body {
  margin: 40px auto;
  max-width: 650px;
  padding: 0 10px;
  line-height: 1.6;
  font-size: 18px;
  color: #000;
  background: #fff;
}

.dark {
  color-scheme: dark;
}

.dark body {
  color: #fff;
  background: #000;
}

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

a {
  color: inherit;
}

img {
  max-width: 100%;
}

#theme {
  float: right;
}

form {
  margin: 1em 0;
}

pre {
  overflow-x: auto;
}