.viewport-size {
  position: fixed;
  bottom: 0;
  left: 0;
  z-index: 9999;
  background-color: rgba(0, 0, 0, 0.7);
  color: white;
  padding: 0.25em 0.5em;
  font-size: 0.875em;
  white-space: nowrap;
}