:root{--bg:#fbfaf7;--bg-elev:#fff;--bg-code:#f4f1ea;--bg-viz:#fbf8f2;--ink:#1f1d1a;--ink-soft:#4a4742;--ink-mute:#8a857d;--rule:#e6e1d6;--accent:#b14a2e;--accent-soft:#e6c7bd;--link:#8e3a22;--highlight:#fff3d6;--pos:#fde0d2;--pos-stroke:#d8a48a;--neg:#d5e6dc;--neg-stroke:#9ec3ae;--zero:#f0eee5;--serif:"Iowan Old Style","Charter",Georgia,"Hoefler Text",Cambria,serif;--sans:-apple-system,BlinkMacSystemFont,"Segoe UI",Inter,Roboto,sans-serif;--mono:"JetBrains Mono","SF Mono","Fira Code",Menlo,Consolas,monospace}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--serif);font-size:18px;line-height:1.62;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}main{max-width:760px;margin:0 auto;padding:24px 28px 80px}p{margin:0 0 18px 0}strong{color:var(--ink)}em{font-style:italic;color:var(--ink)}h1,h2,h3,h4{font-family:var(--serif);color:var(--ink);line-height:1.2;margin:28px 0 12px 0}h1{font-size:38px;letter-spacing:-0.01em;margin-top:6px}h2{font-size:22px;font-weight:700;text-transform:uppercase;letter-spacing:.05em;border-top:1px solid var(--rule);padding-top:24px;margin-top:36px}h3{font-size:18px;font-weight:700}a{color:var(--link);text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:2px}a:hover{color:var(--accent)}code{font-family:var(--mono);font-size:.85em;background:var(--bg-code);padding:1px 5px;border-radius:3px}pre{background:var(--bg-code);border-radius:6px;padding:14px 16px;overflow-x:auto;margin:14px 0}pre code{background:transparent;padding:0;font-size:14px}pre.equation{background:var(--bg-elev);border-left:3px solid var(--accent);border-radius:0 4px 4px 0}pre.equation code{font-size:15px}pre.nb-output{background:transparent;border:1px dashed var(--rule);margin-top:-8px;color:var(--ink-mute)}pre.nb-output code{background:transparent;font-size:13px;color:var(--ink-mute)}pre.nb-output::before{content:"Output";display:block;font-family:var(--sans);font-size:10px;font-weight:700;text-transform:uppercase;letter-spacing:.06em;color:var(--ink-mute);margin-bottom:4px}main code[class*="language-"],main pre[class*="language-"]{font-size:.85em}table{font-family:var(--sans);font-size:14px;border-collapse:collapse;margin:8px 0 18px 0}th,td{padding:6px 12px}thead th{text-align:left;border-bottom:1px solid var(--rule);font-weight:600}tbody td{border-bottom:1px solid var(--rule)}tbody tr:last-child td{border-bottom:0}ul,ol{margin:0 0 18px 0;padding-left:22px}li{margin-bottom:6px}aside.toc{position:fixed;left:24px;top:24px;width:220px;max-height:calc(100vh - 48px);overflow-y:auto;font-family:var(--sans);font-size:13px;color:var(--ink-soft);z-index:50}aside.toc .toc-title{font-family:var(--sans);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.1em;color:var(--ink-mute);padding-bottom:8px;border-bottom:1px solid var(--rule);margin-bottom:8px}aside.toc ul{list-style:none;padding:0;margin:0}aside.toc li{margin-bottom:4px}aside.toc a{color:var(--ink-soft);text-decoration:none;display:block;padding:4px 8px;border-radius:4px;border-left:2px solid transparent}aside.toc a:hover{background:var(--bg-elev)}aside.toc a.active{color:var(--ink);border-left-color:var(--accent);background:var(--bg-elev)}aside.toc .toc-foot{margin-top:14px;padding-top:10px;border-top:1px solid var(--rule);font-size:11px}aside.toc li.toc-sub{margin-bottom:2px}aside.toc li.toc-sub a{padding-left:20px;font-size:12px}@media(max-width:1180px){aside.toc{display:none}}.hero{margin-bottom:14px}.eyebrow{font-family:var(--sans);font-size:11px;text-transform:uppercase;letter-spacing:.12em;color:var(--ink-mute);margin-bottom:6px}.subtitle{font-family:var(--serif);font-style:italic;font-size:22px;color:var(--ink-soft);margin:6px 0 14px 0}.byline{font-family:var(--sans);font-size:14px;color:var(--ink-mute)}.lede{font-size:19px;line-height:1.6;margin-bottom:18px}.cite{font-family:var(--sans);font-size:13px;color:var(--ink-mute);margin:18px 0 24px 0;padding:12px 16px;background:var(--bg-elev);border-radius:6px}.cite a{color:var(--ink-soft)}.viz{background:var(--bg-viz);border:1px solid var(--rule);border-radius:10px;padding:18px 20px;margin:20px 0 24px 0}.viz-title{font-family:var(--sans);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.08em;color:var(--ink-mute);margin-bottom:8px}.viz-title code{font-size:11px;padding:0 4px}.viz-title::before{content:"● ";color:var(--accent)}.viz-description{font-family:var(--serif);font-size:14px;color:var(--ink-soft);margin-bottom:14px;line-height:1.55}.viz-caption{margin-top:10px;font-family:var(--serif);font-size:13px;color:var(--ink-mute);font-style:italic}.callout{margin:18px 0;padding:14px 18px;border-radius:8px;border:1px solid var(--rule)}.callout.insight{background:#fffaef;border-left:3px solid var(--accent)}.callout.note{background:var(--bg-elev);border-left:3px solid #cfdbf2}.callout .label{display:block;font-family:var(--sans);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.08em;color:var(--ink-mute);margin-bottom:8px}.callout p{margin-bottom:8px;font-size:15px}.callout p:last-child{margin-bottom:0}.callout.tps{background:#f0f8f2;border-left:3px solid #4a9d6a}.tps-steps{list-style:none;margin:0;padding:0;display:grid;gap:7px}.tps-steps li{font-size:15px}.tps-steps .tps-phase{display:inline-block;font-family:var(--sans);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.07em;color:#2f7a4d;margin-right:8px}.tps-reveal{margin-top:10px}.tps-reveal>summary{cursor:pointer;display:inline-block;font-family:var(--sans);font-size:12px;font-weight:700;color:#2f7a4d;background:#e3f1e8;border:1px solid #b6d8c2;border-radius:5px;padding:5px 11px;list-style:none;-webkit-user-select:none;user-select:none}.tps-reveal>summary::-webkit-details-marker{display:none}.tps-reveal>summary::marker{content:""}.tps-reveal[open]>summary{color:var(--ink-mute);background:transparent;border-color:transparent;padding:0;font-weight:400;font-size:11px}.tps-reveal[open]>summary::before{content:"✓ "}.tps-reveal .tps-steps{margin-top:10px}.callout.optview{background:#f5f2fa;border-left:3px solid #7a6aa8}.callout.optview .label{color:#5d4f85}.optview-rows{list-style:none;margin:0;padding:0;display:grid;gap:8px}.optview-rows li{display:grid;grid-template-columns:104px 1fr;gap:10px;align-items:baseline;font-size:15px}.optview-key{font-family:var(--sans);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.07em;color:#5d4f85}.optview-how{display:inline-block;font-family:var(--sans);font-size:11px;font-weight:700;letter-spacing:.04em;border-radius:4px;padding:1px 7px;margin-right:7px;white-space:nowrap}.optview-how.how-formula{background:var(--pos);color:#8a4a26}.optview-how.how-grid{background:var(--zero);color:#6b6558}.optview-how.how-iterative{background:var(--neg);color:#2f6b4c}@media(max-width:620px){.optview-rows li{grid-template-columns:1fr;gap:2px}}.exercise{margin:18px 0;padding:14px 18px;background:#fffdf5;border:1px solid #ead990;border-left:3px solid #c89b1f;border-radius:6px}.exercise .ex-label{font-family:var(--sans);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.08em;color:#8a6f1a;margin-bottom:8px}.exercise details{margin-top:8px;font-size:14px;color:var(--ink-soft)}.exercise summary{cursor:pointer;font-family:var(--sans);font-size:13px;color:var(--ink-mute)}.btn{font-family:var(--sans);font-size:13px;padding:6px 14px;background:var(--bg-elev);color:var(--ink);border:1px solid var(--rule);border-radius:5px;cursor:pointer;transition:background .08s,border-color .08s,opacity .08s}.btn:hover{background:#f0eee5;border-color:var(--ink-mute)}.btn:disabled{opacity:.5;cursor:not-allowed}.btn.primary{background:var(--accent);color:white;border-color:var(--accent)}.btn.primary:hover{filter:brightness(1.08)}.chat-downloads{display:flex;align-items:center;gap:10px;margin-top:14px;padding-top:12px;border-top:1px solid var(--rule);flex-wrap:wrap}.chat-downloads-label{font-family:var(--sans);font-size:12px;color:var(--ink-mute);letter-spacing:.03em}.chat-dl-btn{font-family:var(--mono);font-size:12px;padding:5px 11px;border:1px solid var(--rule);background:var(--bg-elev);color:var(--ink-soft);border-radius:14px;cursor:pointer;text-decoration:none;transition:background .08s,border-color .08s,color .08s}.chat-dl-btn:hover{background:#fff3d6;border-color:var(--accent);color:var(--ink)}footer{margin-top:60px;padding-top:18px;border-top:1px solid var(--rule);font-family:var(--sans);font-size:13px;color:var(--ink-mute)}.present-controls{position:fixed;top:16px;left:16px;z-index:1000;display:flex;gap:6px;align-items:center}.present-toggle{display:inline-flex;align-items:center;gap:6px;padding:6px 12px;background:var(--bg-elev);border:1px solid var(--rule);border-radius:18px;font-family:var(--sans);font-size:12px;color:var(--ink-soft);cursor:pointer;box-shadow:0 1px 4px rgba(0,0,0,0.05);transition:background .1s,color .1s,border-color .1s}.present-toggle:hover{background:#fff3d6;color:var(--ink);border-color:var(--accent)}.present-toggle:active{transform:translateY(1px)}.present-toggle .present-icon{font-size:16px;line-height:1}body.presentation-mode #present-toggle{background:var(--accent);color:white;border-color:var(--accent)}.present-toggle.present-nav{display:none;padding:6px 10px;min-width:36px;justify-content:center}body.presentation-mode .present-toggle.present-nav{display:inline-flex}.lab-index-link{text-decoration:none;color:var(--ink-mute);background:var(--bg)}.lab-index-link:hover{background:var(--bg-elev);color:var(--ink);border-color:var(--accent-soft)}.lab-index-link .present-icon{font-size:15px}body.presentation-mode .lab-index-link{background:var(--bg);color:var(--ink-mute);border-color:var(--rule)}.lab-prev-next{display:grid;grid-template-columns:1fr 1fr 1fr;gap:12px;margin:56px 0 24px;padding-top:24px;border-top:1px solid var(--rule)}@media(max-width:760px){.lab-prev-next{grid-template-columns:1fr}}.lab-prev-next-card{display:flex;flex-direction:column;gap:4px;padding:14px 16px;background:var(--bg-elev);border:1px solid var(--rule);border-radius:6px;text-decoration:none;color:var(--ink);transition:border-color 120ms,transform 120ms,background 120ms;min-height:88px}.lab-prev-next-card:hover{border-color:var(--accent);background:white;transform:translateY(-1px)}.lab-prev-next-card.lab-prev-next-next{text-align:right;align-items:flex-end}.lab-prev-next-card.lab-prev-next-home{text-align:center;align-items:center;background:#fff8e8;border-color:#e7d9a8}.lab-prev-next-card.lab-prev-next-home:hover{background:#fff0c8;border-color:var(--accent)}.lab-prev-next-dir{font-family:var(--sans);font-size:11px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--accent)}.lab-prev-next-num{font-family:var(--mono);font-size:12px;font-weight:600;color:var(--ink-mute)}.lab-prev-next-title{font-family:var(--serif);font-size:16px;font-weight:600;line-height:1.25;color:var(--ink)}.lab-prev-next-empty{visibility:hidden}body.presentation-mode .lab-prev-next{display:none}body.presentation-mode aside.toc,body.presentation-mode footer,body.presentation-mode .hero .byline,body.presentation-mode .lede,body.presentation-mode .cite,body.presentation-mode p:not(.keep-in-present):not(.viz-description):not(.viz-caption){display:none}body.presentation-mode main{max-width:1040px;font-size:22px;padding:70px 40px 60px}body.presentation-mode h1{font-size:56px}body.presentation-mode h2{font-size:30px;margin-top:60px;padding-top:30px}body.presentation-mode h3{font-size:22px}body.presentation-mode pre code,body.presentation-mode pre{font-size:17px}body.presentation-mode pre.equation code{font-size:20px}body.presentation-mode .viz{margin:32px 0 40px 0;padding:24px 28px}body.presentation-mode .viz-description{font-size:17px}body.presentation-mode .callout{font-size:18px;padding:22px 28px}body.presentation-mode table{font-size:17px}.gloss{cursor:help;border-bottom:1px dotted var(--accent);padding-bottom:.5px;transition:background .12s,color .12s}.gloss:hover,.gloss:focus,.gloss.active{background:var(--accent-soft);color:var(--ink);outline:0;border-radius:2px}.gloss code{background:transparent;padding:0}.glossary-hint{font-family:var(--sans);font-size:13.5px;line-height:1.55;color:var(--ink-soft);background:var(--bg-elev);padding:12px 16px;border-radius:6px;border-left:3px solid var(--rule);margin:18px 0 10px 0}.glossary-hint code{background:var(--bg-code);font-size:.92em;padding:1px 5px;border-radius:3px}.glossary-hint .gloss-demo{border-bottom:1px dotted var(--accent);padding-bottom:.5px}.glossary-panel{position:relative;background:#fffaef;border:1px solid var(--rule);border-left:3px solid var(--accent);border-radius:0 6px 6px 0;padding:14px 44px 12px 18px;margin:0 0 22px 0;animation:gloss-fade-in .18s ease-out}.glossary-panel[hidden]{display:none}@keyframes gloss-fade-in{from{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:translateY(0)}}.glossary-panel-title{font-family:var(--sans);font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.08em;color:var(--ink-mute);margin-bottom:8px}.glossary-content{font-family:var(--serif);font-size:15px;line-height:1.55;color:var(--ink)}.glossary-content p{margin:0 0 8px 0}.glossary-content p:last-child{margin-bottom:0}.glossary-content code{font-family:var(--mono);font-size:.92em;background:var(--bg-code);padding:1px 5px;border-radius:3px}.glossary-close{position:absolute;top:8px;right:10px;background:0;border:0;cursor:pointer;font-family:var(--sans);font-size:20px;line-height:1;color:var(--ink-mute);padding:2px 6px;border-radius:4px}.glossary-close:hover{color:var(--accent);background:var(--bg-elev)}body.presentation-mode .glossary-content{font-size:18px}body.presentation-mode .glossary-panel{padding:18px 50px 16px 22px}