html, body {
  height: 100%;
  margin: 0;
}

.content {
  position: fixed;          /* an den Viewport gebunden */
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;

  display: flex;
  justify-content: center;  /* horizontal */
  align-items: center;      /* vertikal */
  text-align: center;
}

.footer {
  position: fixed;
  left: 0;
  bottom: 0;
  width: 100%;
  text-align: center;
  background-color: black;
  color: white;
  
}