html, body {
  background-color: #333;
}

body {
  text-align: middle;
}

canvas {
  display: block;
  margin-left: auto;
  margin-right: auto;
  
  max-width: 100%;

}

.explanation {
  max-width: 540px;
  margin-left: auto;
  margin-right: auto;
  color: #ddd;
  font-family: sans-serif;
  margin-bottom: 80px;
}

.explanation p {
  line-height: 1.6;
}

.explanation a {
  color: inherit;
}

.eqn {
  margin-left: auto;
  margin-right: auto;
  display: block;
  max-width: 150px;
  width: 150px;
}