:root{
  --navy-950:#070d18;--navy-900:#0b1220;--navy-800:#111c30;--blue-600:#2563eb;--blue-500:#3b82f6;
  --slate-950:#0f172a;--slate-700:#334155;--slate-600:#475569;--slate-500:#64748b;--slate-300:#cbd5e1;
  --slate-200:#e2e8f0;--slate-100:#f1f5f9;--page:#f8fafc;--white:#fff;--border:rgba(15,23,42,.10);
  --shadow:0 20px 55px rgba(15,23,42,.11);--radius:22px;--max:1200px;
  --accent:#2563eb;--accent-soft:#eff6ff;--accent-ink:#1d4ed8;
}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--slate-950);background:var(--page);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.6;text-rendering:optimizeLegibility}
body::before{content:"";position:fixed;inset:0;z-index:-2;pointer-events:none;background:radial-gradient(circle at 12% 8%,rgba(56,189,248,.08),transparent 28rem),radial-gradient(circle at 90% 24%,rgba(37,99,235,.07),transparent 30rem),linear-gradient(#f8fafc,#f8fafc)}
a{color:inherit}img{display:block;max-width:100%}button{font:inherit}.container,.wrap{width:min(var(--max),calc(100% - 40px));margin:0 auto}
.skip-link{position:fixed;left:12px;top:12px;z-index:1000;transform:translateY(-160%);padding:10px 14px;border-radius:10px;color:#fff;background:var(--navy-900);text-decoration:none}.skip-link:focus{transform:translateY(0)}
.site-header{position:sticky;top:0;z-index:50;border-bottom:1px solid rgba(148,163,184,.18);background:rgba(248,250,252,.9);backdrop-filter:blur(18px)}
.nav-shell{min-height:74px;display:flex;align-items:center;justify-content:space-between;gap:22px}.brand{display:inline-flex;align-items:center;gap:12px;text-decoration:none}.brand img{width:42px;height:42px}.brand-copy{display:grid;line-height:1.1}.brand-copy strong{font-size:15px;letter-spacing:.04em}.brand-copy span{margin-top:5px;color:var(--slate-500);font-size:10.5px;font-weight:850;letter-spacing:.1em;text-transform:uppercase}
.nav-links{display:flex;align-items:center;gap:3px}.nav-links a{border-radius:10px;padding:9px 11px;color:var(--slate-600);font-size:13px;font-weight:750;text-decoration:none}.nav-links a:hover,.nav-links a:focus-visible,.nav-links a.active{color:var(--slate-950);background:var(--slate-100);outline:none}.nav-links .nav-cta{margin-left:8px;color:#fff;background:var(--navy-900)}.nav-links .nav-cta:hover,.nav-links .nav-cta:focus-visible{color:#fff;background:var(--blue-600)}
.nav-toggle{display:none;width:44px;height:44px;border:1px solid var(--border);border-radius:12px;color:var(--slate-950);background:#fff;cursor:pointer}
.library-hero{padding:78px 0 62px;border-bottom:1px solid var(--border);background:linear-gradient(135deg,rgba(255,255,255,.88),rgba(239,246,255,.8))}.library-hero-grid{display:grid;grid-template-columns:minmax(0,1fr) 260px;gap:54px;align-items:end}.eyebrow{display:inline-flex;align-items:center;gap:9px;margin:0 0 15px;color:var(--accent);font-size:12px;font-weight:900;letter-spacing:.14em;text-transform:uppercase}.eyebrow::before{content:"";width:30px;height:2px;background:currentColor}
h1,h2,h3,p{margin-top:0}.library-hero h1{max-width:760px;margin:0 0 16px;font-size:clamp(2.75rem,5.2vw,4.7rem);line-height:.97;letter-spacing:-.052em}.library-lead{max-width:720px;margin:0 0 26px;color:var(--slate-600);font-size:1.06rem}.hero-actions{display:flex;flex-wrap:wrap;gap:10px}
.btn{min-height:46px;display:inline-flex;align-items:center;justify-content:center;gap:8px;border:1px solid transparent;border-radius:12px;padding:11px 16px;font-weight:850;text-decoration:none}.btn.primary{color:#fff;background:var(--blue-600)}.btn.primary:hover{background:var(--blue-500)}.btn.ghost-dark{border-color:var(--slate-300);background:#fff}.btn:hover,.btn:focus-visible{outline:none;transform:translateY(-1px);box-shadow:0 10px 24px rgba(15,23,42,.12)}
.library-switcher{display:grid;gap:7px;border:1px solid var(--border);border-radius:18px;padding:14px;background:rgba(255,255,255,.82);box-shadow:0 12px 30px rgba(15,23,42,.05)}.library-switcher>span{padding:4px 7px;color:var(--slate-500);font-size:10px;font-weight:900;letter-spacing:.13em;text-transform:uppercase}.library-switcher a{border-radius:10px;padding:9px 11px;color:var(--slate-700);background:#fff;text-decoration:none;font-size:13px;font-weight:800}.library-switcher a:hover,.library-switcher a[aria-current="page"]{color:#fff;background:var(--navy-900)}
#catalog{padding:72px 0 86px}.section-head{max-width:720px;margin:0 0 26px}.section-head h2{margin:0 0 9px;font-size:clamp(2rem,3.8vw,3.2rem);line-height:1.02;letter-spacing:-.04em}.section-head p{margin:0;color:var(--slate-600);font-size:1rem}.filters{display:flex;gap:8px;flex-wrap:wrap;margin:0 0 20px}.filter-button{border:1px solid var(--slate-200);border-radius:999px;padding:8px 13px;color:var(--slate-600);background:#fff;font-size:12px;font-weight:850;cursor:pointer}.filter-button:hover,.filter-button:focus-visible,.filter-button.active{border-color:var(--accent);color:#fff;background:var(--accent);outline:none}.library-summary{margin:-4px 0 24px;color:var(--slate-500);font-size:13px}
.catalog-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.catalog-card{min-height:100%;display:grid;grid-template-rows:auto auto 1fr auto;gap:11px;overflow:hidden;border:1px solid var(--border);border-radius:20px;padding:0 19px 19px;color:inherit;background:#fff;box-shadow:0 10px 28px rgba(15,23,42,.055);text-decoration:none;transition:transform .2s ease,box-shadow .2s ease,border-color .2s ease;opacity:1!important;visibility:visible!important;transform:none!important}.catalog-card:hover,.catalog-card:focus-visible{transform:translateY(-4px)!important;border-color:rgba(37,99,235,.28);box-shadow:var(--shadow);outline:none}.catalog-card[hidden]{display:none!important}
.catalog-thumb{position:relative;min-height:154px;margin:0 -19px 2px;overflow:hidden;isolation:isolate;background:#111827}.catalog-thumb::before,.catalog-thumb::after{content:"";position:absolute;z-index:0}.catalog-thumb b{position:absolute;z-index:2;left:18px;bottom:15px;border:1px solid rgba(255,255,255,.23);border-radius:999px;padding:7px 10px;color:#fff;background:rgba(15,23,42,.34);font-size:10px;font-weight:900;letter-spacing:.08em;text-transform:uppercase;backdrop-filter:blur(8px)}
.catalog-thumb.app-art{display:grid;place-items:center;background:linear-gradient(145deg,#111827,#172554)}.catalog-thumb.app-art img{width:96px;height:96px;border-radius:23px;object-fit:cover;filter:drop-shadow(0 12px 22px rgba(0,0,0,.28))}.catalog-thumb.app-art b{left:18px}.memory-art{background:radial-gradient(circle at 72% 28%,#a78bfa,transparent 25%),radial-gradient(circle at 25% 72%,#22d3ee,transparent 25%),linear-gradient(145deg,#312e81,#0f172a)!important}.flowgrid-art{background:radial-gradient(circle at 72% 30%,#38bdf8,transparent 28%),linear-gradient(145deg,#0f2b5f,#0d3b66)!important}
.tag{justify-self:start;border-radius:999px;padding:6px 9px;color:var(--accent-ink);background:var(--accent-soft);font-size:10px;font-weight:900;letter-spacing:.04em;text-transform:uppercase}.catalog-card h3{margin:2px 0 5px;font-size:1.22rem;line-height:1.2}.catalog-card p{margin:0;color:var(--slate-600);font-size:13.5px;line-height:1.6}.open{color:var(--accent-ink);font-size:13px;font-weight:900}.note{margin:26px 0 0;border-left:4px solid var(--accent);border-radius:12px;padding:15px 17px;color:var(--slate-600);background:#fff;box-shadow:0 8px 20px rgba(15,23,42,.04);opacity:1!important;visibility:visible!important;transform:none!important}
.site-footer{border-top:1px solid rgba(148,163,184,.16);padding:26px 0;color:rgba(255,255,255,.68);background:var(--navy-950);font-size:12px}.footer-row{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}.site-footer strong{color:#7dd3fc}
.simulations-library{--accent:#2563eb;--accent-soft:#eff6ff;--accent-ink:#1d4ed8}.games-library{--accent:#7c3aed;--accent-soft:#f5f3ff;--accent-ink:#6d28d9}.tools-library{--accent:#0e7490;--accent-soft:#ecfeff;--accent-ink:#0e7490}
/* Simulation thumbnails */
.thumb-inertia{background:linear-gradient(135deg,#1e3a8a,#0f172a)}.thumb-inertia::before{width:70px;height:70px;right:28px;top:35px;border-radius:50%;background:#facc15;box-shadow:-74px 16px 0 -22px #38bdf8,-122px 16px 0 -34px #fff}.thumb-gravity{background:linear-gradient(135deg,#0f766e,#111827)}.thumb-gravity::before{width:82px;height:82px;right:24px;top:30px;border-radius:50%;background:#60a5fa;box-shadow:-86px 30px 0 -24px #facc15}.thumb-orbit{background:linear-gradient(135deg,#312e81,#020617)}.thumb-orbit::before{width:112px;height:72px;right:18px;top:42px;border:2px solid rgba(255,255,255,.72);border-radius:50%;transform:rotate(-18deg)}.thumb-orbit::after{width:22px;height:22px;right:64px;top:68px;border-radius:50%;background:#facc15;box-shadow:42px -18px 0 -6px #93c5fd}.thumb-blackhole{background:radial-gradient(circle at 62% 48%,#020617 0 22px,#f97316 23px 30px,#7c2d12 31px 38px,#111827 39px),linear-gradient(135deg,#0f172a,#020617)}.thumb-machine{background:linear-gradient(135deg,#78350f,#0f172a)}.thumb-machine::before{width:128px;height:16px;right:20px;top:72px;border-radius:999px;background:#fbbf24;transform:rotate(-18deg);box-shadow:-68px 28px 0 -3px #94a3b8}.thumb-wave{background:linear-gradient(135deg,#0e7490,#111827)}.thumb-wave::before{width:150px;height:54px;right:10px;top:48px;background:repeating-radial-gradient(ellipse at center,transparent 0 10px,rgba(255,255,255,.75) 11px 13px,transparent 14px 22px)}.thumb-ph{background:linear-gradient(135deg,#155e75,#0f172a)}.thumb-ph::before{width:54px;height:86px;right:50px;top:32px;border-radius:8px 8px 22px 22px;background:linear-gradient(#fff 0 24%,#22c55e 24% 100%);box-shadow:-62px 20px 0 -8px #f472b6}.thumb-titration{background:linear-gradient(135deg,#581c87,#0f172a)}.thumb-titration::before{width:20px;height:94px;right:72px;top:22px;border-radius:999px;background:#e9d5ff;box-shadow:0 78px 0 22px rgba(216,180,254,.35),-58px 42px 0 -4px #38bdf8}.thumb-flame{background:linear-gradient(135deg,#7f1d1d,#111827)}.thumb-flame::before{width:72px;height:92px;right:44px;top:30px;border-radius:60% 40% 60% 40%;background:linear-gradient(#fef08a,#f97316,#dc2626);transform:rotate(14deg);box-shadow:-70px 24px 0 -26px #22d3ee}.thumb-atom{background:linear-gradient(135deg,#1e1b4b,#0f172a)}.thumb-atom::before{width:112px;height:54px;right:18px;top:50px;border:2px solid #a5b4fc;border-radius:50%;transform:rotate(26deg)}.thumb-atom::after{width:22px;height:22px;right:64px;top:66px;border-radius:50%;background:#facc15;box-shadow:34px -12px 0 -8px #fff,-38px 14px 0 -8px #fff}.thumb-density{background:linear-gradient(135deg,#0f766e,#164e63)}.thumb-density::before{width:62px;height:72px;right:58px;top:42px;border-radius:10px;background:linear-gradient(#fff 0 16%,#38bdf8 16% 100%);box-shadow:-66px 22px 0 -12px #facc15}.thumb-photo{background:linear-gradient(135deg,#166534,#0f172a)}.thumb-photo::before{width:92px;height:92px;right:24px;top:30px;border-radius:50%;background:#facc15;box-shadow:-78px 42px 0 -28px #22c55e,-108px 18px 0 -34px #86efac}
/* Game thumbnails */
.thumb-game{background:linear-gradient(145deg,#312e81,#111827)}.thumb-game::before{width:84px;height:84px;right:30px;top:34px;border-radius:22px;background:#f59e0b;box-shadow:-72px 28px 0 -18px #38bdf8;transform:rotate(12deg)}.thumb-chess::before{border-radius:50% 50% 18px 18px;background:#f8fafc;box-shadow:-68px 20px 0 -22px #c084fc}.thumb-archery::before{width:92px;height:92px;border:10px solid #f8fafc;border-radius:50%;background:#ef4444;box-shadow:inset 0 0 0 18px #fbbf24;transform:none}.thumb-code::before{border-radius:16px;background:#22c55e;box-shadow:-72px 28px 0 -18px #facc15}.thumb-knight::before{border-radius:50% 50% 20% 20%;background:#cbd5e1;box-shadow:-70px 18px 0 -20px #a78bfa}.thumb-pacman{background:radial-gradient(circle at 70% 48%,#facc15 0 35px,transparent 36px),linear-gradient(145deg,#172554,#111827)}
/* Tool thumbnails */
.thumb-tool{background:linear-gradient(145deg,#0f766e,#0f172a)}.thumb-medcalc::before{width:82px;height:82px;right:34px;top:34px;border-radius:18px;background:#e2e8f0;box-shadow:inset 0 0 0 22px #ef4444}.thumb-piano{background:linear-gradient(145deg,#111827,#4c1d95)}.thumb-piano::before{width:142px;height:74px;right:12px;top:42px;background:repeating-linear-gradient(90deg,#fff 0 18px,#111827 19px 25px,#fff 26px 42px);border-radius:6px}.thumb-asl{background:linear-gradient(145deg,#0e7490,#111827)}.thumb-asl::before{width:100px;height:76px;right:28px;top:38px;border:3px solid #67e8f9;border-radius:12px;background:linear-gradient(135deg,transparent 45%,rgba(103,232,249,.35) 46% 54%,transparent 55%);box-shadow:-78px 26px 0 -22px #a78bfa}
.reveal,.js .reveal,.section-head,.js .section-head,.library-summary,.js .library-summary,.note,.js .note{opacity:1!important;visibility:visible!important;transform:none!important}
@media(max-width:980px){.nav-toggle{display:grid;place-items:center}.nav-links{position:absolute;top:66px;left:20px;right:20px;display:none;align-items:stretch;flex-direction:column;border:1px solid var(--slate-200);border-radius:16px;padding:10px;background:#fff;box-shadow:var(--shadow)}.nav-links.open{display:flex}.nav-links .nav-cta{margin-left:0}.library-hero-grid{grid-template-columns:1fr}.library-switcher{grid-template-columns:repeat(3,1fr);max-width:560px}.library-switcher>span{grid-column:1/-1}.catalog-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:640px){.container,.wrap{width:min(100% - 28px,var(--max))}.brand-copy span{display:none}.brand img{width:38px;height:38px}.nav-shell{min-height:66px}.library-hero{padding:58px 0 48px}.library-hero h1{font-size:clamp(2.25rem,12vw,3.15rem)}.library-lead{font-size:.98rem}.library-switcher{grid-template-columns:1fr}.library-switcher>span{grid-column:auto}.hero-actions .btn{width:100%}#catalog{padding:58px 0 72px}.section-head h2{font-size:clamp(1.8rem,10vw,2.5rem)}.catalog-grid{grid-template-columns:1fr}.catalog-thumb{min-height:145px}.footer-row{display:grid;gap:5px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}


/* v4.3.2 — synchronized navigation + hero responsive correction */
html,body{width:100%;max-width:100%;overflow-x:hidden}
.site-header,.library-hero,#catalog,.site-footer{max-width:100%;overflow-x:clip}
.nav-shell{position:relative;min-width:0}
.brand{min-width:0;flex:1 1 auto}
.brand-copy{min-width:0}
.brand-copy strong,.brand-copy span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.nav-links{flex:0 0 auto}
.library-hero-grid>*{min-width:0}

/* Collapse before desktop navigation or the two-column hero can become cramped. */
@media(max-width:1180px){
  .nav-toggle{display:grid;place-items:center;flex:0 0 44px}
  .nav-links{position:absolute;z-index:80;top:calc(100% - 4px);left:0;right:0;display:none;align-items:stretch;flex-direction:column;gap:2px;border:1px solid var(--slate-200);border-radius:16px;padding:10px;background:#fff;box-shadow:var(--shadow)}
  .nav-links.open{display:flex}
  .nav-links a{width:100%;padding:11px 13px}
  .nav-links .nav-cta{margin-left:0}

  .library-hero{padding:66px 0 54px}
  .library-hero-grid{grid-template-columns:minmax(0,1fr);gap:28px;align-items:start}
  .library-hero h1{max-width:760px;font-size:clamp(2.55rem,6.7vw,4.25rem)}
  .library-lead{max-width:760px}
  .library-switcher{width:100%;max-width:760px;grid-template-columns:repeat(3,minmax(0,1fr));gap:7px}
  .library-switcher>span{grid-column:1/-1}
  .catalog-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}

@media(max-width:760px){
  .container,.wrap{width:min(calc(100% - 28px),var(--max))}
  .site-header{overflow:visible}
  .nav-shell{min-height:66px;gap:12px}
  .brand img{width:38px;height:38px;flex:0 0 38px}
  .brand-copy strong{font-size:13px}
  .brand-copy span{display:none}
  .nav-links{left:0;right:0;top:calc(100% - 2px)}

  .library-hero{padding:48px 0 44px}
  .library-hero-grid{display:block}
  .library-hero h1{max-width:none;font-size:clamp(2.15rem,10.5vw,3.05rem);line-height:1;letter-spacing:-.045em}
  .library-lead{max-width:none;margin-bottom:22px;font-size:.98rem}
  .hero-actions{display:grid;grid-template-columns:1fr;gap:9px}
  .hero-actions .btn{width:100%}
  /* Mobile already has the hamburger menu; avoid a second large navigation card in the hero. */
  .library-switcher{display:none}
  #catalog{padding:52px 0 68px}
  .catalog-grid{grid-template-columns:1fr}
}

@media(max-width:420px){
  .brand-copy strong{max-width:190px}
  .library-hero{padding-top:40px}
}