--description--

It's possible to add effects that highlight a bar when the user hovers over it with the mouse. So far, the styling for the rectangles is applied with the built-in D3 and SVG methods, but you can use CSS as well.

You set the CSS class on the SVG elements with the attr() method. Then the :hover pseudo-class for your new class holds the style rules for any hover effects.

--instructions--

Use the attr() method to add a class of bar to all the rect elements. This changes the fill color of the bar to brown when you mouse over it.

--hints--

Your rect elements should have a class of bar.

assert.isTrue(document.querySelector('rect')?.classList.contains('bar'));

--seed--

--seed-contents--

html

<style>
  .bar:hover {
    fill: brown;
  }
</style>
<body>
  <script>
    const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];

    const w = 500;
    const h = 100;

    const svg = d3
      .select('body')
      .append('svg')
      .attr('width', w)
      .attr('height', h);

    svg
      .selectAll('rect')
      .data(dataset)
      .enter()
      .append('rect')
      .attr('x', (d, i) => i * 30)
      .attr('y', (d, i) => h - 3 * d)
      .attr('width', 25)
      .attr('height', (d, i) => 3 * d)
      .attr('fill', 'navy');
    // Add your code below this line



    // Add your code above this line

    svg
      .selectAll('text')
      .data(dataset)
      .enter()
      .append('text')
      .text(d => d)
      .attr('x', (d, i) => i * 30)
      .attr('y', (d, i) => h - 3 * d - 3);
  </script>
</body>

--solutions--