*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  background:#05060b;
}

/* This renders the mock pixel-for-pixel (scaled to fit screen) */
.stage{
  width:100vw;
  height:100vh;
  display:flex;
  align-items:center;
  justify-content:center;
  overflow:hidden;
}

.mock{
  width:100%;
  height:100%;
  object-fit:contain; /* exact look without cropping */
  image-rendering:auto;
}