:root{--ink:#19191b;--paper:#faf9f7;--orange:#e95100;--line:#d9d6d0;--muted:#686562;--blue:#24566f}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.55 Arial,sans-serif}header,main,footer{max-width:1160px;margin:auto;padding:24px}header{display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line);gap:20px}.brand{font-size:26px;font-weight:800;text-decoration:none;color:var(--ink)}.brand span{color:var(--orange)}nav{display:flex;flex-wrap:wrap;gap:20px}a{color:var(--blue)}nav a{color:var(--ink);font-size:14px}nav a[aria-current]{color:var(--orange);font-weight:bold}.hero{padding:40px 0 24px}.eyebrow{text-transform:uppercase;font:12px/1.5 Consolas,monospace;letter-spacing:.1em;color:var(--orange)}h1{font:600 clamp(38px,6vw,68px)/1.08 Georgia,serif;letter-spacing:-.035em;margin:16px 0}h2{font:600 27px/1.25 Georgia,serif;margin:0 0 12px}.hero>p:last-child{color:var(--muted)}button,select,input{font:inherit}button{cursor:pointer;border:1px solid var(--line);background:#fff;border-radius:8px;padding:11px 16px;min-height:44px;color:var(--ink)}button:hover{border-color:var(--orange)}button:disabled{opacity:.5;cursor:default}.primary{background:var(--orange);color:white;border-color:var(--orange);font-weight:600}label{display:block;font-size:14px;font-weight:600}select,input[type=text],#answer{display:block;padding:11px 12px;border:1px solid var(--line);border-radius:6px;background:white;width:100%;min-height:46px;margin-top:6px}select{max-width:100%}.setup{display:flex;align-items:end;gap:16px;padding:20px;background:#eeeae4;border-radius:12px}.setup label:first-child{flex:1}.lab{display:grid;grid-template-columns:240px minmax(0,1fr);gap:26px;margin:24px 0 40px}.navigator{padding-top:20px}.navigator h2{font-size:22px}#problemNav{display:grid;grid-template-columns:repeat(5,1fr);gap:6px;margin:16px 0}#problemNav button{padding:6px;min-width:0}#problemNav button.active{outline:2px solid var(--orange)}#problemNav button.correct{background:#e5f0e8;color:#215637}#problemNav button.missed{border-bottom:3px solid #b44622}#problemNav button.review{background:#e7eff4}.quiet,.syntax{color:var(--muted);font-size:13px}.paper{background:white;border:1px solid var(--line);border-top:4px solid var(--orange);border-radius:10px;padding:30px;box-shadow:0 12px 30px #19191b08}.problem-head{display:flex;justify-content:space-between;gap:12px;align-items:center;font:13px Consolas,monospace}.problem-head p{margin:0}#ruleLabel{color:var(--muted)}.instruction{font-size:14px;color:var(--muted);margin-top:28px}.expression{font:600 clamp(24px,4vw,38px)/1.4 Consolas,monospace;overflow-wrap:anywhere;margin:18px 0 30px}.actions,.paging{display:flex;gap:12px;flex-wrap:wrap;margin:16px 0}.paging{justify-content:space-between;border-top:1px solid var(--line);padding-top:20px;margin-top:28px}.syntax{margin:8px 0}#feedback{padding:0;color:var(--blue);font-weight:600}#hints{padding-left:22px}#hints li{padding:8px 0}details{border-top:1px solid var(--line);padding-top:16px}summary{cursor:pointer;font-weight:600;min-height:44px}#explanation p{margin:12px 0}.teacher{display:grid;grid-template-columns:1fr 1fr;gap:50px;padding:32px;background:#e7eff3;border-radius:12px}.teacher-tools{display:flex;flex-direction:column;align-items:start;justify-content:center;gap:16px}.check{display:flex;align-items:center;gap:10px}.check input{width:20px;height:20px}.about{max-width:800px;padding:36px 0;font-size:14px;color:var(--muted)}.about h2{font-size:22px;color:var(--ink)}footer{display:flex;gap:24px;flex-wrap:wrap;border-top:1px solid var(--line);font-size:14px}#worksheet{display:none}:focus-visible{outline:3px solid var(--blue);outline-offset:3px}@media(max-width:720px){header{align-items:start;flex-direction:column}nav{gap:14px}.lab{grid-template-columns:1fr}.navigator{padding:0}#problemNav{grid-template-columns:repeat(10,1fr)}#problemNav button{font-size:13px}.navigator .quiet{display:none}.setup{flex-wrap:wrap}.setup label:first-child{flex-basis:100%}.teacher{grid-template-columns:1fr;gap:16px}.paper{padding:20px}.problem-head{flex-wrap:wrap}main,header,footer{padding:18px}}@media(max-width:400px){#problemNav{grid-template-columns:repeat(5,1fr)}}@media print{body{background:white;font-size:12pt}header,footer,main>*{display:none!important}main{padding:0;max-width:none}main>#worksheet{display:block!important}#worksheet h1{font:24pt Georgia,serif}#worksheet ol{padding-left:28px}.worksheet-question{min-height:120px;break-inside:avoid;font:14pt Consolas,monospace}.answer-key{break-before:page}.answer-key li{break-inside:avoid;margin:18px 0}body>div,body>button{display:none!important}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important}}
