Collapsible Animated Indented Tree with larger root node

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
    <title>Node-Link Tree</title>
    
	<link href="interactive_tree.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/d3@1.29.5/d3.js"></script>
    <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/d3@1.29.5/d3.layout.js"></script>
 
  </head>
  <body>
    <div id="chart"></div>
    <script type="text/javascript">

var w = 960,
    h = 2000,
    i = 0,
    duration = 500,
    root;

var tree = d3.layout.tree()
    .size([h, w - 160]);

var diagonal = d3.svg.diagonal()
    .projection(function(d) { return [d.y, d.x]; });

var vis = d3.select("#chart").append("svg:svg")
    .attr("width", w)
    .attr("height", h)
  .append("svg:g")
    .attr("transform", "translate(40,0)");

d3.json("math_map_compact.json", function(json) {
  json.x0 = 800;
  json.y0 = 0;
  update(root = json);
});

function update(source) {

// Compute the new tree layout.
  var nodes = tree.nodes(root).reverse();
 console.log(nodes)
  // Update the nodes…
  	var node = vis.selectAll("g.node")
      .data(nodes, function(d) { return d.id || (d.id = ++i); });

// Transition nodes to their new position.
	nodeEnter.transition()
		.duration(duration)
		.attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })
      	.style("opacity", 1)
      .select("circle")
    	//.attr("cx", function(d) { return d.x; })
		//.attr("cy", function(d) { return d.y; })
        .style("fill", "lightsteelblue");
      
    node.transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })
      .style("opacity", 1);

node.exit().transition()
      .duration(duration)
      .attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
      .style("opacity", 1e-6)
      .remove();
/*
	var nodeTransition = node.transition()
		.duration(duration);
  
  nodeTransition.select("circle")
      .attr("cx", function(d) { return d.y; })
      .attr("cy", function(d) { return d.x; })
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });
  
  nodeTransition.select("text")
      .attr("dx", function(d) { return d._children ? -8 : 8; })
	  .attr("dy", 3)
      .style("fill", function(d) { return d._children ? "lightsteelblue" : "#5babfc"; });

// Transition exiting nodes to the parent's new position.
  var nodeExit = node.exit();
  
  nodeExit.select("circle").transition()
      .duration(duration)
      .attr("cx", function(d) { return source.y; })
      .attr("cy", function(d) { return source.x; })
      .remove();
  
  nodeExit.select("text").transition()
      .duration(duration)
      .remove();
*/
  // Update the links…
  var link = vis.selectAll("path.link")
      .data(tree.links(nodes), function(d) { return d.target.id; });

// Enter any new links at the parent's previous position.
  link.enter().insert("svg:path", "g")
      .attr("class", "link")
      .attr("d", function(d) {
        var o = {x: source.x0, y: source.y0};
        return diagonal({source: o, target: o});
      })
    .transition()
      .duration(duration)
      .attr("d", diagonal);

// Transition links to their new position.
  link.transition()
      .duration(duration)
      .attr("d", diagonal);

// Transition exiting nodes to the parent's new position.
  link.exit().transition()
      .duration(duration)
      .attr("d", function(d) {
        var o = {x: source.x, y: source.y};
        return diagonal({source: o, target: o});
      })
      .remove();

// Stash the old positions for transition.
  nodes.forEach(function(d) {
    d.x0 = d.x;
    d.y0 = d.y;
  });
}

// Toggle children on click.
function click(d) {
  if (d.children) {
    d._children = d.children;
    d.children = null;
  } else {
    d.children = d._children;
    d._children = null;
  }
  update(d);
}

d3.select(self.frameElement).style("height", "2000px");

</script>
  </body>
</html>

Modified http://mbostock.github.com/d3/d3.js?1.27.2 to a secure url

Modified http://mbostock.github.com/d3/d3.layout.js?1.27.2 to a secure url

https://mbostock.github.com/d3/d3.js?1.27.2

https://mbostock.github.com/d3/d3.layout.js?1.27.2