:root {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #172033;
  background: #fffffd;
  line-height: 1.6;
}

* { box-sizing: border-box; }
body { margin: 0; }
header, footer, main { width: min(100% - 2rem, 48rem); margin-inline: auto; }
header { min-height: 5rem; display: flex; align-items: center; justify-content: space-between; }
.brand { color: #1688f8; font-size: 1.5rem; font-weight: 800; text-decoration: none; }
nav { display: flex; flex-wrap: wrap; gap: 1rem; }
nav a { color: inherit; font-weight: 700; }
main { padding-block: 3rem 5rem; }
h1 { font-size: clamp(2rem, 7vw, 3.5rem); line-height: 1.08; margin: 0 0 2rem; }
h2 { margin-top: 2.5rem; line-height: 1.2; }
a { color: #0574dc; }
.notice { border-left: .3rem solid #1688f8; padding: 1rem 1.25rem; background: #f1f7ff; }
footer { border-top: 1px solid #dfe4ec; padding-block: 2rem 4rem; }
@media (prefers-color-scheme: dark) {
  :root { color: #f4f7fb; background: #111724; }
  .notice { background: #17243a; }
  footer { border-color: #344056; }
}