:root::before {
  aspect-ratio: 1;
  background:
    radial-gradient(#0f0 28.5em, #0000 calc(28.5em + 1px)),
    radial-gradient(#0000 20em, #fff calc(20em + 1px)) 0 0 / 50% 50%,
    repeating-radial-gradient(#fff 0 2.5em, #000 calc(2.5em + 1px) calc(3.3333em - 1px), #fff 3.3333em) 0 0 / 50% 50%;
  background-blend-mode: lighten;
  content: "";
  font-size: 0.65vmin;
  left: 50%;
  position: absolute;
  top: 50%;
  translate: -50% -50%;
  width: 80em;
}