html, body {
  height: 100%;
  margin: 0;
  overscroll-behavior: contain;
  overflow: hidden;
  background: #FFFFFF;
}
body {
  display: flex;
  justify-content: center;
  align-items: center;
}
#wrapper {
  position: relative;
  margin: 20px auto;
}
#game-container {
  position: relative;
  display: inline-block;
  line-height: 0;
}
#game-container canvas {
  display: block;
}
.x-link {
  position: absolute;
  top: 650px;
  left: -52px;
  padding: 16px 14px;
  background: #DDDDDD;
  color: #000;
  text-decoration: none;
  border-radius: 6px;
  font-size: 14px;
  z-index: 10;
}
.x-link:hover { background: #888888; }