In the index.html file, append the following opponent's card object after our player's cards:

<div class="card opponent out">
  <div class="front face">
    <div class="power">100</div>
  </div>
  <div class="back face">back</div>
</div>

The opponent's card is going in from the left side of the game scene. We define the style of placement and also the out and in classes for the JavaScript to toggle:

.card.opponent {
  bottom: 250px;
}
.card.opponent.out {
  left: -200px;
}
.card.opponent.in {
  transition-delay:.8s;
  left: 40px;
}

During the setup inside the gameScene module, we create a Card instance for that element so that we can get the power...