body {
  font:
    17px/1.7 system-ui,
    -apple-system,
    "PingFang SC",
    sans-serif;
  margin: 0;
  background: #f5f6fa;
  color: #202430;
}
main {
  max-width: 760px;
  margin: auto;
  padding: 48px 24px;
}
h1 {
  font-size: 32px;
  line-height: 1.25;
}
h2 {
  font-size: 22px;
  margin-top: 32px;
}
a {
  color: #234dcc;
}
nav {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}
hr {
  margin: 48px 0;
  border: 0;
  border-top: 1px solid #d5d8e0;
}
footer {
  margin-top: 40px;
  color: #555;
}
@media (prefers-color-scheme: dark) {
  body {
    background: #15171d;
    color: #eee;
  }
  a {
    color: #9bb5ff;
  }
  hr {
    border-top-color: #333;
  }
  footer {
    color: #ccc;
  }
}