html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  background:#000;
}

#fixed-bg {
  position: fixed;
  left:50%;
  top:50%;
  transform:translate(-50%, -50%);
  width:100vw;
  height:100vh;
}

canvas {
  position: absolute;
  top:50%;
  left:50%;
  transform:translate(-50%, -50%);  
  aspect-ratio: 1;
}

#c {
  width: auto;
  height: 100%;
}

#c2 {
  width: 100%;
  height: auto;
}

@media (max-aspect-ratio: 1) {
  #c {
    width: 100%;
    height: auto;
  }
  
  #c2 {
    width: auto;
    height: 100%;
  }
}