body {
  margin: 0;
  overflow: hidden;
  background-color: skyblue;
}

.leaf {
  position: absolute;
  width: 50px;
  height: 100px;
  background-color: green;
  border-radius: 50%;
  transform-origin: center;
  opacity: 0.7;
  animation-name: sway;
  animation-duration: 2s;
  animation-timing-function: ease-in-out;
  animation-iteration-count: infinite;
  transition: transform 0.3s;
}


@keyframes sway {
  0% { transform: translateX(0) rotate(0deg); }
  50% { transform: translateX(var(--sway-distance)) rotate(var(--sway-angle)); }
  100% { transform: translateX(0) rotate(0deg); }
}