body {
  font-family: sans-serif;
  margin: 0;
  padding: 0;
  line-height: 1.6;
}
nav {
  background: #222;
  padding: 1em;
  text-align: center;
}
nav a {
  color: #fff;
  margin: 0 1em;
  text-decoration: none;
}
.hero {
  text-align: center;
  padding: 4em 2em;
  background: #f4f4f4;
}
.btn {
  background: #000;
  color: #fff;
  padding: 0.5em 1.2em;
  display: inline-block;
  text-decoration: none;
  margin-top: 1em;
}
main {
  padding: 2em;
}