body {  
    background: white;
    padding: 10px;
    background-image: url('https://geoportal.vizugy.hu/vizmercek_honlap/graphics/OVF_logo_halvany.png');
    background-size: contain;
    background-position: center;
    background-repeat: no-repeat;
  }
  
  canvas {
    border: 0px dotted red;
    max-height: calc(100vh - 40px);
  }
  
  .chart-container {
    position: absolute;
    margin: auto;
    height: 100vh;
    width: 80vw;
  }

  .myDIV {
    display: none;
  }
  
  .slider {
    position: absolute;
    left: 340px;
    width: 400px;
    height: 25px;
  }
  
  .slider:hover {
    opacity: 1;
  }