:root { color-scheme: light; background: #fff; }
* { box-sizing: border-box; }
body { margin: 0; }
main {
  min-height: 100vh;
  min-height: 100svh;
  display: grid;
  place-items: center;
  padding: 28px;
}
img {
  display: block;
  width: min(760px, 100%);
  height: auto;
  max-height: calc(100svh - 56px);
  object-fit: contain;
}