main{
    font-size: 100px;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
  
    /* perspective & perspective-origin */
    perspective: 10em;
    perspective-origin: 10% calc(50% - 3em);
  
  }

  body{
    background-color: black;
  }
  
  .scene{
    position: relative;
    /**** transform-style: ****/
    transform-style: preserve-3d;
  
    animation: rotate 40s linear infinite;
  
  }
  
  .floor{
    width: 15em;
    height: 15em;
    position: absolute;
    top: 1.02em;
    background-image: 
      radial-gradient(rgb(32 32 32 /.75) 10%,rgb(32 32 32 /.05) 20%, rgb(32 32 32 / 1) 60%),
      repeating-conic-gradient(from 45deg, rgba(18, 183, 65, 0.5) 0deg 90deg, rgb(64 64 64 /.5) 90deg 180deg);
    background-size: 100%, 1em 1em;
    transform: translate(-50%, -50%) rotateX(90deg);
  
    /* animation: rotate 12s infinite linear reverse; */
  
  }
  
  .square{
    position: absolute;
    width: 6em;
    height: 6em;
    /* transform-style */
    transform-style: preserve-3d;
    /* top & left -1em */
    top: -2em;
    left: -2em;
  
    /* transform: translate(-50%, -50%); */
  
    /* animation: rotate 5s linear infinite; */
    animation: rotate 9s linear infinite;
    
  
  }
  
  .center{
    position: absolute; 
    width: 0.25em;
    height: 0.25em;
    border-radius: 50%;
    background-color: rgb(0, 255, 72);
    /* move center of center to center of scene */
    transform: translate(-50%, -50%);
  }
  
  .front, .back, .left, .right{
    position: absolute;
    width: 100%;
    height: 100%;
    background-color: rgba(5, 255, 42, 0.5);
     box-shadow: inset 0 0 0.5em 0 rgb(12 24 36 / 0.75); 
  }
  
  /* transform: rotateY(180deg) translateZ(1em); */
  .front{
    transform: translateZ(1em);
   
  }
  
  .back{
    transform: rotateY(180deg) translateZ(1em);
  }
  
  .right{
    transform: rotateY(90deg) translateZ(1em);
  }
  
  
  .square{
    position: absolute;
    width: 4em;
    height: 4em;
    border-radius: 50%;
    left: -.5em;
    bottom: 1em;
    /* background-image: radial-gradient(triangle at top, rgb(33 66 99 / 0.9), rgb(0 33 66 / 1));
    animation: rotate 30s linear infinite reverse; */
  }
  
  /** @keyframe animations */
  
  /* @keyframes rotate{
    0%{
      transform: rotateX(0deg);
    }
    100%{
      transform: rotateX(360deg);
    }
  } */
  
   @keyframes rotate{
    0%{
      transform: rotateY(0deg);
    }
    100%{
      transform: rotateY(360deg);
    }
  } 
  
  /* @keyframes rotate{
    0%{
      transform: rotateZ(0deg);
    }
    100%{
      transform: rotateX(360deg);
    }
  } */