    @keyframes movedash {
        to {
          stroke-dashoffset: 250%;
        }
      }
    </style>
  </head>

  <body>
    <div id="root">
      <svg width="40" height="40" viewbox="0 0 40 40" class="loading-svg">
        <polygon points="0 0 0 40 40 40 40 0" class="loading-rect" />
      </svg>  
    </div>
    <script>
      var mountNode = document.getElementById('root')
      setTimeout(()=>{
        var svg = document.querySelector('.loading-svg')
        if(svg) svg.style.display = 'block'
     