bubble chart with viewbox

This is an update to the Mike's version by introducing bootstrap and viewbox concept for responsive charts.

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
      <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.slim.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
       .border {
        border: 1px solid black;
    }
    svg {
        font-family: sans-serif;
        font-size: 10px;
        text-anchor: middle;
    }
  </style>
</head>

</div>
            </div>
            <div class="border col-md-4">
                <div class="bubble-chart"></div>
            </div>
        </div>
        <div class="row">
            <div class="border col-md-6">
                <div class="bubble-chart"></div>
            </div>
            <div class="border col-md-6">
                <div class="bubble-chart"></div>
            </div>
        </div>
    </div>
    <script>
        var margin = { top:10, right:10, bottom: 10, left:10},
            width = 960,
            height = 960,
            svg = d3.selectAll('.bubble-chart').append('svg')
                    .attr('width', '100%')
                    .attr('height', '100%')
                    .attr('viewBox', '-' + (margin.left + margin.right) + ' ' + (margin.bottom) + ' ' + width + ' ' + height)
                    .attr('preserveAspectRatio', 'xMinYMin meet');
        width = width - margin.left - margin.right;
        height = height - margin.top - margin.bottom;

var format = d3.format(',d');

var color = d3.scaleOrdinal(d3.schemeCategory20c);

var pack = d3.pack()
            .size([width, height])
            .padding(1.5);
        
        d3.csv('./flare.csv', function(d){
            d.value = +d.value;
            if (d.value) return d;
        }, function(error, classes){
            if (error) throw error;

https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.slim.min.js

https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js

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