:root {
  color-scheme: dark;
  --background: #0d141e;
  --foreground: #edf4f9;
  --muted: #b5c1ce;
  --accent: #90e6cc;
  --border: #304154;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--background);
  color: var(--foreground);
  font: 17px/1.65 system-ui, sans-serif;
}
header, main, footer {
  width: min(100% - 2.5rem, 760px);
  margin-inline: auto;
}
header, footer { padding: 1.4rem 0; }
header { border-bottom: 1px solid var(--border); }
footer {
  margin-top: 3rem;
  border-top: 1px solid var(--border);
}
main { padding-top: 2.75rem; }
h1, h2 { line-height: 1.2; }
h1 { font-size: clamp(2.4rem, 7vw, 4rem); margin: 0 0 1rem; }
h2 { margin: 2rem 0 0.75rem; font-size: 1.35rem; }
p, li { color: var(--muted); }
a { color: var(--accent); text-underline-offset: 0.2em; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
nav { display: flex; flex-wrap: wrap; gap: 0.5rem 1.5rem; }
.brand { font-weight: 700; }