:root {
  color-scheme: light dark;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f6f7f9;
  color: #18202c;
  font-synthesis: none;
}
* { box-sizing: border-box; }
body {
  min-height: 100svh;
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}
main { width: min(100%, 32rem); }
.mark {
  display: block;
  width: 2.5rem;
  height: 3px;
  margin-bottom: 1.75rem;
  background: currentColor;
}
h1 {
  margin: 0 0 0.8rem;
  font-size: clamp(2rem, 7vw, 3rem);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.045em;
}
p { margin: 0; color: #586273; font-size: 1.05rem; line-height: 1.6; }
@media (prefers-color-scheme: dark) {
  :root { background: #11151b; color: #edf0f5; }
  p { color: #aeb8c6; }
}