sunburst rendering issue

<!DOCTYPE html>
<meta charset="utf-8">
<style>
path {
  stroke: #fff;
}
</style>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var width = 960,
    height = 700,
    radius = (Math.min(width, height) / 2) - 10;

var formatNumber = d3.format(",d");

var x = d3.scaleLinear()
    .range([0, 2 * Math.PI]);

var y = d3.scaleSqrt()
    .range([0, radius]);

var color = d3.scaleOrdinal(d3.schemeCategory20);

var partition = d3.partition();

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height)
  .append("g")
    .attr("transform", "translate(" + width / 2 + "," + (height / 2) + ")");

d3.json("burst_data.json", function(error, root) {
  if (error) throw error;
  
  root = d3.hierarchy(root);
  root.sum(function(d) { return d.size; });
  svg.selectAll("path")
      .data(partition(root).descendants())
    .enter().append("path")
      .attr("d", arc)
      .style("fill", function(d) { return color((d.children ? d : d.parent).data.name); })
      .on("click", click)
    .append("title")
      .text(function(d) { return d.data.name + "\n" + formatNumber(d.value); });
});

d3.select(self.frameElement).style("height", height + "px");
</script>

LICENSE
#
Released under the GNU General Public License, version 3.

https://d3js.org/d3.v4.min.js