html, body {
  margin: 0;
  height: 100%;
  background: #2a5d55; /* dark teal: complements the magenta, keeps the black outline visible */
  color-scheme: dark;
}
body {
  display: grid;
  place-items: center;
  min-height: 100vh;
  min-height: 100dvh;
}
img {
  display: block;
  width: auto;
  height: auto;
  max-width: min(540px, 90vw);
  max-height: 90vh;
  max-height: 90dvh;
  image-rendering: pixelated; /* keep pixel art crisp when scaled */
}