body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
               Roboto, Helvetica, Arial, "Noto Sans",
               "Liberation Sans", sans-serif;
  line-height: 1.6;
  max-width: 900px;
  margin: 2rem auto;
  padding: 0 1rem;
  color: #222;
  background-color: #ffffff;
}

h1, h2, h3 {
  line-height: 1.3;
  margin-top: 2rem;
}

h1 {
  font-size: 2.2rem;
}

h2 {
  font-size: 1.6rem;
}

h3 {
  font-size: 1.2rem;
}

a {
  color: #0056b3;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

hr {
  border: none;
  border-top: 1px solid #ddd;
  margin: 2rem 0;
}

nav {
  margin-bottom: 2rem;
}

nav a {
  margin-right: 1.2rem;
  font-weight: 500;
}