html,body,main{
    background-color: rgb(22, 22, 23);
}
.cube {
    position: relative;
    width: 300px;
    height: 300px;
    transform-style: preserve-3d;
    transform: rotateX(-30deg);
    animation: animateD 8s linear infinite;
  }
  
  @keyframes animateD {
    0% {
      transform: rotateX(-15deg) rotateY(0deg);
    }
  
    100% {
      transform: rotateX(-15deg) rotateY(-360deg);
    }
  }
  
  .cube div {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
  }
  
  .cube2 {
    position: relative;
    width: 150px;
    height: 150px;
    transform-style: preserve-3d;
    animation: animateD2 5s ease-out infinite alternate;
  }
  
  @keyframes animateD2 {
    0% {
      transform: rotateX(0deg) rotateY(0deg);
    }
  
    100% {
      transform: rotateX(180deg) rotateY(-360deg);
    }
  }
  
  .cube2 div {
    position: absolute;
    top: 35px;
    left: 0;
    width: 65%;
    height: 65%;
    transform-style: preserve-3d;
  }
  
  .cube2 div span {
    position: absolute;
    top: 20%;
    left: 20%;
    width: 65%;
    height: 65%;
    background: transparent;
    border: 2px solid #7dff99;
    transform: rotateY(calc(90deg * var(--i))) translateZ(62px);
  }
  
  .cube3 {
    position: absolute;
    width: 300px;
    height: 300px;
    transform-style: preserve-3d;
    transform: rotateX(-30deg);
    animation: animateD3 1s ease-in-out infinite alternate;
  }
  
  @keyframes animateD3 {
    0% {
      transform: rotateX(-90deg) rotateY(0deg);
    }
  
    100% {
      transform: rotateX(90deg) rotateY(45deg);
    }
  }
  
  .cube3 div {
    position: absolute;
    top: 70px;
    left: 70px;
    width: 15%;
    height: 15%;
    transform-style: preserve-3d;
  }
  
  .cube3 div span {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #7dff99;
    transform: rotateY(calc(90deg * var(--i))) translateZ(14px);
    box-shadow: 0px 0px 7px #7dff99;
  }
  
  .top3 {
    position: absolute;
    top: 0;
    left: 0;
    background: #7dff99;
    transform: rotateX(90deg) translateZ(14px);
    box-shadow: 0px 0px 10px #7dff99;
  }
  
  .--main{
    transform: translate(-50%,-50%);
  }