relative.html

<style>
  /* CSS */
  .selector {
    animation-name: a;
    animation-duration: 3s;
  }
  @keyframes a {
    0% {
      left: 0%;
    }
    100% {
      left: 100%;
    }
  }
</style>

<script>
  /* Scene.js */
  new Scene({
    ".selector": {
      0: {
        left: "0%",
      },
      3: {
        left: "100%",
      },
    }
  }).playCSS();
</script>