Edit in JSFiddle

<!DOCTYPE html>
<html>
<head>
  <title>Hit Me</title>
  <link rel="stylesheet" type="text/css" href="styles.css">
</head>
<body>

<div class="wrapper">
  
  <input id="flip" type="checkbox" name="flip-card">
  
  <label for="flip">
    
    <div class="card">
      
      <div class="front">
        <img src="http://www.arcane.org/assets/hitme-card-back.png" style="height: 100%">
      </div>
      
      <div class="back">
        <img src="http://www.arcane.org/assets/hitme-card-front.png">
      </div>
    </div>
        
  </label>
  
 </div>

 </body>
</html>
* {
  box-sizing: border-box;
}
body {
  background-image: url("http://www.arcane.org/assets/hitme-background.jpg");
}
a {
  text-decoration: none;
}
.wrapper {
  max-width: 50rem;
  width: 100%;
  margin: 5rem auto;
  text-align: center;
}
#flip {
  display: none;
}
.card {
  padding: 0;
  display: block;
  width: 20rem;
  height: 32rem;
  margin: 0 auto;
  transform-style: preserve-3d;
}
#flip:not(:checked) + label > .card {
  transform: rotateY(0deg);
  transition: transform 0.25s;
}
#flip:checked + label > .card {
  transform: rotateY(180deg);
  transition: transform 0.25s;
}
.front,
.back {
  overflow: hidden;
  position: absolute;
  width: 100%;
  height: 100%;
  box-shadow: rgba(0,0,0,0.2) 0 0 3rem 0, rgba(0,0,0,0.1) 0 0 1rem 0;
}
.front {
  transform: translateZ(2px);
  background: #a3ba60;
  border-radius: 2rem 2rem;
  color: #eaf5d7;
}
.front:after {
  content: 'HIT ME';
  background-color:rgba(105,105,105,0.5);
  white-space: nowrap;
  position: absolute;
  top: 14rem;
  left: 5.5rem;
  right: 5.5rem;
  font-size: 2rem;
  font-weight: 800;
  line-height: 60px;
  cursor: pointer;
  visibility: hidden;
  opacity: 0;
  transition: opacity 0.1s;
}
.front:hover:after {
  visibility: visible;
  opacity: 1;
  transition: opacity 0.35s;
}
.back {
  border-radius: 2rem 2rem;
  transform: translateZ(-2px) rotateY(180deg);
  background: #fff;
  border: 1px solid #2d5077;
  padding-top: 1.7rem;
}
img {
    height: 100%;
    width: 100%;
}