html, body { height: 100%; width: 100%; margin: 0; }
  body {
    color: white;
    animation: 10000ms ease-in-out infinite color-change;
  }
  a {
    color:aqua;
  }

  .bg {
    z-index: -1;
    position: absolute;
    margin: 0;
    height: 100%;
    width: 100%;
  }
  img.cat {
    height: 20%;
    width: 10%;
    margin: 0;
    padding: 0;
    display: inline-block;
    float: left;
    clear: right;
  }
  .right {
    transform: scaleX(-1);
    float: right;
    clear: left
  }
  .overlay {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    animation: 10000ms ease-in-out infinite color-change;
    opacity:.5
  }

  .front {
    z-index: 5;
    position: absolute;
  }
  .center {
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
  }
  .card {
    background-color: #000000d8;
    padding: 25px 50px;
    border-radius: 25px;
  }


@keyframes color-change {
  0% {
    background-color: teal;
  }
  20% {
    background-color: gold;
  }
  40% {
    background-color: indianred;
  }
  60% {
    background-color: violet;
  }
  80% {
    background-color: green;
  }
  100% {
    background-color: teal;
  }
}