*,
html {
  margin: 0;
  padding: 0;
  background-color: #000000;
}

.center {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  -webkit-transform: translate(-50%, -50%);
}