<html>
  <head>
    <style>
      body { margin: 0px; }
      div  {
        margin-top:  0.5px;
        margin-left: 0.5px;
        height: 100px;
        width:  100px;
        background: black;
      }
    </style>
  </head>
  <body><div></div></body>
</html>