/* No page background: the ball sits on whatever is behind the page. */
html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: transparent;
}

.stage {
  position: fixed;
  inset: 0;
  cursor: default;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}
.stage.is-over { cursor: grab; }
.stage.is-dragging { cursor: grabbing; }

.stage canvas {
  display: block;
  width: 100%;
  height: 100%;
  opacity: 0;
  transition: opacity 500ms ease;
}
.stage.is-ready canvas { opacity: 1; }