:root{color-scheme:light;--ink:#17344f;--muted:#587088;--blue:#245fa5;--line:#d9e2eb;--paper:#fff;--green:#33715c;font-family:Inter,'Segoe UI',sans-serif;background:#fafbfc;color:var(--ink);font-size:15px}
*{box-sizing:border-box}body{margin:0}a{color:var(--blue);text-underline-offset:4px}button,input,textarea{font:inherit}button,.button{min-height:40px;border:1px solid #bdcddd;border-radius:5px;padding:8px 14px;background:#fff;color:var(--blue);cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:8px}button:hover,.button:hover{background:#edf4fb}button:active{background:#e1ebf7}button:disabled{opacity:.45;cursor:default}a:focus-visible,button:focus-visible,textarea:focus-visible,input:focus-visible{outline:3px solid #e0a44a;outline-offset:3px}.skip{position:fixed;top:-100px;left:10px;background:white;padding:14px;z-index:10}.skip:focus{top:8px}
.site-header{height:72px;background:white;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 32px;gap:20px}.brand{font:800 27px/1 Outfit,'Segoe UI',sans-serif;letter-spacing:-1px;text-decoration:none;color:#0b2545}.brand span{color:var(--blue)}.header-tools{display:flex;gap:20px;align-items:center;font-size:13px}.preview-notice{padding:9px 24px;background:#f6f0e5;color:#715a36;text-align:center;font-size:12px;border-bottom:1px solid #eadfc9}
.course-shell{display:grid;grid-template-columns:280px minmax(0,1fr);min-height:calc(100vh - 106px)}aside{background:white;border-right:1px solid var(--line);padding:24px 15px;max-height:calc(100vh - 106px);overflow:auto;position:sticky;top:0}.directory-home{display:block;padding:10px;text-decoration:none;font-weight:650;margin-bottom:12px}.directory-topic{border-top:1px solid var(--line)}.directory-topic summary{padding:14px 8px;cursor:pointer;line-height:1.5;font-size:13px;font-weight:600}.directory-topic a{display:block;padding:9px 12px 9px 22px;font-size:12px;line-height:1.5;text-decoration:none;border-left:2px solid transparent}.directory-topic a[aria-current=page]{background:#edf4fc;border-left-color:var(--blue);font-weight:650}.directory-topic a:hover{background:#f4f7fb}.directory-topic .overview-link{font-weight:650}
main{width:100%;max-width:1180px;margin:0 auto;padding:32px clamp(18px,4vw,58px) 64px;min-width:0}.breadcrumb{font-size:12px;color:var(--muted);margin:0 0 24px}.eyebrow{color:var(--muted);font-size:11px;text-transform:uppercase;letter-spacing:1.3px;margin:0 0 10px}h1,h2,h3{font-family:Outfit,'Segoe UI',sans-serif}h1{font-size:clamp(28px,3vw,42px);line-height:1.15;letter-spacing:-.7px;margin:0 0 16px}h2{font-size:23px;margin:0 0 16px;letter-spacing:-.3px}h3{font-size:18px;margin:0 0 12px}p{line-height:1.7}.lead{max-width:740px;color:var(--muted);font-size:16px;margin:0 0 24px}.badges{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:24px}.badge{font-size:11px;background:#f0f4f8;border:1px solid var(--line);padding:5px 9px;border-radius:4px;line-height:1.5}.mode-tabs{display:flex;gap:8px;margin:24px 0;flex-wrap:wrap}.mode-tabs a{display:block;border-bottom:2px solid transparent;padding:10px 15px;text-decoration:none;font-size:13px}.mode-tabs a[aria-current=page]{border-bottom-color:var(--blue);color:var(--ink);font-weight:700;background:#eef4fb}.panel{background:white;border:1px solid var(--line);border-radius:8px;padding:clamp(18px,2.5vw,30px);margin:20px 0}.topic-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin:28px 0}.topic-card{background:white;border:1px solid var(--line);border-radius:7px;padding:22px;text-decoration:none;color:var(--ink)}.topic-card:hover{border-color:#88a7c8;background:#f8fbff}.topic-card h2{font-size:19px;line-height:1.4;margin:8px 0 12px}.topic-card p{font-size:12px;color:var(--muted);margin:8px 0}.topic-number{font-size:12px;color:var(--blue);font-weight:650}.mode-progress{display:flex;gap:12px;flex-wrap:wrap;font-size:10px;color:var(--muted);margin-top:18px}.progress-track{height:3px;background:#e8eef5;margin-top:16px}.progress-track span{display:block;height:100%;background:var(--blue)}
.concept-map{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin:18px 0}.concept-node{position:relative;border:1px solid var(--line);padding:16px;border-radius:5px;background:#f7faff}.concept-node+.concept-node:before{content:'→';position:absolute;left:-12px;top:45%;color:var(--blue);background:white}.concept-node strong{font-size:14px;display:block;line-height:1.4}.concept-node p{font-size:12px;color:var(--muted);margin:8px 0 0}.unit-list{display:grid;gap:10px}.unit-link{display:flex;align-items:center;justify-content:space-between;gap:14px;padding:17px 20px;border:1px solid var(--line);border-radius:5px;background:white;text-decoration:none;color:var(--ink);line-height:1.5}.unit-link small{color:var(--muted);display:block;font-size:11px;margin-top:5px}.unit-link:hover{border-color:#88a7c8}.topic-figure{width:100%;height:auto;max-height:260px;display:block;background:#f8fbff;border:1px solid var(--line);border-radius:6px;margin:20px 0}.topic-figure text{font-family:'Segoe UI',sans-serif;fill:var(--ink)}
.step-controls{display:flex;gap:9px;margin:16px 0;flex-wrap:wrap}.step-controls button[aria-pressed=true]{color:white;background:var(--blue);border-color:var(--blue)}.learning-step{font-size:18px;line-height:1.8;max-width:800px;min-height:130px}.step-label{font-size:11px;color:var(--blue);text-transform:uppercase;letter-spacing:1px}.why{border-top:1px solid var(--line);padding-top:15px;margin-top:22px}.why summary{font-weight:650;cursor:pointer;font-size:13px}.why p{color:var(--muted);font-size:14px}.working{padding-left:24px;line-height:1.9}.working li{margin:12px 0}.pitfall{border-left:3px solid #b47b2d;background:#fcf8ef;padding:15px 18px;font-size:14px;line-height:1.7}.practical-label{color:var(--green)}.quiz-options{display:grid;gap:10px;margin:24px 0}.quiz-options label{padding:14px;border:1px solid var(--line);border-radius:5px;display:flex;gap:12px;align-items:flex-start;line-height:1.6;cursor:pointer}.quiz-options input{margin-top:5px;accent-color:var(--blue)}.feedback{margin:18px 0;padding:18px;background:#edf6f1;border-left:3px solid var(--green);line-height:1.7}.feedback.needs-work{background:#fcf7ed;border-color:#b47b2d}.actions{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin-top:20px}.small{font-size:12px;color:var(--muted);line-height:1.7}.recall-card{padding:25px;background:#f7faff;border:1px solid var(--line);border-radius:7px;margin:16px 0}.recall-card summary{font-size:18px;line-height:1.6;cursor:pointer}.recall-card p{border-top:1px solid var(--line);padding-top:15px}.recall-card[open]{background:white}textarea{width:100%;min-height:150px;padding:15px;border:1px solid #bdcddd;border-radius:5px;color:var(--ink);line-height:1.7;resize:vertical}details.source-notes{font-size:12px;color:var(--muted);line-height:1.8;margin-top:30px}.source-notes summary{cursor:pointer}.course-shell.is-collapsed{grid-template-columns:1fr}.course-shell.is-collapsed aside{display:none}.mode-done{font-size:12px;color:var(--green)}[hidden]{display:none!important}
@media(max-width:1000px){.course-shell{grid-template-columns:245px minmax(0,1fr)}main{padding:28px 24px 50px}.concept-map{grid-template-columns:1fr}.concept-node+.concept-node:before{display:none}}
@media(max-width:760px){.site-header{height:64px;padding:0 16px}.brand{font-size:23px}.header-tools{gap:10px}.header-tools>span{font-size:10px;max-width:100px;line-height:1.5}.course-shell{display:block}aside{position:relative;max-height:none;border-right:0;border-bottom:1px solid var(--line)}main{padding:26px 18px 44px}.topic-grid{grid-template-columns:1fr}.preview-notice{font-size:10px;padding:8px 12px}.learning-step{min-height:0;font-size:16px}.mode-tabs{gap:0}.mode-tabs a{padding:9px 11px}.concept-map{grid-template-columns:1fr}.topic-figure{max-height:none}.badge{font-size:10px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important}}
.learning-step{min-height:90px}