html {box-sizing: border-box;}*, *:before, *:after {box-sizing: inherit;}

body {
  padding-bottom: 6rem;
}

.intro {
  max-width: 600px;
  font-size: 30px;
  font-family: sans-serif;
  padding: 3rem 1rem 3rem 1rem;
  margin: 0 auto;
}

img {
  display: block;
  max-width: 100%;
  margin: 0 auto;
  border: 6px solid #333;
}

@media (max-width: 600px) {
  .intro {
    font-size: 20px;
  }
}