#demo{
  user-select:none;
  text-align:center;
}
#demo b{
  display:inline-block;
  width:20%;
  height:20vw;
  line-height:20vw;
  text-align:center;
  font-size:8vw;
  font-weight:bold;
  border:1px solid #000;
  border-bottom:8px solid #000;
  box-sizing:border-box;
  font-family:serif;
}
#demo b.space{
  color:transparent;
}
#demo b.select{
  color:#555;
}
#demo b.choice{
  background-color:#ccc;
  color:#555;
}
#demo b.choice:hover{
  background-color:#eee;
  color:#000;
  cursor:pointer;
}
#demo b.ok{
  background-color:#afa;
  color:#000;
}
#demo b.ng{
  background-color:#faa;
}
button{
  width:100%;
  padding:12px;
  font-size:5vw;
  box-sizing:border-box;
}
#demo a{
  display:inline-block;
  padding:12px;
}

#controls{
  margin:20px;
}
#controls label{
  display:inline-block;
  width:24%;
  height:10vw;
  font-size:8vw;
}
#controls input{
  transform: scale(4);
  transform-origin: bottom center;
  margin:20px;
}