html, body {
  height: 100%;
}

body {
  background-color: #000;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

footer {
  position: fixed;
  bottom: 0;
  left: 0;
  max-width: 100vw;
  color: white;
  background-color: black;
  padding: 0.5em 1em;
  border-top-right-radius: 0.5em;
}