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*,*::before,*::after{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.62 system-ui,-apple-system,'Segoe UI',Roboto,Arial,sans-serif}a{color:var(--tealdark)}a:hover{text-decoration-thickness:2px}button,input,select{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.55}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #d28417;outline-offset:4px}::selection{background:var(--lime);color:var(--ink)}.skip{position:absolute;left:15px;top:-100px;padding:12px 18px;background:#fff;color:#000;z-index:1000}.skip:focus{top:15px}.container{max-width:1140px;margin:0 auto;padding:0 26px}.site-header{position:relative;z-index:10;background:#fff;border-bottom:1px solid var(--line)}.header-in{min-height:82px;display:flex;gap:24px;align-items:center;justify-content:space-between}.brand{display:flex;gap:11px;align-items:center;color:var(--ink);text-decoration:none}.brand-mark{height:42px;width:42px;display:grid;place-items:center;background:var(--teal);color:#fff;border-radius:13px;font-size:22px;font-weight:850;letter-spacing:-2px}.brand-name{font-size:1.2rem;font-weight:850;letter-spacing:-.04em;line-height:1.1}.brand-sub{display:block;font-size:.7rem;color:var(--muted);letter-spacing:.12em;text-transform:uppercase;font-weight:750;margin-top:4px}.nav-list{list-style:none;margin:0;padding:0;display:flex;gap:7px;align-items:center;flex-wrap:wrap}.nav-list a{display:block;text-decoration:none;font-size:.92rem;font-weight:700;padding:10px 12px;border-radius:12px;color:var(--ink2)}.nav-list a:hover,.nav-list a[aria-current=page]{background:var(--mint);color:var(--tealdark)}.menu-toggle{display:none;background:#fff;border:1px solid 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10px;font-weight:780}.lead{font-size:1.13rem;line-height:1.7;max-width:650px}.hero .lead{color:#dbe7ee;margin-bottom:26px}.actions,.pill-row{display:flex;gap:12px;align-items:center;flex-wrap:wrap}.btn{display:inline-flex;gap:8px;justify-content:center;align-items:center;border:2px solid transparent;border-radius:12px;padding:12px 18px;background:var(--teal);color:#fff;text-decoration:none;font-weight:800;line-height:1.3;min-height:46px}.btn:hover{background:var(--tealdark);color:#fff;text-decoration:none}.btn-light{background:var(--lime);color:var(--ink)}.btn-light:hover{background:#cbea79;color:var(--ink)}.btn-outline{background:transparent;border-color:#aac0c7;color:inherit}.btn-outline:hover{background:#eff5f6;color:var(--ink)}.hero .btn-outline{border-color:#a7c4cc;color:#fff}.hero .btn-outline:hover{background:#fff;color:var(--ink)}.ghost-board{border:1px solid #67919a;border-radius:26px;padding:23px;background:rgba(255,255,255,.08);box-shadow:0 35px 70px 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0}.section-tint{background:#edf3f0}.section-heading{display:flex;justify-content:space-between;align-items:end;gap:20px;margin-bottom:30px}.section-heading p{margin:0;color:var(--muted);max-width:600px}.card-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:19px}.card-grid.two{grid-template-columns:repeat(2,minmax(0,1fr))}.card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:25px;box-shadow:0 9px 27px rgba(14,41,51,.035);min-width:0}.card:hover{box-shadow:var(--shadow)}.card .icon-tile,.icon-tile{display:grid;place-items:center;height:49px;width:49px;border-radius:15px;background:var(--mint);color:var(--tealdark);font-size:1.5rem;margin-bottom:20px}.icon-tile.gold{background:var(--orange);color:#996019}.icon-tile.blue{background:var(--blue);color:#405d9a}.card p{color:var(--ink2);margin:0 0 18px}.text-link{font-weight:800;text-decoration:none}.text-link::after{content:' 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p{color:var(--ink2)}.quote-panel{border-radius:25px;padding:32px;background:#fff;box-shadow:var(--shadow);border:1px solid var(--line)}.quote-panel .big{font-size:2.2rem;font-weight:900;letter-spacing:-.06em;color:var(--teal);line-height:1.2}.resource-list{display:grid;gap:13px}.resource-row{display:grid;grid-template-columns:55px 1fr auto;gap:14px;align-items:center;border:1px solid var(--line);background:#fff;border-radius:16px;padding:17px 20px}.resource-row p{margin:4px 0 0;color:var(--muted);font-size:.9rem}.resource-row .icon-tile{margin:0}.site-footer{background:#17354a;color:#d9e6eb;padding:38px 0 20px}.footer-layout{display:flex;gap:24px;align-items:start;justify-content:space-between}.footer-layout a{color:#effaf6}.footer-links{display:flex;gap:15px;flex-wrap:wrap}.footnote{color:#b8cdd6;border-top:1px solid #4b6c79;margin-top:24px;padding-top:14px;font-size:.8rem}.lesson-layout{display:grid;grid-template-columns:minmax(0,1fr) 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small{font-size:.72rem;color:var(--ink2);font-weight:750}.answer-locked{opacity:.65;pointer-events:none}.smallprint{font-size:.81rem;color:var(--muted)}.notice-list{padding-left:20px}.notice-list li{margin-bottom:12px}.two-up{display:grid;grid-template-columns:1fr 1fr;gap:20px}.inline-formula{font-weight:800;white-space:nowrap;color:var(--ink)}.svg-art{display:block;width:100%;max-width:100%;height:auto}.hero-art-wrap{position:relative}.art-deco{position:absolute;border-radius:50%;background:#dcf3a1;opacity:.7;filter:blur(2px)}.divider{height:1px;background:var(--line);margin:28px 0}.keyboard{font:700 .79rem ui-monospace,monospace;border:1px solid #b5c4cb;background:#fff;padding:3px 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0}.card-grid,.card-grid.two,.unit-grid,.two-up{grid-template-columns:1fr}.section-heading{align-items:start;flex-direction:column}.resource-row{grid-template-columns:40px 1fr}.resource-row>a{grid-column:2}.footer-layout{flex-direction:column}.game-panel{padding:18px}.game-stats{gap:5px}.game-stat{padding:9px 5px}.page-hero{padding:45px 0}.lesson-main h2{margin-top:30px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;animation-duration:.01ms!important;transition-duration:.01ms!important}}
@media print{.site-header,.site-footer,.lesson-aside,.btn,.skip,.game-aside{display:none!important}body{background:#fff;font-size:11pt}.page-hero{background:#fff;padding:20px 0}.section{padding:12px 0}.lesson-layout{display:block}.container{max-width:none}.example,.check{break-inside:avoid}}

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