mysticsymbolic.github.io/lib/export-svg.css

.overlay-wrapper {
  position: fixed;
  display: flex;
  background-color: rgba(0, 0, 0, 0.9);
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: white;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
}