap:wrap;gap:.7rem;align-items:center;margin:1.4rem 0;font:400 1rem var(--sans)}
.picker select,.picker input{font:400 1rem var(--sans);color:var(--ink);background:var(--paper);border:1.5px solid var(--line);border-radius:8px;padding:.7em 1em;min-height:44px;max-width:min(78vw,22em)}
.picker button[type="submit"]{font:600 1rem/1 var(--sans);color:var(--oncore);background:var(--core-deep);border:0;border-radius:999px;padding:.85em 1.4em;min-height:44px;cursor:pointer}
.verdict{font-size:1.25rem;max-width:36em;font-weight:500;border-left:4px solid var(--core);padding-left:1rem}
.mapfig{margin:1.6rem 0 .5rem}
.world{display:block;width:100%;height:auto;border-radius:10px;background:var(--sea)}
.world .sea{fill:var(--sea)}
.world .land{fill:var(--land)}
.dot-town{fill:var(--core);stroke:#fff;stroke-width:1.5}
.dot-anti{fill:var(--prem);stroke:#fff;stroke-width:1.5}
.what{margin-top:1.2rem;font:400 .95rem/1.55 var(--sans)}
.what summary{cursor:pointer;color:var(--ink);font-weight:600;min-height:44px;display:inline-flex;align-items:center}
.what ul{margin:.4em 0 0;padding-left:1.2em;color:var(--mut)}

/* race: sticky scene + steps */
.journey-cols{display:grid;grid-template-columns:7fr 5fr;gap:clamp(1.5rem,4vw,3rem);align-items:start;margin-top:1.6rem}
.map-wrap{position:sticky;top:56px}
.scene-sticky{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:1rem}
.hud{font:600 clamp(1.6rem,3.4vw,2.4rem)/1 var(--serif);font-variant-numeric:tabular-nums;color:var(--core-deep);text-align:center;margin:.6rem 0}
.playrow{display:flex;gap:.7rem;justify-content:center;flex-wrap:wrap}
.steps{display:grid;gap:1.2rem}
.step{background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:1.2rem 1.3rem 1rem;opacity:.55;scroll-margin-top:120px}
.step.on{opacity:1;border-color:var(--core);box-shadow:0 0 0 1px var(--core)}
html:not(.has-js) .step{opacity:1}
.wk{font:600 .8rem/1.4 var(--sans);letter-spacing:.06em;text-transform:uppercase;color:var(--core-deep);margin-bottom:.6em}
.step-btns{display:flex;gap:.6rem;flex-wrap:wrap;margin:.8em 0 0}
@media (max-width:820px){.journey-cols{grid-template-columns:1fr}.map-wrap{position:static}.scene-sticky .xsec{width:min(100%,300px)}}
html.still *,html.still *::before,html.still *::after{transition:none!important}
@media (prefers-reduced-motion:reduce){*{transition:none!important}}

/* guesses */
.guess{background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:1.1rem 1.2rem;margin:1.4rem 0;max-width:40em}
.guess-q{font-weight:600;margin-bottom:.6em}
.guess-btns{display:flex;gap:.6rem;flex-wrap:wrap}

/* tables */
.tablewrap{overflow-x:auto;margin-top:.6rem}
table{border-collapse:collapse;min-width:30em}
th{font:600 .85rem var(--sans);text-align:left;color:var(--mut);padding:.4em 1em .4em 0;border-bottom:2px solid var(--line)}
td{border-bottom:1px solid var(--line);padding:.45em 1em .45em 0;font-variant-numeric:tabular-nums}

/* curves */
.curvefig{margin:1.2rem 0}
.curves{display:block;width:100%;height:auto;background:var(--paper);border:1px solid var(--line);border-radius:10px}
.curves .grid{stroke:var(--line);stroke-width:1}
.ylab{font:400 12px var(--sans);fill:var(--mut);text-anchor:end}
.cv-u{fill:none;stroke:var(--core);stroke-width:2.5}
.cv-p{fill:none;stroke:var(--prem);stroke-width:2.5}
.cv-dot-u{fill:var(--core);stroke:#fff;stroke-width:1.5}
.cv-dot-p{fill:var(--prem);stroke:#fff;stroke-width:1.5}

/* walls + kola */
.cgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(270px,1fr));gap:1.2rem;margin-top:1.6rem}
.cause{background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:1.3rem 1.4rem}
.bsrc{font:400 .8rem/1.4 var(--sans);color:var(--mut);margin:.8em 0 0}
.kolabar{margin:1.6rem 0;max-width:44em}
.kb-row{display:grid;grid-template-columns:6em 1fr auto;gap:.7rem;align-items:center;margin-bottom:.6rem;font:400 .9rem var(--sans)}
.kb-track{background:var(--paper);border:1px solid var(--line);border-radius:6px;height:22px;position:relative;overflow:hidden}
.kb-fill{position:absolute;top:0;bottom:0;left:0;background:var(--core)}
.kb-diam{width:100%}
.kb-kola{width:2px}
.kb-val{font-variant-numeric:tabular-nums;color:var(--mut)}

/* quiz */
.qlist{display:grid;gap:1.2rem;margin-top:1.4rem}
.q{background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:1.2rem 1.3rem;scroll-margin-top:70px}
.qq{font-size:1.1rem;font-weight:600}
.qn{display:inline-grid;place-items:center;width:1.7em;height:1.7em;border-radius:50%;background:var(--core-deep);color:var(--oncore);font:600 .85rem var(--sans);margin-right:.5em}
.opts{list-style:none;padding:0;margin:.8em 0 0;display:grid;gap:.5rem}
.opt{font:400 1rem var(--sans);color:var(--ink);background:transparent;border:1.5px solid var(--line);border-radius:8px;padding:.7em 1em;min-height:44px;cursor:pointer;text-align:left;width:100%}
.guess-btns .opt{width:auto}
.opt.picked{border-color:var(--core)}
.opt.right{border-color:#2e7d43;background:rgba(46,125,67,.12)}
.opt.wrong{border-color:#b3261e;background:rgba(179,38,30,.10)}
.qfb{font:400 .92rem var(--sans);margin:.7em 0 0}
.score{font:600 1.2rem var(--serif);min-height:1.6em}
.qkey{font:400 .95rem var(--sans);color:var(--mut)}

/* faq */
.faqsec details{background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:.9rem 1.1rem;margin-bottom:.7rem}
.faqsec summary{cursor:pointer;font-weight:600;min-height:44px;display:flex;align-items:center}
.faqsec p{margin:.6em 0 0}

/* method + sources + footer */
.method p,.src p{max-width:52em}
.src{font:400 .95rem/1.6 var(--sans);color:var(--mut)}
.src h2,.src h3{color:var(--ink)}
.sgroup{margin-bottom:1.4rem}
.sgroup ul{padding-left:1.2em;margin:.4em 0}
.sgroup li{margin-bottom:.3em}
.src a,.method p{overflow-wrap:anywhere}
.atlas{font:400 .95rem var(--sans);color:var(--mut)}
.foot{padding:2rem clamp(16px,5vw,64px) 3rem;font:400 .85rem var(--sans);color:var(--mut);border-top:1px solid var(--line);max-width:1280px;margin:0 auto}
.foot a{color:var(--mut)}
.nf main{max-width:40em;margin:20vh auto;padding:0 16px}

@media (max-width:560px){
  .picker select,.picker input{max-width:100%;width:100%}
  .hud{font-size:1.4rem}
  section{scroll-margin-top:60px}
  .kb-row{grid-template-columns:4.5em 1fr auto}
}
@media (max-height:740px){.scene-sticky .xsec{width:min(100%,260px)}}