body{
  margin:0;
  background:#111;
  overflow:hidden;
  font-family:sans-serif;
  color:white;
}

canvas{ display:block; }

.menu{
  position:fixed;
  inset:0;
  display:flex;
  flex-direction:column;
  justify-content:center;
  align-items:center;
  background:#000c;
}

.hud{
  position:fixed;
  top:10px;
  left:10px;
}

.hidden{ display:none; }

button{
  margin:10px;
  padding:10px 16px;
  font-size:16px;
}