.viewport-window {
  --vpw-width:    320px;
  --vpw-height:   220px;
  --vpw-radius:   8px;

  --vpw-anchor-x: 50%;
  --vpw-anchor-y: 50%;

  position: relative;
  width:  var(--vpw-width);
  height: var(--vpw-height);
  border-radius: var(--vpw-radius);
  isolation: isolate;

  clip-path: inset(0 round var(--vpw-radius));
}

.viewport-window > .viewport-window-scene {
  position: fixed;
  top:  var(--vpw-anchor-y, 50%);
  left: var(--vpw-anchor-x, 50%);
  transform: translate(-50%, -50%);
  min-width: 1px;
  min-height: 1px;
}

.in-editor .viewport-window > .viewport-window-scene:empty::after {
  content: "Drop scene content here";
  display: flex;
  align-items: center;
  justify-content: center;
  width: 180px;
  height: 120px;
  color: #555;
  font-size: 12px;
  border: 1px dashed #333;
  border-radius: 4px;
  pointer-events: none;
}