body {
  font-family: Arial, Helvetica, sans-serif; 
  max-width: 40em;
  line-height: 20px;
}

#content {
  margin: 20px;
  padding: 10px 20px;
  border-width: 1px;
  border-style: solid;
  border-color: #000;
}

code {
  background-color: #eee;
  padding: 5px 5px;
}

@media screen and (max-width: 400px) {
  h1 {
    font-size: 1.5em;
  }
}