#holder { border: 10px dashed #ccc; width: 300px; height: 300px; margin: 20px auto;}
#holder.hover { border: 10px dashed #333; }

.hidden { display:none; }
.game-image {
  position: absolute;
  margin-left: auto;
  margin-right: auto;
  left: 0;
  right: 0;
}
.game-canvas {
  position: absolute;
  z-index: 2;
}
.limit-height {
  max-height: 100%;
}
body, html, .container-fluid {
  height: 100%;
}