<video autoplay muted onended="this.style.display='none'" style="position: fixed; z-index: -1; top: 0; left: 0; width: 100%; height: 100%; object-fit: cover;">
<source src="linkdelvideo.mp4" type="video/mp4">
</video>




<script>
  var video = document.getElementsByTagName("video")[0];
  video.onended = function() {
    document.body.style.visibility = "visible";
    video.style.display = "none";
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</script>