body {
    font-family: helvetica, sans-serif;
    margin: 0;
    line-height: 1.5;
  }
  header, main, footer { padding: 1rem;}
* { box-sizing: border-box;}
  header h1,
  main h2 { margin: 0; padding: 0;}
  
  a:link, a:visited {
      color: blue;
      text-decoration: none;
  }
  a:hover { text-decoration: underline;}
  a:active { color: white; background-color: blue;}
  footer {
    margin-top: 2rem;
    padding: 0.5rem;
    background-color: rgb(240, 240, 240);
    border-top: thin solid black;
  }
  ul > li > p { margin-left: 2rem; margin-top: 0.25rem;}
  img.screenshot { border: thin solid rgb(125,125,125);max-width: 100%;}