:root{color-scheme:dark;font-family:-apple-system,BlinkMacSystemFont,'Hiragino Sans','Noto Sans JP',sans-serif;font-size:16px;color:#e9f2f1;background:#101b20;--mint:#8ae2c8;--line:#30464c}*{box-sizing:border-box}body{margin:0}button,a,input{touch-action:manipulation}button{font:inherit;color:inherit;cursor:pointer}a{color:var(--mint);text-underline-offset:4px}button:focus-visible,a:focus-visible{outline:3px solid #f0d184;outline-offset:4px}header{padding:20px max(24px,calc((100% - 1280px)/2));display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);gap:18px}header svg{width:155px;height:42px;display:block}header span{font-size:.875rem;color:#b5c8c9}header b{font-weight:400;border:1px solid #63887e;padding:4px 8px;margin-left:10px;border-radius:4px}main{max-width:1328px;padding:32px 24px 24px;margin:auto}.intro{display:flex;justify-content:space-between;gap:30px;align-items:center;margin-bottom:26px}.eyebrow{letter-spacing:.14em;font-size:.8rem;color:var(--mint);font-weight:600}h1{font-size:clamp(1.85rem,3.2vw,2.8rem);font-weight:600;letter-spacing:.03em;margin:10px 0 14px}h1 em{font-style:normal;color:var(--mint)}p{line-height:1.85}.intro p:not(.eyebrow){color:#adc2c6;font-size:.95rem;margin:0}.progress-box{min-width:220px;font-size:.9rem}.progress-box small{display:block;color:#9cafb5;margin-top:9px}progress{display:block;appearance:none;width:100%;height:5px;margin-top:14px;border:0;border-radius:4px;overflow:hidden}progress::-webkit-progress-bar{background:#30464c}progress::-webkit-progress-value{background:var(--mint)}progress::-moz-progress-bar{background:var(--mint)}.lessons{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin-bottom:20px}.lessons button{text-align:left;padding:16px 20px;border:1px solid var(--line);border-radius:9px;background:#18292e}.lessons button[aria-current]{border-color:var(--mint);background:#1d3b37}.lessons small{display:block;font-size:.8rem;color:#91bdb5;margin-bottom:8px}.lessons strong{font-size:1.08rem;display:block}.lessons span{display:block;font-size:.875rem;color:#acc1c5;margin-top:5px}.classroom{display:grid;grid-template-columns:1.08fr 1fr;gap:26px;align-items:start}.visual{position:sticky;top:16px;border:1px solid var(--line);border-radius:12px;overflow:hidden;background:radial-gradient(ellipse at 45% 30%,#344c56,#17292f 70%)}.view-label{padding:20px 22px 0;display:flex;justify-content:space-between;align-items:center;gap:10px}.view-label span{font-size:.75rem;letter-spacing:.09em;color:#a3c1c6}.view-label strong{font-weight:500;font-size:.95rem}#course-canvas{height:390px;width:100%;position:relative}canvas{display:block;touch-action:none}#model-status{position:absolute;top:160px;left:20px;right:20px;background:#12232fea;padding:16px;border-radius:8px;text-align:center}#model-status[hidden]{display:none}#model-status button{display:block;margin:8px auto}.view-tools{display:flex;gap:6px;justify-content:center;padding:0 12px;flex-wrap:wrap}.view-tools button,.structures button,#restart{background:#102126;border:1px solid #4a686b;border-radius:6px;padding:10px 13px;min-height:44px;font-size:.875rem}.view-tools button:hover,.structures button:hover{background:#254a43}.gesture{font-size:.8rem;color:#b1c5c9;text-align:center;margin:12px 12px 16px}.structures{display:flex;flex-wrap:wrap;gap:7px;padding:0 20px}.structures button[aria-pressed=true]{background:var(--mint);color:#102723;border-color:var(--mint)}.structures button:disabled{opacity:.5;cursor:wait}.legend{margin:14px 20px 6px;font-size:.8rem;color:#b1c6ca}.legend i{display:inline-block;background:var(--mint);width:9px;height:9px;border-radius:50%}.legend span{display:inline-block}.credit{display:block;color:#a8bcc0;font-size:.75rem;margin:10px 20px 20px}.lesson-body{padding:8px 8px 24px}.lesson-body h2{font-size:1.65rem;line-height:1.5;margin:8px 0 12px}.goal{font-size:1rem;color:#b9cecf}.lesson-body h3{font-size:1.05rem;margin:24px 0 6px}.lesson-body p{margin:8px 0;font-size:1rem}.lesson-body dl{display:grid;grid-template-columns:4em 1fr;gap:10px 14px;margin:16px 0;font-size:.95rem;line-height:1.75}.lesson-body dt{color:var(--mint)}.lesson-body dd{margin:0}.observe{border-left:3px solid var(--mint);background:#1b3434;padding:16px 20px;margin:24px 0}.observe strong{color:var(--mint);font-size:.875rem}.observe p{font-size:.95rem}fieldset{border:1px solid var(--line);padding:20px;border-radius:10px;margin:24px 0 18px;min-width:0}legend{font-weight:600;line-height:1.65;padding:0 5px}#answers{display:grid;gap:9px}#answers button{text-align:left;line-height:1.7;background:#182a30;border:1px solid #3e595f;border-radius:6px;padding:12px 14px;font-size:.95rem}#answers button[aria-pressed=true]{border-color:var(--mint)}#answers button.correct{background:#20483d}#answers button.incorrect{background:#483531}#feedback{color:#bdd7d1;font-size:.9rem;margin-bottom:0}button.primary{border:0;background:var(--mint);color:#102a26;border-radius:7px;padding:15px 20px;font-weight:650;min-height:48px}button.primary:disabled{opacity:.45;cursor:default}.lesson-body>.primary{width:100%}#finish{border-top:1px solid #6ea99c;margin-top:28px;padding:32px 0}#finish h2{font-size:2rem;line-height:1.5}.sheet{background:#1a2e33;padding:24px;max-width:800px;border-radius:8px}.sheet ol{padding-left:22px;line-height:2}.sheet p{border-left:2px solid var(--mint);padding-left:18px}.finish-actions{display:flex;align-items:center;flex-wrap:wrap;gap:20px;margin-top:20px}footer{border-top:1px solid var(--line);padding-top:18px;margin-top:25px;color:#9fb5bb;font-size:.8rem;line-height:1.8}footer summary{cursor:pointer;font-size:.875rem}footer li{margin:8px 0}footer a{color:#b6d8d0}[hidden]{display:none!important}@media(max-width:850px){main{padding:22px 16px}.intro{display:block}.progress-box{margin-top:22px;max-width:320px}.classroom{grid-template-columns:1fr}.visual{position:relative;top:0}.lesson-body{padding:0 2px 20px}#course-canvas{height:350px}.lessons{gap:7px}.lessons button{padding:12px 10px}.lessons strong{font-size:.95rem}.lessons span{font-size:.8rem}.view-label{padding:16px 16px 0}.intro p br{display:none}header{padding:14px 16px}header svg{width:125px}.legend,.credit{margin-left:16px;margin-right:16px}.structures{padding:0 16px}}@media(max-width:380px){.lessons span{display:none}header span{font-size:.75rem}header b{margin-left:3px}#course-canvas{height:310px}}@media print{body{background:white;color:black}header,.intro,.lessons,.classroom,.finish-actions,footer details{display:none!important}main{padding:0}#finish{display:block!important;border:0}.sheet{background:white;padding:0}.eyebrow{color:#245a4b}footer{color:#333}}