:root{--ink:#20344b;--muted:#5b6c7d;--blue:#326cdb;--line:#dbe5eb;--paper:#fff;--wash:#f4f7f8;--accent:#d3913f}
body{background:var(--wash);color:var(--ink);font-size:17px;line-height:1.7}
header,main,footer{max-width:1180px}
a{color:#2455a4;text-underline-offset:4px}
button,input,select{font:inherit}
button,a,summary,input,select{touch-action:manipulation}
button:focus-visible,a:focus-visible,summary:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #ad6a12;outline-offset:4px}
button{min-height:46px;cursor:pointer;border:1px solid #acbfd0;color:var(--ink);background:white;padding:10px 16px;border-radius:9px;line-height:1.4}
button:hover{border-color:var(--blue);background:#f0f5ff}
button[aria-pressed=true]{background:#244f8a;color:white;border-color:#244f8a}
.topline{display:flex;align-items:center;justify-content:space-between;gap:20px;font-size:14px;margin-bottom:38px}
.brand{font-weight:800;text-decoration:none;font-size:19px;color:var(--ink)}
.draft-label{color:#7c541d;background:#fff1d6;border:1px solid #e3c999;border-radius:5px;padding:3px 10px;white-space:nowrap}
.eyebrow{font-size:13px;letter-spacing:.12em;text-transform:uppercase;color:#496984;font-weight:800}
.hero{display:grid;grid-template-columns:1.05fr 1fr;gap:40px;align-items:center;padding:12px 0 38px}
.hero h1{font-size:clamp(34px,5vw,57px);letter-spacing:-.045em;line-height:1.06;margin:14px 0 20px;max-width:660px}
.hero p{font-size:19px;color:var(--muted);max-width:550px}
.hero-art{background:#e9eff4;border-radius:24px;padding:20px;transform:rotate(-1deg);border:1px solid #d0dde8}
.hero-art svg{display:block;width:100%;height:auto;background:#fff;border-radius:15px}
.hero-art .art-note{font-size:14px;text-align:center;font-weight:600;color:#445d71;margin:10px 0 0}
.primary-link{display:inline-block;background:#255fba;color:#fff;text-decoration:none;border-radius:8px;padding:11px 21px;font-weight:700}
.quiet-link{display:inline-block;margin-left:15px;font-size:15px}
.section-heading{display:flex;align-items:baseline;gap:25px;justify-content:space-between;margin:16px 0 25px}
.section-heading h2{font-size:30px;letter-spacing:-.025em;margin:0}
.section-heading p{color:var(--muted);font-size:15px}
.lesson-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px}
.lesson-card{border:1px solid var(--line);background:white;border-radius:16px;overflow:hidden;display:flex;flex-direction:column;box-shadow:0 7px 16px #2a466507}
.lesson-card>a{color:inherit;text-decoration:none;height:100%;display:flex;flex-direction:column}
.lesson-card>a:hover h3{color:var(--blue)}
.lesson-card svg{height:255px;width:100%;display:block;padding:12px;background:#f0f5fa;border-bottom:1px solid var(--line)}
.lesson-card .card-copy{padding:22px 26px;flex:1}
.lesson-card h3{font-size:25px;line-height:1.25;letter-spacing:-.02em;margin:12px 0}
.lesson-card p{font-size:16px;margin:0 0 16px;color:var(--muted)}
.lesson-card .open-lesson{font-size:15px;color:#2455a4;font-weight:700}
.subject-tag{font-size:12px;text-transform:uppercase;letter-spacing:.07em;font-weight:800;color:#3c617d}
.lesson-shell{max-width:970px}
.lesson-header{max-width:970px;padding-bottom:8px}
.lesson-header h1{font-size:clamp(32px,5vw,51px);letter-spacing:-.04em;line-height:1.1;max-width:780px;margin:14px 0}
.lesson-header .lead{font-size:20px;color:var(--muted);max-width:790px}
.lesson-meta{font-size:14px;color:var(--muted);margin-top:20px}
.lesson-route{display:flex;flex-wrap:wrap;gap:10px;margin:24px 0 8px;font-size:14px}
.lesson-route span{background:#e9eff4;padding:5px 10px;border-radius:5px}
.learning-step{display:grid;grid-template-columns:48px minmax(0,1fr);gap:18px;padding:30px 0 34px;border-bottom:1px solid var(--line)}
.step-number{height:42px;width:42px;display:grid;place-items:center;background:#dfeaf5;border-radius:50%;font-size:16px;font-weight:800;color:#375f83;margin-top:5px}
.step-content h2{font-size:30px;letter-spacing:-.025em;margin:5px 0 20px;line-height:1.2}
.step-content h3{font-size:20px;margin:0 0 12px;line-height:1.4}
.step-content>p{max-width:780px}
.teaching-figure{margin:24px 0 26px;background:white;border:1px solid #d7e3ec;border-radius:14px;overflow:hidden}
.teaching-figure svg{display:block;width:100%;height:auto;max-height:440px;padding:20px 22px;background:#fcfdff}
.teaching-figure figcaption{border-top:1px solid #dce6ee;background:#edf3f8;font-size:16px;line-height:1.65;padding:19px 24px;color:#324c64}
.concept-pair,.comparison,.flow-comparison{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:22px 0}
.concept-pair p,.comparison>div,.flow-comparison>div{padding:20px;background:#e9f0f5;border-radius:10px;margin:0}
.concept-pair strong{color:#244f8a;font-size:19px}
.explorer{padding:25px;background:#eaf3f1;border:1px solid #bad7cd;border-radius:14px;margin:24px 0}
.explorer h3{color:#265445}
.explorer [data-model] svg{display:block;width:100%;height:auto;background:#fff;border-radius:9px;margin:20px 0 0}
.controls{display:flex;gap:20px;align-items:flex-start;flex-wrap:wrap;margin-top:20px}
.controls label{display:flex;flex-direction:column;gap:10px;font-size:14px;font-weight:700;flex:1;min-width:150px}
.controls select{padding:7px 10px;border-radius:6px;max-width:160px;background:white;border:1px solid #91b3a5}
.controls input[type=range]{width:100%;min-height:35px;accent-color:#255fba}
.controls output{font-size:17px;color:#244f8a}
.live-feedback{background:white;border-left:4px solid #4b8d70;padding:17px 19px;margin:20px 0 0!important;border-radius:5px;min-height:70px}
.choice-buttons{display:flex;flex-wrap:wrap;gap:10px;margin:18px 0}
.choice-buttons button{flex:1 1 160px;text-align:left}
.checkpoint{border-left:4px solid #ce964a;background:#fff3df;border-radius:8px;padding:23px;margin:24px 0 0}
.checkpoint summary{font-size:16px;color:#775420}
.checkpoint details{border-top:1px solid #e4cda9;margin-top:16px;padding-top:16px}
.reading-excerpt,.source-paper{background:#fffdf8;border:1px solid #dacbb3;padding:25px;border-radius:4px;box-shadow:4px 5px 0 #ded5c680;margin:22px 0}
.reading-excerpt p{font-family:Georgia,serif;font-size:21px;line-height:1.85;margin-bottom:0}
.guide-browser{display:grid;grid-template-columns:1fr 1.4fr;gap:15px;margin-top:20px}
.guide-menu{display:flex;flex-direction:column;gap:9px}
.guide-page{background:#fffef8;padding:22px;border:1px solid #d3c8b4;border-radius:5px;min-height:260px}
.guide-page h4,.source-paper h4{font-size:19px;line-height:1.4;margin:0 0 16px}
.pathway{display:flex;align-items:center;flex-wrap:wrap;gap:9px;margin:20px 0}
.pathway span{background:white;border:1px solid #adc5b9;padding:10px 14px;border-radius:6px;font-size:16px}
.pathway b{color:#3a7862;font-size:24px}
.flow-comparison{grid-template-columns:1fr}
.energy-stage{background:white;border-radius:10px;padding:15px;text-align:center}
.energy-stage svg{display:block;width:100%;max-height:220px}
.energy-stage strong{display:block;font-size:24px;color:#255546;padding:10px}
.branch-stage{background:white;border:1px solid #c2d7cd;padding:24px;border-radius:9px;min-height:175px}
.branch-stage strong{font-size:24px;color:#275b48}
.fiction-label{font-size:15px;background:#f7eddb;border-left:4px solid #b48245;padding:12px 18px}
.narrative-builder{background:white;border:1px solid var(--line);padding:24px;border-radius:12px}
.narrative-builder mark{display:inline-block;color:#35536d;background:#e8eff5;padding:0 6px;font-size:14px;font-weight:700}
.full-text{margin-top:35px!important}
.full-text summary{font-size:20px}
.full-text .detail-section{padding-top:20px;margin-top:20px;border-top:1px solid var(--line)}
.next-lesson{display:flex;justify-content:space-between;gap:20px;align-items:center;margin:34px 0 45px;padding:24px;background:#e7eef7;border-radius:12px}
.review-note{font-size:14px;color:var(--muted);margin-top:35px;padding-top:18px;border-top:1px solid var(--line)}
.audit-links{margin:40px 0;padding:30px;background:white;border-radius:14px;border:1px solid var(--line)}
.question-visual{max-width:650px;margin:20px auto;background:#f4f8fc;border-radius:10px}
.question-visual svg{width:100%;height:auto;display:block}
@media(max-width:740px){.hero{grid-template-columns:1fr;gap:24px}.hero-art{max-width:580px}.topline{gap:10px;margin-bottom:28px}.brand{font-size:16px}.draft-label{font-size:11px}.section-heading{display:block}.lesson-grid{grid-template-columns:1fr}.lesson-card svg{height:220px}.lesson-header .lead{font-size:18px}.learning-step{grid-template-columns:1fr;gap:12px}.step-number{height:35px;width:35px}.step-content h2{font-size:27px}.teaching-figure svg{padding:8px 5px}.teaching-figure figcaption{padding:16px;font-size:15px}.explorer{padding:18px 15px}.concept-pair,.comparison{grid-template-columns:1fr}.guide-browser{grid-template-columns:1fr}.guide-menu{display:grid;grid-template-columns:1fr 1fr}.guide-menu button{font-size:14px;padding:10px}.next-lesson{flex-direction:column;align-items:stretch}.quiet-link{margin:14px 0 0}.reading-excerpt{padding:19px}.reading-excerpt p{font-size:19px}.lesson-card .card-copy{padding:20px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important}}