JSFiddle - React, Tailwind, and code Playground

HTML

<div id="leftsidebar"></div> 
   <div id="main">
      <div id="chart">
        <div id="explanation" style="visibility: hidden;">
          <span id="percentage"></span><br/>
          of visits begin with this sequence of pages
        </div>
      </div>
    </div>
    <div id="sidebar">
      <input type="checkbox" id="togglelegend"> Legend<br/>
      <div id="legend" style="visibility: hidden;"></div>
    </div>

CSS

body {
  font-family: 'Open Sans', sans-serif;
  font-size: 12px;
  font-weight: 400;
  background-color: #fff;
  width: 780px;
  height: 800px;
  margin-top: 10px;
}

#main {
  float: left;
  width: 550px;
}

#sidebar {
  float: right;
  width: 100px;
}

#leftsidebar {
  float: left;
  width: 100px;
    height: 600px;
}

#sequence {
  width: 600px;
  height: 70px;
}

#legend {
  padding: 10px 0 0 3px;
}

#sequence text, #legend text {
  font-weight: 600;
  fill: #fff;
}

#chart {
  position: relative;
}

#chart path {
  stroke: #fff;
}

#explanation {
  position: absolute;
  top: 235px;
  left: 205px;
  width: 140px;
  text-align: center;
  color: #666;
  z-index: 0;
}

#percentage {
  font-size: 2.5em;
}

JavaScript

// Dimensions of sunburst.
var width = 550;
var height = 550;
var radius = Math.min(width, height) / 2;

// Breadcrumb dimensions: width, height, spacing, width of tip/tail.
var b = {
    w: 75, h: 30, s: 3, t: 10
};

// make `colors` an ordinal scale
var colors = d3.scale.category20();

// Total size of all segments; we set this later, after loading the data.
var totalSize = 0; 

var vis = d3.select("#chart").append("svg:svg")
    .attr("width", width)
    .attr("height", height)
    .append("svg:g")
    .attr("id", "container")
    .attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");

var partition = d3.layout.partition()
    .size([2 * Math.PI, 100])
    .value(function(d) { return d.size; });

var arc = d3.svg.arc()
    .startAngle(function(d) { return d.x; })
    .endAngle(function(d) { return d.x + d.dx; })
    .innerRadius(function(d) { return radius * Math.sqrt(d.y) / 10; })
    .outerRadius(function(d) { return radius * Math.sqrt(d.y + d.dy) / 10; });

var json = getData();
createVisualization(json);

// Main function to draw and set up the visualization, once we have the data.
function createVisualization(json) {

    // Basic setup of page elements.
    initializeBreadcrumbTrail();
  
    d3.select("#togglelegend").on("click", toggleLegend);

    // Bounding circle underneath the sunburst, to make it easier to detect
    // when the mouse leaves the parent g.
    vis.append("svg:circle")
        .attr("r", radius)
        .style("opacity", 0);

    // For efficiency, filter nodes to keep only those large enough to see.
    var nodes = partition.nodes(json)
        .filter(function(d) {
            return (d.dx > 0.005); // 0.005 radians = 0.29 degrees
        });
    
    var uniqueNames = (function(a) {
        var output = [];
        a.forEach(function(d) {
            if (output.indexOf(d.name) === -1) {
                output.push(d.name);
            }
        });
        return output;
    })(nodes);
    
    // set domain of...