JSFiddle - React, Tailwind, and code Playground

HTML

<!-- Document Elements: (Media) -->
<video id="media" width="640" height="360" controls autoplay>
  <source src="http://www.sample-videos.com/video/mp4/360/big_buck_bunny_360p_2mb.mp4" type="video/mp4">
</video>

<a href="#media" onClick="assets()">A Link</a>

CSS

position: fixed;
background-color: rgba(0, 0, 0, 0);
width: 37.5rem;
height: 25rem;
left: 50%;
top: 50%;
margin-left: -18.75rem;
margin-top: -12.5rem;
border: none;
z-index: 24;

}
#media {
  -webkit-animation: media;
  -webkit-animation-play-state: paused;
  -webkit-animation-duration: 5s;
  -webkit-transition-timing-function: all ease-in-out;
  -webkit-animation-delay: 2s;
  -webkit-animation-iteration-count: 1;
  -webkit-animation-fill-mode: forwards;
  opacity: 0;
}

/* Animation */
.animation {
  -webkit-animation-play-state: running !important;
}
.timecode {
  -webkit-animation-play-state: running !important;
  -webkit-animation: timecode 15s 1 !important;
}

/*  Assets (Animation) */
@-webkit-keyframes assets {
  0% {
    -webkit-opacity: 1;
  }
  
  100% {
    -webkit-opacity: 0.25;
  }
}

/*  TimeCode (Animation) */
@-webkit-keyframes timecode {
  0% {
    -webkit-opacity: 0.25;
  }
  
  100% {
    -webkit-opacity: 1.0;
  }
}

JavaScript

function assets() {
  "use strict";
  document.getElementById("assets").classList.add("animation");
  document.getElementById("media").classList.add("animation");
}


<!-- Continuity: (Javascript) -->

document.getElementById("media").addEventListener('ended', continuity);

function continuity() {
  "use strict";
  var assets = document.getElementById("assets");
  assets.classList.add("timecode");
}


<!-- Aperture: (Javascript) -->

var callOnce = true;

function aperture() {
  if ((media.duration - media.currentTime) < 5)
    if (callOnce) {
      sync();
      callOnce = false;
    }
}

function sync() {
  "use strict";
  var media = document.getElementById("media");
  media.classList.add("timecode");
  media.classList.remove("animation");
}
setInterval(aperture, 100);