* {
 box-sizing: border-box;
}

html {
 background-image: url("keith-haring-bg.png");
 background-size: 700px;
}

body {
 background-color: white;
 width:600px;
 max-width:90%;
 margin:auto;
 margin-top:1em;
 margin-bottom: 2em;
 padding:1.5em;
}

a:hover, a:focus {
  text-decoration-thickness: 2px;
}

pre {
 font-size:1em; 
}

img {
  max-width:100%;
  margin:auto;
  display:block;
}