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

.box {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

a {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 12px;
  color: #bbb;
  text-decoration: none;
}