#demo{
  display:grid;
  justify-items: center;
  align-items: center; 
}
footer,
#code,
pre{
  display:none;
}

input,button{
  width:100%;
  font-size:24px;
  padding:12px;
  box-sizing:border-box;
}
input.ok{
  background-color:#afa;
}
#log{
  display:flex;
}
#log label{
  padding:12px;
  font-size:24px;
  color:#aaa;
}
h1{
  font-size:48px;
  font-weight:bold;
  text-align:center;
  padding-bottom:20px;
}
p{
  padding:12px;
  text-align:center;
}