<style type="text/css">

body 
{
 display: flex;
 align-items: center;
 justify-content: center;
}

.p5Canvas
{ 
 z-index:20;
 position: absolute;
 max-height: 100%;
 max-width: 100%;
 object-fit: contain;
 top: 50%;left: 50%;
 transform: translate(-50%, -50%);
}
  
.css_background
{
 top: 0px;left: 0px;  width:100%; height:100%;
 z-index:11; border-width:0px; position: fixed;
}

</style>