html,body {
  height: 100%;
 }
body {
  background-color: #000;color:#fff;
  font: normal 1em / 1.5em verdana, sans-serif;
  display: flex;
  flex-direction:column;
  align-items: center;
  justify-content: center;
}
h1 {
  margin: 2em 0;
  font-size: 1.25em;
}