body main article {
  position: absolute;
  width: 720px;
  top: 50px;
  bottom: 0;
  padding: 40px;
  display: block;
  box-sizing: border-box;
  background: rgba(0, 0, 0, 0.5);
  overflow: auto;
}

body main article h1,
body main article h2 {
  color: white;
  font: bold 23px "Gill Sans", Arial, sans-serif;
  margin: 0;
  padding: 0 0 20px 0;
}

body main article h2 {
  font-size: 16px;
  padding: 20px 0 10px 0;
}

body main article p,
body main article input,
body main article textarea,
body main article address,
body main article pre,
body main article figcaption {
  color: white;
  font: 16px "Gill Sans", Arial, sans-serif;
  margin: 16px 0;
}

body main article pre {
  font-family: monospace;
}

body main article h2 + p {
  margin-top: 0;
}

body main article a {
  color: white;
  font: 16px "Gill Sans", Arial, sans-serif;
}

@media (max-width: 1000px) {
  
  body.article main article {
    width: calc(100% - 280px);
  }
  
}

@media (max-device-width: 800px) {
  
  body main article,
  body.article main article {
    position: static;
    float: none;
    display: block;
    width: 100%;
    height: auto;
    box-sizing: border-box;
  }
  
}