:root {
  --body-color: #2d2d2d;
  --brand-color: dodgerblue;
}

* {
  box-sizing: border-box;
}

body {
  font-family: system-ui, sans-serif;
  line-height: 1.5;
  margin: 0 auto;
  max-width: 66ch;
  padding: 1em;
}

a,
a:visited {
  color: var(--body-color);
  font-weight: bold;
}

a:hover {
  color: var(--brand-color);
}

@media (prefers-color-scheme: dark) {
  body {
    background: var(--body-color);
    color: white;
  }

  a,
  a:visited {
    color: white;
  }
}