<style>
  .card {
    width: 200px;
    height: 200px;
    margin: 10px auto;
    position: relative;
  }

  .card__panel {
    border: 1px solid black;
    background: blue;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
  }
</style>

<div class="card">
  <div class="card__panel card__panel--front">
  </div>
  <div class="card__panel card__panel--inside-left">
  </div>
  <div class="card__panel card__panel--inside-right">
  </div>
</div>

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.