JSFiddle - React, Tailwind, and code Playground

CSS

svg {
  font: 10px sans-serif;
}

path {
  fill: steelblue;
}

.axis path,
.axis line {
  fill: none;
  stroke: #000;
  shape-rendering: crispEdges;
}

.brush .extent {
  stroke: #fff;
  fill-opacity: .125;
  shape-rendering: crispEdges;
}

JavaScript

var margin = {top: 10, right: 10, bottom: 100, left: 40},
    margin2 = {top: 430, right: 10, bottom: 20, left: 40},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom,
    height2 = 500 - margin2.top - margin2.bottom;

var data = [{
    'Wed Jan 23 00:00:00 IST 2013': 3383387
}, {
    'Thu Jan 24 00:00:00 IST 2013': 3883387
}, {
    'Fri Jan 25 00:00:00 IST 2013': 4383387
}, {
    'Sat Jan 26 00:00:00 IST 2013': 2383387
}, {
    'Sun Jan 27 00:00:00 IST 2013': 5383387
}, {
    'Mon Jan 28 00:00:00 IST 2013': 2283387
}];

var format = d3.time.format("%a %b %d %H:%M:%S IST %Y");

var parseDate = d3.time.format("%b %Y").parse;

var x = d3.time.scale().range([0, width]),
    x2 = d3.time.scale().range([0, width]),
    y = d3.scale.linear().range([height, 0]),
    y2 = d3.scale.linear().range([height2, 0]);

var xAxis = d3.svg.axis().scale(x).orient("bottom"),
    xAxis2 = d3.svg.axis().scale(x2).orient("bottom"),
    yAxis = d3.svg.axis().scale(y).orient("left");

var brush = d3.svg.brush()
    .x(x2)
    .on("brush", brush);

var area = d3.svg.area()
    .interpolate("monotone")
    .x(function(d) { return x(format.parse(d3.keys(d)[0])); })
    .y0(height)
    .y1(function(d) { return y(d3.values(d)[0]); });

var area2 = d3.svg.area()
    .interpolate("monotone")
    .x(function(d) { return x2(format.parse(d3.keys(d)[0])); })
    .y0(height2)
    .y1(function(d) { return y2(d3.values(d)[0]); });

var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom);

svg.append("defs").append("clipPath")
    .attr("id", "clip")
  .append("rect")
    .attr("width", width)
    .attr("height", height);

var focus = svg.append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var context = svg.append("g")
    .attr("transform", "translate(" + margin2.left + "," + margin2.top + ")");

 ...