html {
  font-family: system-ui, sans-serif;
  line-height: 1.6;
}
body {
  margin: 0;
  padding: 3rem 1.5rem;
}
main {
  max-width: 720px;
  margin: auto;
}
h1 {
  font-size: 2.2rem;
}
.lead {
  font-size: 1.15rem;
}
section {
  margin-top: 3rem;
}
footer {
  margin-top: 5rem;
  font-size: .85rem;
  opacity: .6;
}