@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Manrope:wght@400;500;600;700;800&display=swap');
:root{--blue:#2848ea;--ink:#151e36;--muted:#637089;--paper:#f5f4f0;--orange:#ff6940;--line:#dce0e8;--green:#16724e;--red:#ae352e;font-family:'DM Sans',Arial,sans-serif;color:var(--ink);background:var(--paper);color-scheme:light}*{box-sizing:border-box}body{margin:0}button,a{-webkit-tap-highlight-color:transparent}button{font:inherit;cursor:pointer}button:disabled{cursor:default}a{color:inherit}button:focus-visible,a:focus-visible{outline:3px solid var(--orange);outline-offset:5px}button{transition:background .18s,transform .18s}button:hover:not(:disabled){transform:translateY(-2px)}.topbar{height:100px;display:flex;justify-content:space-between;align-items:center;padding:0 4vw;background:#fff;border-bottom:1px solid var(--line)}.brand{display:flex;gap:14px;align-items:center;text-decoration:none;font-family:Manrope,Arial,sans-serif;font-weight:800;font-size:29px;letter-spacing:-1px}.brand-mark{width:50px;height:50px;display:grid;place-items:center;background:var(--blue);color:#fff;border-radius:13px;font-size:36px}.brand-sub{display:block;font-family:'DM Sans',Arial,sans-serif;letter-spacing:1.7px;font-size:10px;margin-top:3px;color:var(--muted);font-weight:600}.source-button{padding:10px 0;border:0;border-bottom:1px solid #b9c1d1;background:none;font-size:14px;color:var(--muted)}.workspace{max-width:1600px;margin:auto;display:grid;grid-template-columns:260px minmax(0,1fr);padding:42px 4vw 52px;gap:48px}.contents{padding-top:10px}.tiny-label{font-size:12px;font-weight:700;letter-spacing:1.8px;color:var(--blue)}.course-label h2{font:800 30px/1.2 Manrope,Arial,sans-serif;letter-spacing:-1px;margin:16px 0}.course-label p{font-size:16px;line-height:1.6;color:var(--muted);margin:0 0 28px}.contents nav{display:grid;gap:5px}.chapter-link{display:flex;gap:12px;align-items:center;border:0;background:none;width:100%;padding:12px;text-align:left;font-size:14px;color:var(--muted);border-radius:10px}.chapter-link span{flex:0 0 27px;height:27px;display:grid;place-items:center;font-size:12px;font-weight:700;border:1px solid #cad1df;border-radius:50%}.chapter-link.active{background:var(--blue);color:#fff;font-weight:700}.chapter-link.active span{border-color:#7287f4;background:#fff;color:var(--blue)}.chapter-link.done:not(.active) span{border-color:#b1cdc0;color:var(--green);background:#e8f3eb}.sidebar-note{display:flex;align-items:center;gap:12px;margin:30px 12px;color:var(--muted)}.sidebar-note>span{font-weight:800;border:1px solid #cad1df;border-radius:50%;width:30px;height:30px;text-align:center;line-height:30px}.sidebar-note p{font-size:14px;line-height:1.5}.learning-area{min-width:0}.course-top{display:flex;justify-content:space-between;gap:10px;align-items:center;font-size:12px;letter-spacing:1.6px;font-weight:700;color:var(--muted);margin:8px 0 14px}.course-top>span:last-child{color:var(--blue)}.progress{display:flex;gap:5px;margin-bottom:26px}.progress span{height:5px;flex:1;background:#dbe0ed;border-radius:5px}.progress span.complete{background:var(--blue)}.lesson-card{background:#fff;border:1px solid var(--line);border-radius:25px;overflow:hidden;box-shadow:0 12px 50px #172c5706;animation:enter .3s ease}.lesson-main{display:grid;grid-template-columns:1fr 1fr;min-height:460px}.lesson-copy{padding:42px 35px 26px}.lesson-tag{font-size:12px;font-weight:700;letter-spacing:1.6px;color:var(--blue);display:flex;align-items:center;gap:10px}.lesson-tag:before{content:'';width:22px;height:3px;border-radius:3px;background:var(--orange)}h1{font:800 clamp(32px,3.05vw,48px)/1.12 Manrope,Arial,sans-serif;letter-spacing:-1.6px;margin:19px 0 21px;max-width:600px}.lead{font-size:18px;line-height:1.6;color:var(--muted);margin:0}.rule-list{list-style:none;margin:25px 0 0;padding:0;display:grid;gap:16px}.rule-list li{display:flex;align-items:flex-start;gap:12px;font-size:16px;line-height:1.55}.rule-list li:before{content:'✓';color:var(--blue);font-size:16px;font-weight:700;line-height:1.7;flex:0 0 18px}.lesson-art{background:#ecedfa;position:relative;display:flex;align-items:center;justify-content:center;min-width:0;margin:18px 18px 18px 0;border-radius:16px;overflow:hidden}.lesson-art img{display:block;width:100%;height:auto;max-height:440px;object-fit:contain}.art-caption{position:absolute;bottom:17px;left:17px;font-size:12px;font-weight:700;letter-spacing:1px;background:#ffffffdf;padding:9px 13px;border-radius:7px}.why{display:grid;grid-template-columns:110px 1fr;gap:15px;padding:22px 35px;background:#f0f3ff;border-top:1px solid #e2e7fb}.why strong{color:var(--blue);font-size:14px}.why p{margin:0;color:#3f4e74;font-size:15px;line-height:1.6}.lesson-bottom{display:flex;justify-content:space-between;gap:20px;align-items:center;padding:22px 35px;border-top:1px solid var(--line)}.secondary{border:1px solid var(--line);border-radius:10px;padding:13px 18px;background:#fff;color:var(--ink);font-weight:600;font-size:14px}.secondary:disabled{opacity:.35}.primary{background:var(--blue);color:#fff;border:0;padding:15px 23px;border-radius:10px;font-weight:700;font-size:15px;display:flex;justify-content:space-between;align-items:center;gap:30px;box-shadow:0 5px 12px #2848ea19}.primary:hover:not(:disabled){background:#1d37bf}.primary:disabled{opacity:.4}.lesson-bottom .page-note{font-size:12px;color:var(--muted)}.safety-note{display:flex;gap:10px;font-size:13px;line-height:1.6;color:var(--muted);margin:19px 4px 0}.safety-note span{color:var(--orange);font-weight:800}.quiz-intro{display:grid;grid-template-columns:1.1fr .9fr;background:var(--blue);border-radius:25px;overflow:hidden;color:#fff;padding:48px;align-items:center;gap:30px;animation:enter .3s ease}.quiz-intro .tiny-label{color:#c4cffc}.quiz-intro h1{font-size:48px}.quiz-intro p{color:#d1dafa;font-size:18px;line-height:1.6}.quiz-intro img{width:100%;border-radius:18px}.quiz-intro .primary{background:#ffbb77;color:var(--ink);margin-top:30px}.quiz-intro .secondary{background:transparent;color:#fff;border-color:#758bee;margin-top:16px}.quiz-meta{display:flex;gap:20px;font-size:14px;font-weight:700;margin-top:25px;color:#c4cffc}.quiz-card{background:#fff;border:1px solid var(--line);border-radius:25px;padding:38px clamp(24px,5vw,70px);min-height:540px;animation:enter .3s ease}.quiz-card h1{font-size:clamp(28px,3.2vw,44px);max-width:820px;line-height:1.2;margin-bottom:28px}.options{display:grid;gap:12px}.option{display:flex;gap:16px;align-items:center;padding:19px 21px;text-align:left;border:1px solid #dce0e8;border-radius:13px;background:#fff;font-size:17px;line-height:1.5;color:var(--ink)}.option .letter{display:grid;place-items:center;flex:0 0 32px;height:32px;background:#f0f2f7;border-radius:8px;font-size:14px;font-weight:700}.option.selected{border-color:var(--blue);background:#eef1ff;box-shadow:0 0 0 1px var(--blue)}.option.selected .letter{background:var(--blue);color:#fff}.option.correct{border-color:var(--green);background:#eaf5ef}.option.correct .letter{background:var(--green);color:#fff}.option.incorrect{border-color:var(--red);background:#fff0ed}.option.incorrect .letter{background:var(--red);color:#fff}.option:disabled{color:var(--ink);opacity:1}.feedback{padding:20px 22px;background:#f0f3ff;border-radius:12px;margin:22px 0 0;line-height:1.6;font-size:16px}.feedback strong{display:block;margin-bottom:6px}.feedback p{margin:0;color:#465673}.feedback.is-correct{background:#eaf5ef}.feedback.is-correct strong{color:var(--green)}.quiz-actions{display:flex;justify-content:space-between;align-items:center;gap:20px;margin-top:28px}.text-link{border:0;background:none;font-size:14px;color:var(--muted);text-decoration:underline;text-underline-offset:4px}.result{background:#fff;border:1px solid var(--line);border-radius:25px;padding:42px;animation:enter .3s ease}.result-top{display:grid;grid-template-columns:1fr 190px;gap:35px;align-items:center}.result h1{font-size:44px}.result p{font-size:17px;line-height:1.7;color:var(--muted)}.score-circle{aspect-ratio:1;display:grid;place-content:center;border-radius:50%;background:var(--blue);color:#fff;text-align:center;border:10px solid #e9edff}.score-circle strong{font:800 46px/1.1 Manrope,Arial,sans-serif;letter-spacing:-2px}.score-circle span{font-size:14px;margin-top:6px}.result-note{background:#fff4e4;padding:20px 24px;border-radius:12px;margin:28px 0;font-size:16px;line-height:1.7}.review-heading{font:800 22px/1.3 Manrope,Arial,sans-serif;margin:26px 0 15px}.review-items{display:grid;gap:10px}.review-item{background:#f3f5fa;border-radius:12px;padding:18px 21px;display:flex;align-items:center;justify-content:space-between;gap:18px}.review-item p{margin:0;font-size:15px}.review-item button{white-space:nowrap;border:0;background:none;color:var(--blue);font-size:14px;font-weight:700;text-decoration:underline;text-underline-offset:4px}.result .quiz-actions{flex-wrap:wrap}footer{max-width:1600px;margin:auto;padding:25px 4vw;display:flex;justify-content:space-between;gap:20px;border-top:1px solid var(--line);font-size:12px;color:var(--muted)}footer a{text-decoration:none;font-weight:700}footer button{border:0;background:none;font-size:12px;color:inherit}dialog{width:min(700px,calc(100% - 30px));max-height:90vh;border:0;border-radius:20px;background:#fff;padding:42px;color:var(--ink);box-shadow:0 30px 100px #00114740}dialog::backdrop{background:#13234e99;backdrop-filter:blur(5px)}dialog h2{font:800 30px/1.2 Manrope,Arial,sans-serif;letter-spacing:-1px}dialog p{font-size:16px;line-height:1.7;color:var(--muted)}.close-dialog{position:absolute;right:16px;top:12px;border:0;background:none;font-size:30px;color:var(--muted)}.sources{display:grid;gap:15px;padding:20px 0;border-block:1px solid var(--line)}.sources a{font-size:14px;line-height:1.6;color:var(--blue);text-underline-offset:4px}dialog .fine{font-size:13px}.noscript{text-align:center;padding:30px}@keyframes enter{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
@media(min-width:1500px){.lesson-copy{padding:50px}.lesson-main{min-height:520px}.lesson-art img{max-height:520px}}
@media(max-width:1150px){.workspace{grid-template-columns:205px 1fr;gap:28px}.lesson-main{grid-template-columns:1fr}.lesson-art{margin:0 25px 25px;height:290px}.lesson-art img{width:auto;max-width:100%;height:100%}.course-label h2{font-size:26px}.lesson-copy{padding:32px}.quiz-intro{padding:35px;grid-template-columns:1fr}.quiz-intro img{max-height:280px;object-fit:contain}.quiz-intro h1{font-size:40px}}
@media(max-width:760px){.topbar{height:82px;padding:0 22px}.brand{font-size:23px}.brand-mark{width:42px;height:42px;font-size:30px}.brand-sub{font-size:8px;letter-spacing:1.1px}.source-button{font-size:12px;max-width:90px;text-align:right;line-height:1.6}.workspace{grid-template-columns:1fr;padding:22px 18px 36px;gap:20px}.course-label,.sidebar-note{display:none}.contents{padding:0;min-width:0}.contents nav{display:flex;gap:6px;overflow-x:auto;padding:4px 0 10px;scrollbar-width:thin}.chapter-link{width:auto;padding:8px;gap:7px;font-size:13px;flex-shrink:0}.chapter-link span{flex-basis:22px;width:22px;height:22px;font-size:11px}.chapter-link .chapter-title{display:none}.chapter-link.active .chapter-title{display:block}.course-top{font-size:10px;letter-spacing:1.2px}.progress{margin-bottom:20px}.lesson-card{border-radius:18px}.lesson-copy{padding:27px 24px 22px}h1{font-size:34px;letter-spacing:-1.2px}.lead{font-size:17px}.rule-list{gap:14px}.rule-list li{font-size:16px}.lesson-art{height:245px;margin:0 14px 18px}.art-caption{left:12px;bottom:12px;font-size:10px}.why{grid-template-columns:1fr;gap:8px;padding:20px 24px}.lesson-bottom{padding:20px 24px}.lesson-bottom .page-note{display:none}.primary{font-size:14px;padding:14px 19px;gap:20px}.secondary{font-size:13px;padding:13px 15px}.quiz-intro{border-radius:18px;padding:30px 26px;gap:22px}.quiz-intro h1{font-size:38px}.quiz-intro p{font-size:17px}.quiz-card{padding:28px 23px;border-radius:18px;min-height:0}.quiz-card h1{font-size:29px;letter-spacing:-1px}.option{padding:16px 14px;font-size:16px;gap:12px}.quiz-actions{gap:15px}.feedback{padding:17px;font-size:15px}.result{padding:28px 24px;border-radius:18px}.result-top{grid-template-columns:1fr 110px;gap:15px}.result h1{font-size:30px;letter-spacing:-1px}.score-circle{border-width:6px}.score-circle strong{font-size:31px}.score-circle span{font-size:11px}.result p{font-size:16px}.review-item{display:block}.review-item button{margin-top:10px;padding:0}.result-note{padding:17px;font-size:15px}footer{padding:22px;flex-wrap:wrap}footer>span{display:none}dialog{padding:32px 25px}dialog h2{font-size:27px}}
/* Shorter copy and a quieter learning surface. */
.workspace{gap:44px;padding-top:48px}
.contents{padding-top:62px}
.course-top{font-size:14px;font-weight:500;letter-spacing:0}
.lesson-main{min-height:390px;align-items:center}
.lesson-copy{padding:42px 36px}
.lesson-copy h1{margin:0 0 32px;font-size:clamp(30px,3vw,43px);letter-spacing:-1.3px}
.rule-list{margin:0;gap:22px}
.lesson-art{align-self:stretch;background:transparent}
.lesson-art img{border-radius:12px}
details.why{display:block;background:transparent;padding:18px 35px;border-top:1px solid var(--line)}
.why summary{cursor:pointer;color:var(--muted);font-size:14px;width:fit-content}
.why summary:focus-visible{outline:3px solid var(--orange);outline-offset:5px}
.why p{max-width:720px;margin:12px 0 0}
.lesson-bottom{padding:22px 35px}
.result-note{background:#f3f5fa;color:var(--muted);font-size:14px;padding:16px 20px}
@media(max-width:1150px){.lesson-main{min-height:0}.lesson-art{height:auto;aspect-ratio:3/2;max-height:340px}.lesson-art img{height:100%;width:100%;object-fit:contain}}
@media(max-width:760px){.workspace{padding-top:20px;gap:16px}.contents{padding-top:0}.lesson-copy{padding:30px 24px}.lesson-copy h1{font-size:30px;margin-bottom:26px}.rule-list{gap:20px}.lesson-art{aspect-ratio:3/2;height:auto;max-height:none}.lesson-bottom{padding:20px 24px}details.why{padding:18px 24px}.course-top{font-size:13px;letter-spacing:0}.result-top{grid-template-columns:1fr 110px}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}