:root{color-scheme:light;--ink:#17202a;--muted:#5d6874;--line:#d9e1e8;--soft:#f5f7f9;--blue:#1769aa;--teal:#087f6b;--red:#c43b36;--gold:#a96700;--violet:#6346b8}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:#fff;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.62}a{color:var(--blue);text-decoration:none}a:hover{text-decoration:underline}.topbar{position:sticky;top:0;z-index:10;background:rgba(255,255,255,.97);border-bottom:1px solid var(--line)}.nav{max-width:1200px;margin:auto;padding:11px 20px;display:flex;align-items:center;justify-content:space-between;gap:18px}.brand{color:var(--ink);font-weight:800;white-space:nowrap}.navlinks{display:flex;flex-wrap:wrap;justify-content:flex-end;gap:12px}.navlinks a{color:var(--muted);font-size:13px}.navlinks a.active{color:var(--ink);font-weight:800}.page{max-width:1120px;margin:auto;padding:30px 20px 64px}.eyebrow{color:var(--violet);font-size:13px;font-weight:800;text-transform:uppercase;letter-spacing:0;margin-bottom:8px}h1{max-width:21ch;margin:0 0 16px;font-size:52px;line-height:1.08;letter-spacing:0}h2{margin:0 0 14px;font-size:27px;line-height:1.2;letter-spacing:0}h3{margin:0 0 8px;font-size:18px;letter-spacing:0}p{margin:0 0 15px}li{margin:7px 0}.lead{max-width:78ch;color:var(--muted);font-size:18px}.section{margin-top:32px;padding-top:30px;border-top:1px solid var(--line)}.two-col{display:grid;grid-template-columns:minmax(0,1fr) minmax(330px,.95fr);gap:24px;align-items:start}.grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.card{min-width:0;padding:18px;color:var(--ink);background:#fff;border:1px solid var(--line);border-radius:8px}.card p{color:var(--muted)}.num{width:31px;height:31px;margin-bottom:10px;display:grid;place-items:center;color:#fff;background:var(--violet);border-radius:50%;font-weight:800}.activity{margin:16px 0 20px;padding:15px 17px;background:#f2f7fc;border:1px solid #c8daf0;border-left:5px solid var(--blue);border-radius:8px}.activity h3{color:var(--blue)}.activity .prompt{margin:0;color:var(--ink);font-weight:750}.formula{margin:15px 0;padding:17px;overflow-x:auto;background:#f7fbff;border:1px solid var(--line);border-radius:8px;font-size:17px}.formula mjx-container{margin:4px 0!important}.intuition{margin:14px 0;padding:13px 16px;color:#105046;background:#edf9f6;border-left:4px solid var(--teal);border-radius:0 8px 8px 0}.note{margin:14px 0;padding:13px 16px;color:#402b7a;background:#f5f2fc;border-left:4px solid var(--violet);border-radius:0 8px 8px 0}.warning{color:#694100;background:#fff7e8;border-left-color:var(--gold)}.visual{padding:16px;background:#fbfcfd;border:1px solid var(--line);border-radius:8px}.plot{width:100%;min-height:270px;display:block;aspect-ratio:4/3}.plot-wide{width:100%;min-height:280px;display:block;aspect-ratio:16/7}.caption,.small{color:var(--muted);font-size:13px}.axis{stroke:#63707c;stroke-width:1.5}.axis-label{fill:var(--muted);font-size:12px}.plot-title{fill:var(--ink);font-size:15px;font-weight:750}.legend{display:flex;flex-wrap:wrap;gap:14px;margin-top:9px;color:var(--muted);font-size:13px}.swatch{width:11px;height:11px;display:inline-block;margin-right:5px;border-radius:50%}.table-wrap{width:100%;overflow-x:auto}table{width:100%;margin:16px 0;border-collapse:collapse;font-size:14px}th,td{padding:10px;text-align:left;vertical-align:top;border:1px solid var(--line)}th{background:var(--soft)}.numeric{text-align:right;font-variant-numeric:tabular-nums}.steps{padding-left:0;counter-reset:step}.steps li{position:relative;padding-left:42px;margin:13px 0;list-style:none}.steps li::before{counter-increment:step;content:counter(step);position:absolute;left:0;top:0;width:28px;height:28px;display:grid;place-items:center;color:#fff;background:var(--violet);border-radius:50%;font-weight:800}.pager{display:flex;justify-content:space-between;gap:12px;margin-top:38px;padding-top:18px;border-top:1px solid var(--line)}.button{min-height:40px;padding:8px 14px;display:inline-flex;align-items:center;justify-content:center;color:var(--ink);background:#fff;border:1px solid var(--line);border-radius:8px;font-weight:750}.button.primary{color:#fff;background:var(--violet);border-color:var(--violet)}code{padding:1px 4px;background:#eef1f4;border:1px solid var(--line);border-radius:4px}@media(max-width:850px){.two-col,.grid{grid-template-columns:1fr}.nav{align-items:flex-start;flex-direction:column}.navlinks{justify-content:flex-start}}@media(max-width:520px){h1{font-size:36px}.page{padding-inline:14px}.pager{flex-direction:column}.button{width:100%}}@media print{.topbar,.pager{display:none}.section{break-inside:avoid}}