var DEFAULT_OPTIONS = {
  margin: {top: 0, right: 0, bottom: 0, left: 0}
};

var chart = new d3Kit.Skeleton('.chart', DEFAULT_OPTIONS)
  .autoResize('both')
  .autoResizeToAspectRatio(3/2);

var rect = chart.getRootG()
  .append('rect')
  .style('fill', '#fff');

var circle = chart.getRootG()
  .append('circle')
  .attr('fill', 'red');

chart.on('resize', function() {
  var width = chart.getInnerWidth();
  var height = chart.getInnerHeight();

  rect
    .transition()
    .duration(1000)
    .attr('width', width)
    .attr('height', height);

  circle
    .transition()
    .duration(1000)
    .attr('cx', width / 2)
    .attr('cy', height / 2)
    .attr('r', 3/5/2 * chart.height());
});