Make d3 responsive

<!DOCTYPE html>
<head>
  <title>Make D3 Responsive</title>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
/*     body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; } */
    .chart {
      background: lightgray;
      border: 1px solid black;
      /* width: 425px;
      height: 625px;*/
    }
  </style>
</head>

<body>
  <div class="chart"></div>
  <script>
		var margin = {top: 10, right: 25, bottom: 35, left: 40 }
		var width = 425 - margin.left - margin.right
    var height = 625 - margin.top - margin.bottom
    var svg = d3.select('.chart')
    	.append('svg')
    		.attr('width', width + margin.left + margin.right)
    		.attr('height', height + margin.top + margin.bottom)
    		.call(responsivefy)
    	.append('g')
    		.attr('transform', `translate(${margin.left}, ${margin.top})`)
    
    svg.append('rect')
    	.attr('width', width)
    	.attr('height', height)
    	.attr('fill', 'lightblue')
    	.attr('stroke', 'lightgreen')
    
    // draw xAxis
    var xScale = d3.scaleTime()
    	.domain([new Date(2017,8,21,9,0), new Date(2017,8,21,10,0)])
    	.range([0, width])
    var xAxis = d3.axisBottom(xScale)
    	.ticks(5)
    	.tickSize(10)
    	.tickPadding(5)
    svg.append('g')
    	.attr('transform', `translate(${0}, ${height})`)
    	.call(xAxis)
    
    // draw yAxis
    var yScale = d3.scaleLinear()
    	.domain([0, 100])
    	.range([height, 0])
    var yAxis = d3.axisLeft(yScale)
    	.ticks(10)
    	.tickSize(10)
    	.tickPadding(10)
    svg.append('g')
    	.attr('transform', `transform(${margin.left}, ${margin.top})`)
			.call(yAxis)
    	
    
    function responsivefy(svg) {
      // get container + svg aspect ratio
      var container = d3.select(svg.node().parentNode),
          width = parseInt(svg.style("width")),
          height = parseInt(svg.style("height")),
          aspect = width / height;

// add viewBox and preserveAspectRatio properties,
      // and call resize so that svg resizes on inital page load
      svg.attr("viewBox", "0 0 " + width + " " + height)
          .attr("preserveAspectRatio", "xMinYMid")
          .call(resize);

// to register multiple listeners for same event type,
      // you need to add namespace, i.e., 'click.foo'
      // necessary if you call invoke this function for multiple svgs
      // api docs: https://github.com/mbostock/d3/wiki/Selections#on
      d3.select(window).on("resize." + container.attr("id"), resize);

// get width of container and resize svg to fit it
      function resize() {
          var targetWidth = parseInt(container.style("width"));
          svg.attr("width", targetWidth);
          svg.attr("height", Math.round(targetWidth / aspect));
      }
    }
  </script>
</body>

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