:root{--ink:#142b3d;--muted:#50687a;--line:#ccdce4;--paper:#f6f9fb;--accent:#007c71;--blue:#155bb3;--mono:ui-monospace,SFMono-Regular,Consolas,monospace;color-scheme:light}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:28px}body{margin:0;font:17px/1.7 Arial,Helvetica,sans-serif;color:var(--ink);background:var(--paper)}a{color:var(--blue);text-underline-offset:4px}a:hover{color:var(--accent)}button,input,select{font:inherit}button,summary,a,input,select{touch-action:manipulation}a:focus-visible,button:focus-visible,summary:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #cf7222;outline-offset:4px}button{cursor:pointer}p{margin:0 0 20px}h1,h2,h3{margin:0 0 18px;line-height:1.15}h1{font-size:clamp(2.8rem,7vw,5.6rem);font-weight:600;letter-spacing:-.065em;max-width:960px}h2{font-size:clamp(1.9rem,3.8vw,2.8rem);font-weight:600;letter-spacing:-.04em}h3{font-size:1.3rem;letter-spacing:-.02em}strong,b{font-weight:700}.wrap{max-width:1300px;padding:0 36px;margin:auto}.top{background:#fff;border-bottom:1px solid var(--line)}.top .wrap{display:flex;justify-content:space-between;gap:20px;align-items:center;padding-top:22px;padding-bottom:22px}.brand{font-weight:800;letter-spacing:.09em;text-decoration:none;color:var(--ink)}.top nav{display:flex;flex-wrap:wrap;gap:12px 24px;font-size:14px}.top nav a{text-decoration:none}.hero{padding:48px 0 30px}.eyebrow,.deck{font:13px/1.55 var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--accent);margin-bottom:18px}.lead{font-size:21px;max-width:820px;line-height:1.55}.byline{font-size:14px;color:var(--muted)}.doors{display:grid;grid-template-columns:1.2fr 1fr;gap:28px;margin:26px 0 30px}.door{border-top:3px solid var(--accent);padding-top:19px}.door p{font-size:16px;max-width:670px}.links{display:flex;flex-wrap:wrap;gap:12px}.button{display:inline-block;border:1px solid var(--line);padding:10px 15px;background:#fff;color:var(--ink);border-radius:4px;text-decoration:none;font-size:14px}.button.primary{background:var(--ink);color:white;border-color:var(--ink)}.layout{display:grid;grid-template-columns:240px minmax(0,1fr);gap:52px}.toc{align-self:start;position:sticky;top:20px;max-height:calc(100vh - 40px);overflow-y:auto;padding:0 12px 30px 0}.toc h2{font:13px var(--mono);margin:12px 0}.toc a{display:block;font-size:14px;line-height:1.45;padding:7px 0;text-decoration:none;color:var(--muted)}.toc a:hover,.toc a.active{color:var(--accent)}.toc details{border:0;padding:0}.toc summary{font-size:15px;padding:10px 0;cursor:pointer}.chapter{padding:38px 0 35px;border-top:1px solid var(--line)}.chapter .deck{margin-bottom:15px}article{min-width:0}article>section{scroll-margin-top:24px}.principle,.task,.capstone{padding:24px 26px;margin:25px 0;background:#e9f2f3;border-left:3px solid var(--accent)}.principle p,.task p,.capstone p:last-child{margin-bottom:0}.task{background:#fff;border-left-color:#93b8cb}.task strong{display:block;margin-bottom:9px;font:13px var(--mono);color:var(--accent)}.formula{font:18px/1.75 var(--mono);overflow-x:auto;padding:20px 24px;margin:25px 0;background:#102b40;color:#effaff;border-radius:4px;white-space:normal}.table-wrap{overflow-x:auto;margin:25px 0}table{border-collapse:collapse;width:100%;font-size:15px;text-align:left}th,td{padding:13px 14px;border-bottom:1px solid var(--line);vertical-align:top}th{background:#e9f0f5;font-size:14px;color:var(--muted)}.reference,.caption{font-size:14px;color:var(--muted)}.case{padding:24px 0;border-bottom:1px solid var(--line)}.tag{display:block;font:13px/1.6 var(--mono);color:var(--accent);margin-bottom:12px}.inline-image figure,.gallery figure{margin:24px 0}.inline-image img{width:100%;height:auto;border:1px solid var(--line);display:block}.inline-image figcaption{font-size:14px;margin-top:12px;color:var(--muted)}.gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px}.gallery figure{margin:0 0 20px}.gallery img{width:100%;aspect-ratio:1.4;object-fit:contain;background:#e9edef;border:1px solid var(--line);display:block}.gallery h3{font-size:18px;margin:14px 0 8px}.gallery p{font-size:14px;margin-bottom:6px}.gallery .caption{font:12px var(--mono)}.source{padding:17px 0;border-bottom:1px solid var(--line)}.source h3{font-size:18px;margin-bottom:9px}.source p{font-size:15px;margin-bottom:6px}.document{padding:20px;border:1px solid var(--line);background:white;margin-bottom:15px}.document h3{font-size:19px}.document p{font-size:15px;margin-bottom:14px}.document small{font-size:13px;color:var(--muted)}.lab{border:1px solid #a6c9c5;background:#fff;padding:25px;margin:25px 0}.lab h3{font-size:22px}.controls{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin:20px 0}.field{display:block;font-size:14px;color:var(--muted)}.field input,.field select{display:block;width:100%;margin-top:7px;padding:9px 10px;border:1px solid #91aebd;border-radius:3px;color:var(--ink);background:white;min-height:43px}.results{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin:18px 0}.result{padding:16px;background:#eaf4f2;font-size:14px}.result strong{display:block;font-size:25px;line-height:1.3;letter-spacing:-.03em;margin:5px 0}.lab-note{font-size:14px;color:var(--muted)}.good{color:#006256}.bad{color:#9a2a24}.chart{width:100%;height:auto;display:block}.chart text,.diagram text{font-family:Arial,sans-serif;font-size:15px}.diagram svg{display:block;width:100%;height:auto;margin:26px 0}.question{border:1px solid var(--line);padding:22px;background:white;margin:20px 0}.question legend{font-weight:bold;padding:0 6px;font-size:17px}.question label{display:block;padding:8px 0;font-size:16px}.question input{margin-right:10px;accent-color:var(--accent)}.feedback{font-size:15px;margin:12px 0 0}.quizscore{font-size:20px;font-weight:700;margin:20px 0}details{border-top:1px solid var(--line);padding:14px 0}summary{cursor:pointer}pre{font:14px/1.6 var(--mono);background:#e7f0f5;padding:20px;overflow:auto;white-space:pre-wrap;overflow-wrap:anywhere}.footer{border-top:1px solid var(--line);padding:28px 0 40px;margin-top:30px;font-size:14px;color:var(--muted)}.skip{position:absolute;top:-100px;left:20px}.skip:focus{top:12px;background:white;padding:8px;z-index:10}.error{color:#9a2a24}.archivenote{font-size:15px;padding:20px;background:#eef1f6;margin:22px 0}.section-links{display:flex;gap:20px;flex-wrap:wrap;margin-top:25px}.section-links a{font-size:14px}.muted{color:var(--muted)}@media(max-width:1000px){.layout{grid-template-columns:190px minmax(0,1fr);gap:30px}.wrap{padding:0 24px}}@media(max-width:760px){body{font-size:16px}.wrap{padding:0 20px}.top .wrap{align-items:flex-start;flex-direction:column;gap:12px}.top nav{font-size:14px}.hero{padding-top:32px}.lead{font-size:19px}.doors{grid-template-columns:1fr;gap:18px}.layout{display:block}.toc{position:static;max-height:none;border-top:1px solid var(--line);padding-bottom:22px}.toc a{font-size:15px;padding:9px 0}.toc details:not([open]){padding:0}.chapter{padding:30px 0}.controls,.results,.gallery{grid-template-columns:1fr}.lab{padding:18px}.formula{font-size:15px;padding:17px}.task,.principle,.capstone{padding:20px}.table-wrap table{min-width:580px}h1{letter-spacing:-.05em}.gallery img{aspect-ratio:auto}.diagram{overflow-x:auto}.diagram svg{min-width:620px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}@media print{body{background:#fff;color:#000;font-size:11pt}.wrap{padding:0;max-width:none}.layout{display:block}.top,.toc,.doors,.quiz-actions,.controls,.section-links,.skip{display:none}.hero{padding:0}.chapter{break-before:page;padding-top:15px}.chapter:first-child{break-before:auto}h1{font-size:36pt}h2{font-size:24pt}.formula{background:white;color:black;border:1px solid #aaa}.task,.principle,.capstone{background:#f5f5f5}.gallery{grid-template-columns:1fr 1fr}.gallery figure{break-inside:avoid}.lab{break-inside:avoid}.source,.document,.question{break-inside:avoid}a{color:inherit}.diagram svg{min-width:0}.table-wrap{overflow:visible}.table-wrap table{min-width:0}}