:root { --paper:#f3f5f5; --ink:#13262b; --muted:#536a70; --teal:#105a66; }
@media (prefers-color-scheme: dark) { :root { --paper:#0f1a1d; --ink:#e6eff0; --muted:#9db3b8; --teal:#4fc3d6; } }
body { margin:0; min-height:100vh; display:grid; place-items:center; background:var(--paper); color:var(--ink);
  font-family:"Segoe UI", system-ui, -apple-system, sans-serif; line-height:1.6; }
main { max-width:36rem; padding:2rem; }
.mark { width:96px; height:auto; }
h1 { font-size:clamp(1.8rem,4vw,2.4rem); line-height:1.15; margin:1rem 0; }
p { color:var(--muted); }
a { color:var(--teal); }
a:focus-visible { outline:3px solid var(--teal); outline-offset:3px; }