styles.css

/*
Following site was used as reference for flipping animation. I modify class names and attributes to 
get flip animation to work correctly and on event click.
http://desandro.github.io/3dtransforms/docs/card-flip.html
*/

.gamebackground {
    margin-top: 200px;
    margin-bottom: 200px;
    margin-right: 30%;
    margin-left: 30%;
    border-style: dashed;
    border-width: 1px
}

.row {
    display: flex;
}

.container { 
    position: relative;
    perspective: 800px;
    margin: auto;
    margin-top: 15px;
    margin-bottom: 15px;
    height: 80px;
    width: 18%;
    border-style: solid;
    border-width: 1px;
  }

.card {
  width: 100%;
  height: 100%;
  position: absolute;
  transform-style: preserve-3d;
  transition: transform 1s;
}

.card div {
  margin: 0;
  display: block;
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
}

.card .fronts {
  background: red;
}
.card .backs {
  background: blue;
  transform: rotateY( 180deg );
}

.card.flipped {
  transform: rotateY( 180deg );
}