html {
  color-scheme: dark light;
}
body {
  max-width: 40em;
  margin-right: auto;
  margin-left: auto;
  padding-right: 1em;
  padding-left: 1em;
  font-family: system-ui, sans-serif;
  line-height: 1.5;
}
h3, h4, h5, h6 {
  font-size: 100%;
}