the column counters

add to the bottom of squares():

  var s3="<div class='count bottom' id='n";
  document.write("<div class='row'>");
  for (var c=0;c<10;c++) {
    document.write(s3+n+s4);
    n++;
  }
  document.write('</div>');

and to styles.css:

.bottom {
  margin-top:.1vmin;
  align-items:center;
  width:7.65vmin;
  justify-content:center;
}

This pictures shows the id's that I've assigned to the counters.

See how far you can get with the function do_counters().