:root{
  --navy:#0A1628;--navy2:#12213C;--blue:#2563EB;--blue-d:#1D4ED8;--sky:#60A5FA;
  --surface:#F8FAFC;--white:#fff;--ink:#0F172A;--ink2:#475569;--ink3:#64748B;--ink4:#94A3B8;
  --line:#E2E8F0;--tag:#EFF6FF;
  --sans:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
  --mono:ui-monospace,'SF Mono','JetBrains Mono',Menlo,monospace;
  --r-card:16px;--r-btn:11px;--max:1200px;
  --sh:0 18px 40px -22px rgba(10,22,40,.45);--sh-h:0 26px 54px -22px rgba(10,22,40,.55);
  --sh-b:0 16px 30px -12px rgba(37,99,235,.55);
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{font-family:var(--sans);color:var(--ink);line-height:1.6;background:var(--white);-webkit-font-smoothing:antialiased}
img,svg{display:block;max-width:100%}
h1,h2,h3,h4{font-family:var(--sans);font-weight:900;letter-spacing:-.045em;line-height:1.05;color:var(--ink);text-wrap:balance}
h1{font-size:clamp(38px,5.2vw,60px)}h2{font-size:clamp(30px,3.6vw,42px)}
h3{font-size:26px;letter-spacing:-.03em;font-weight:800}h4{font-size:19px;letter-spacing:-.02em;font-weight:800}
p{text-wrap:pretty}
a{color:var(--blue);text-decoration:none}a:hover{color:var(--blue-d);text-decoration:underline}
.wrap{max-width:var(--max);margin:0 auto;padding:0 clamp(20px,5vw,48px)}
.eyebrow{font-family:var(--mono);font-size:13px;letter-spacing:.14em;text-transform:uppercase;color:var(--blue)}
.btn{display:inline-block;font-size:16px;font-weight:600;padding:16px 30px;border-radius:var(--r-btn);
  text-decoration:none;transition:transform .15s ease,box-shadow .15s ease,border-color .15s ease,background .2s ease;cursor:pointer;border:none}
.btn:hover{text-decoration:none;transform:translateY(-2px)}
.btn-p{background:var(--blue);color:#fff!important;box-shadow:var(--sh-b)}
.btn-p:hover{background:var(--blue-d);box-shadow:0 20px 36px -12px rgba(37,99,235,.7)}
.btn-g{background:#fff;color:var(--navy)!important;border:1px solid #CBD5E1;padding:15px 29px}
.btn-g:hover{border-color:#94A3B8}
.btn-gd{background:transparent;color:#fff!important;border:1px solid rgba(255,255,255,.28);padding:15px 29px}
.btn-gd:hover{border-color:rgba(255,255,255,.55)}
.card{background:#fff;border-radius:var(--r-card);padding:28px;box-shadow:var(--sh);transition:box-shadow .2s,transform .2s}
a.card:hover{box-shadow:var(--sh-h);transform:translateY(-3px);text-decoration:none}
.tag{display:inline-block;background:var(--tag);color:var(--blue-d);font-size:12.5px;font-weight:500;border-radius:20px;padding:5px 12px;white-space:nowrap}
.grid{display:grid;gap:22px}
.g2{grid-template-columns:repeat(auto-fit,minmax(300px,1fr))}
.g3{grid-template-columns:repeat(auto-fit,minmax(260px,1fr))}
.g4{grid-template-columns:repeat(auto-fit,minmax(228px,1fr))}
section{padding:clamp(56px,7vw,96px) 0}
.sec-dark{background:var(--navy);color:#fff}
.sec-dark h1,.sec-dark h2,.sec-dark h3,.sec-dark h4{color:#fff}
.sec-dark p{color:#AEBCD4}
.sec-surface{background:var(--surface)}
.lede{font-size:clamp(16px,1.6vw,19px);line-height:1.65;color:var(--ink2);max-width:62ch}
.sec-dark .lede{color:#AEBCD4}
/* header */
.site-head{background:var(--navy);position:sticky;top:0;z-index:50}
.site-head .wrap{display:flex;align-items:center;gap:24px;min-height:76px}
.site-head a{color:#fff}
.brand{display:flex;align-items:center;gap:11px;font-weight:800;font-size:18px;letter-spacing:-.03em;flex:none}
.brand:hover{text-decoration:none}
.brand .dot{color:var(--sky)}
nav.main{margin-left:auto;display:flex;gap:26px;align-items:center;flex-wrap:wrap}
nav.main a{font-size:15px;font-weight:500;color:#C3D0E4}
nav.main a:hover{color:#fff;text-decoration:none}
nav.main a.here{color:#fff}
nav.main .btn{padding:11px 20px;font-size:14.5px}
/* footer */
.site-foot{background:var(--navy);color:#AEBCD4;padding:clamp(48px,6vw,72px) 0 36px;font-size:14.5px}
.site-foot h4{color:#fff;font-size:13px;font-family:var(--mono);letter-spacing:.12em;text-transform:uppercase;font-weight:500;margin-bottom:16px}
.site-foot a{color:#AEBCD4;display:block;margin-bottom:9px}
.site-foot a:hover{color:#fff}
.foot-legal{border-top:1px solid rgba(255,255,255,.1);margin-top:44px;padding-top:26px;font-size:13px;color:#8FA3C4;display:flex;flex-wrap:wrap;gap:18px;justify-content:space-between}
.foot-legal a{display:inline;margin:0}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .btn:hover,a.card:hover{transform:none}
  *{animation:none!important}
}

.auth-wrap{min-height:calc(100vh - 76px);display:flex;align-items:center;justify-content:center;padding:56px 24px;background:#0A1628;background-image:radial-gradient(90% 70% at 50% 0%,rgba(37,99,235,.22),rgba(37,99,235,0) 62%)}
.auth-card{width:100%;max-width:452px;background:#101d33;border:1px solid #22314d;border-radius:20px;padding:40px}
.auth-card h1{font-size:31px;line-height:1.1;letter-spacing:-.035em;margin:0 0 10px;color:#fff}
.auth-card .sub{color:#8FA3C4;font-size:15px;line-height:1.6;margin:0 0 28px}
.fld{margin-bottom:18px}
.fld label{display:block;font-size:13px;font-weight:600;color:#C3D0E4;margin-bottom:7px}
.fld input[type=email],.fld input[type=password]{width:100%;background:#0A1628;border:1px solid #2b3d5e;border-radius:11px;padding:14px 15px;color:#fff;font:inherit;font-size:15px}
.fld input:focus{outline:none;border-color:#60A5FA;box-shadow:0 0 0 3px rgba(96,165,250,.18)}
.fld .hint{font-size:12.5px;color:#7d8fab;margin-top:6px}
.chk{display:flex;gap:11px;align-items:flex-start;margin-bottom:16px;cursor:pointer}
.chk input{margin-top:3px;width:17px;height:17px;accent-color:#2563EB;flex:0 0 17px}
.chk span{font-size:14px;line-height:1.5;color:#C3D0E4}
.auth-btn{width:100%;background:#2563EB;color:#fff;border:0;border-radius:11px;padding:16px;font:inherit;font-size:16px;font-weight:600;cursor:pointer;box-shadow:0 16px 30px -12px rgba(37,99,235,.6);transition:background .2s,transform .15s}
.auth-btn:hover{background:#1D4ED8;transform:translateY(-1px)}
.auth-btn:disabled{opacity:.55;cursor:not-allowed;transform:none}
.auth-alt{text-align:center;margin-top:22px;font-size:14.5px;color:#8FA3C4}
.auth-alt a{color:#60A5FA;font-weight:600}
.auth-msg{border-radius:11px;padding:13px 15px;font-size:14px;line-height:1.5;margin-bottom:20px;display:none}
.auth-msg.err{display:block;background:#2c1420;border:1px solid #7d2540;color:#ff96ac}
.auth-msg.ok{display:block;background:#0e2a22;border:1px solid #1d6b50;color:#5fd6a9}
.dash-hero{background:#0A1628;background-image:radial-gradient(80% 70% at 20% 0%,rgba(37,99,235,.2),rgba(37,99,235,0) 60%);padding:52px 0 44px}
.dash-grid{display:grid;gap:18px;grid-template-columns:repeat(auto-fit,minmax(260px,1fr))}
.dash-card{background:#101d33;border:1px solid #22314d;border-radius:16px;padding:26px}
.dash-card h3{font-size:18px;margin:0 0 8px;color:#fff}
.dash-card p{color:#8FA3C4;font-size:14.5px;line-height:1.6;margin:0 0 16px}
.dash-stat{font-size:34px;font-weight:800;letter-spacing:-.03em;color:#fff;line-height:1;margin-bottom:6px}
.next-card{background:linear-gradient(135deg,#12213C,#0A1628);border:1px solid #2b3d5e;border-radius:20px;padding:32px;margin-bottom:26px}
html.gated{visibility:hidden}

/* ---- lesson figures ---- */
.fig{background:#0A1628;border-radius:var(--r-card);padding:30px;margin:34px 0;overflow:hidden}
.fig-cap{font-family:var(--mono);font-size:11.5px;letter-spacing:.13em;text-transform:uppercase;color:#60A5FA;margin-bottom:18px}
.fig-note{font-size:14px;line-height:1.6;color:#8FA3C4;margin-top:18px}
.fig-btn{background:#2563EB;color:#fff;border:0;border-radius:10px;padding:11px 20px;font:inherit;font-size:14.5px;font-weight:600;cursor:pointer;transition:background .18s,transform .12s}
.fig-btn:hover{background:#1D4ED8;transform:translateY(-1px)}
.fig-btn:disabled{opacity:.4;cursor:default;transform:none}
.fig-bar{display:flex;gap:9px;align-items:center;flex-wrap:wrap;margin-top:20px}
.fig-step{font-family:var(--mono);font-size:12px;color:#7D8FAB;margin-left:4px}
.tok{display:inline-block;border-radius:7px;padding:7px 11px;margin:0 4px 8px 0;font-family:var(--mono);font-size:15px;
  background:#16243D;color:#C3D0E4;border:1px solid #2B3D5E;opacity:0;transform:translateY(7px);transition:opacity .3s,transform .3s,background .3s,color .3s}
.tok.in{opacity:1;transform:none}
.tok.hot{background:#2563EB;color:#fff;border-color:#60A5FA}
.tok-id{display:block;font-size:10.5px;color:#7D8FAB;margin-top:3px}
.tok.hot .tok-id{color:#BFD5FF}
@media (prefers-reduced-motion:reduce){.tok{transition:none}.fig-btn:hover{transform:none}}

/* --- header v2 --- */
.site-head{background:var(--navy);position:sticky;top:0;z-index:50}
.site-head>.wrap{display:flex;align-items:center;min-height:70px;gap:20px;position:relative}
.nav-sheet-inner{display:block;width:100%;max-width:var(--maxw,1200px);margin:0 auto;padding:0 clamp(18px,4vw,32px)}
.site-head{overflow-x:clip}
.brand{flex:0 1 auto;min-width:0}
.brand span{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
nav.main{margin-left:auto;display:flex;align-items:center;gap:28px;flex-wrap:nowrap}
nav.main a{position:relative;font-size:14.5px;font-weight:500;color:rgba(255,255,255,.72);padding-bottom:3px;white-space:nowrap;transition:color .2s ease}
nav.main a:hover{color:#fff}
nav.main a .nav-rule{position:absolute;left:0;bottom:0;height:2px;width:100%;border-radius:2px;background:var(--acc,#60A5FA);transform:scaleX(0);transform-origin:left center;transition:transform .3s cubic-bezier(.4,0,.2,1)}
nav.main a:hover .nav-rule,nav.main a[aria-current="page"] .nav-rule{transform:scaleX(1)}
nav.main a[aria-current="page"]{color:#fff}
.nav-dash{display:flex;align-items:center;gap:7px;font-size:14px;font-weight:600;color:rgba(255,255,255,.9)!important;border:1px solid rgba(255,255,255,.22);border-radius:9px;padding:9px 17px;padding-bottom:9px!important;transition:border-color .2s ease,background .2s ease}
.nav-dash:hover{border-color:rgba(255,255,255,.42);background:rgba(255,255,255,.06)}
.nav-dash .nav-rule{display:none}
.nav-dash .nav-dot{width:6px;height:6px;border-radius:50%;background:#15803D;box-shadow:0 0 8px 1px rgba(21,128,61,.85);flex:none}
.nav-burger{display:none;margin-left:auto;width:38px;height:38px;border-radius:10px;background:rgba(255,255,255,.07);border:1px solid rgba(255,255,255,.12);flex-direction:column;align-items:center;justify-content:center;gap:4px;cursor:pointer;padding:0}
.nav-burger span{width:16px;height:2px;border-radius:2px;background:#fff;transition:transform .26s ease,opacity .18s ease}
.nav-burger[aria-expanded="true"] span:nth-child(1){transform:translateY(6px) rotate(45deg)}
.nav-burger[aria-expanded="true"] span:nth-child(2){opacity:0}
.nav-burger[aria-expanded="true"] span:nth-child(3){transform:translateY(-6px) rotate(-45deg)}
.nav-sheet{display:none}

@media (max-width:860px){
  .site-head>.wrap{min-height:58px}
  .brand span{font-size:16px}
  nav.main{display:none}
  .nav-burger{display:flex}
  .nav-sheet{display:block;position:absolute;left:0;right:0;top:100%;background:var(--navy);border-bottom:1px solid rgba(255,255,255,.07);overflow:hidden;max-height:0;opacity:0;transition:max-height .36s cubic-bezier(.4,0,.2,1),opacity .24s ease}
  .site-head{position:sticky}
  .site-head.open .nav-sheet{max-height:420px;opacity:1}
  .nav-sheet-inner{padding-top:4px;padding-bottom:16px}
  .nav-sheet a{display:flex!important;width:100%;flex:none;align-items:center;gap:11px;padding:15px 2px;font-size:17px;font-weight:600;color:#fff!important;border-bottom:1px solid rgba(255,255,255,.08)}
  .nav-sheet a .nav-rule{display:none}
  .nav-sheet a:last-child{border-bottom:none}
  .nav-sheet .nav-dot2{width:7px;height:7px;border-radius:50%;flex:none;background:var(--acc,#60A5FA)}
}

/* hero v2 — drifting grid, orbiting accent, growth bars */
@keyframes mcgDrift{0%,100%{transform:translate(0,0)}50%{transform:translate(7px,-5px)}}
@keyframes mcgOrbit{0%,100%{transform:translate(0,0);opacity:.75}50%{transform:translate(6px,-9px);opacity:1}}
@keyframes mcgBar{from{width:0}to{width:var(--w)}}
.hero-grid{position:absolute;inset:-72px;opacity:.5;background-image:linear-gradient(rgba(96,165,250,.09) 1px,transparent 1px),linear-gradient(90deg,rgba(96,165,250,.09) 1px,transparent 1px);background-size:72px 72px;animation:mcgDrift 16s ease-in-out infinite}
.growth{display:grid;grid-template-columns:132px 1fr 46px;align-items:center;gap:12px;padding:7px 0}
.growth .g-name{font-size:13px;font-weight:500;color:rgba(255,255,255,.82);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.growth .g-track{display:block;height:9px;border-radius:99px;background:rgba(255,255,255,.08);overflow:hidden}
.growth .g-fill{display:block;height:100%;border-radius:99px;background:var(--acc);width:0;box-shadow:0 0 12px -2px var(--acc);animation:mcgBar .9s cubic-bezier(.32,.9,.36,1) forwards;animation-delay:var(--d)}
.growth .g-pct{font-family:var(--mono);font-size:12.5px;font-weight:500;color:var(--acc);text-align:right}
@media (max-width:620px){.growth{grid-template-columns:100px 1fr 58px;gap:9px;padding:5px 0}.growth .g-name{font-size:12px}.growth .g-pct{font-size:11.5px;white-space:nowrap}}
@media (prefers-reduced-motion:reduce){.hero-grid,.growth .g-fill{animation:none}.growth .g-fill{width:var(--w)}}