body {
  font-family: sans-serif;
}

.container {
  border: solid #6d088b;
  position: relative;
  width: 100%;
}

.ball {
  height: 30%;
  aspect-ratio: 1 / 1;
  background-color: #00ffff;
  opacity: 0.5;
  position: absolute;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  pointer-events: none;
}