:root {
  color-scheme: light dark;
}

body {
  max-width: 650px;
  margin: 40px auto;
  padding: 0 12px;
  font: 18px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "Noto Sans JP", "Noto Sans", sans-serif;
  color: #444;
  background: #fff;
}

h1,
h2,
h3 {
  line-height: 1.2;
}

section {
  margin-block: 3.5rem;
}

article {
  margin-block: 2.75rem;
}

article h3 {
  margin-bottom: 0;
}

article h3 + ul {
  margin-top: 0.75rem;
}

a {
  text-underline-offset: 0.15em;
}

hr {
  margin-block: 2.5rem 1rem;
  border: 0;
  border-top: 1px solid #bbb;
}

@media (prefers-color-scheme: dark) {
  body {
    color: #c9d1d9;
    background: #0d1117;
  }

  a:link {
    color: #58a6ff;
  }

  a:visited {
    color: #8e96f0;
  }

  hr {
    border-top-color: #30363d;
  }
}