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CSS

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HTML 

              
                <main class="container">
  <h1 id="title">United States Educational Attainment</h1>
  <h2 id="description">Percentage of adults age 25 and older <br/> with a bachelor's degree or higher (2010-2014)</h2>
  <div id="map"></div>
</main>
!

CSS 

              
                @import url('https://fonts.googleapis.com/css2?family=Open+Sans&display=swap');
@import url('https://fonts.googleapis.com/css2?family=Newsreader&display=swap');

* {
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Open Sans', sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
  height: 100vh;
  background: gainsboro;
}

h1 {
  font-family: 'Newsreader', serif;
  font-size: 3rem;
  margin-bottom: 25px;
}

h2 {
  font-size: 0.8rem;
  align-self: flex-end;
  margin-right: 105px;
}

.container {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

.county:hover {
  fill: tomato;
}

#tooltip {
  position: absolute;
  font-size: 0.8rem;
  color: gainsboro;
  width: auto;
  height: auto;
  padding: 8px;
  background: #101E3A;
  border-radius: 6px;
}

@media screen and (max-width: 950px) {
  .container {
    transform: scale(0.9);
  }
}
@media screen and (max-width: 850px) {
  .container {
    transform: scale(0.8);
  }
}
@media screen and (max-width: 750px) {
  .container {
    transform: scale(0.7);
  }
}
@media screen and (max-width: 650px) {
  .container {
    transform: scale(0.6);
  }
}
@media screen and (max-width: 550px) {
  .container {
    transform: scale(0.5);
  }
}
@media screen and (max-width: 450px) {
  .container {
    transform: scale(0.4);
  }
}
@media screen and (max-width: 350px) {
  .container {
    transform: scale(0.3);
  }
}
!

JS 

              
                document.addEventListener('DOMContentLoaded', () => {

  const colors = [
    '#427EF5', '#3B70DA', '#3463C0', '#2D55A5', '#25478A', '#1E396F', '#172C55', '#101E3A'
  ];  

  const colorData = (percentage) => {
    if (percentage >= 0 && percentage < 10) { return colors[0] }
    else if (percentage >= 10 && percentage < 20) { return colors[1] }
    else if (percentage >= 20 && percentage < 30) { return colors[2] }
    else if (percentage >= 30 && percentage < 40) { return colors[3] }
    else if (percentage >= 40 && percentage < 50) { return colors[4] }
    else if (percentage >= 50 && percentage < 60) { return colors[5] }
    else if (percentage >= 60 && percentage < 70) { return colors[6] }
    else if (percentage >= 70 && percentage < 80) { return colors[7] }
  }

  const width = 950;
  const height = 600;

  const map = d3.select('#map')
                .append('svg')
                .attr('width', width)
                .attr('height', height);

  const legendData = [0, 10, 20, 30, 40, 50, 60, 70]; 
  const legendCellWidth = 40;             

  const legend = map.append('svg')
                    .attr('x', width - (80 + legendCellWidth * legendData.length))
                    .attr('y', 20)
                    .attr('width', legendCellWidth * legendData.length)
                    .attr('height', 100)
                    .attr('id', 'legend');  
                    
  legend.selectAll('.legend')
        .data(legendData)
        .enter()
        .append('rect')
        .attr('x', (d, i) => (legendCellWidth * i))
        .attr('y', 0)
        .attr('width', legendCellWidth)
        .attr('height', 10)
        .style('fill', (d) => colorData(d));   
        
  legend.selectAll('.text')
        .data(legendData)
        .enter()
        .append('text')
        .text((d) => d.toString() + '%')
        .attr('x', (d, i) => legendCellWidth * i)
        .attr('y', 25)
        .style('font-size', 12 + 'px')

  const tooltip = d3.select('#map')
                    .append('div')
                    .attr('id', 'tooltip')
                    .style('opacity', 0);  

  const mouseover = (event, d) => {
    const [x, y] = d3.pointer(event);
    tooltip.style('opacity', 0.9)
           .style('left', x + 'px')
           .style('top', y + 'px'); 
    let id = d.id;
    let county = educationData.find((item) => {
      return item['fips'] === id;
    });
    tooltip.attr('data-education', county['bachelorsOrHigher']);
    tooltip.html(
      county['area_name'] + ', ' + county['state'] + ': ' +
      county['bachelorsOrHigher'] + '%'
    );
  }                    

  const mouseout = () => {
    tooltip.style('opacity', 0);
  }

  const drawMap = () => {
    map.selectAll('path')
       .data(countyData)
       .enter()
       .append('path')
       .attr('d', d3.geoPath())
       .attr('class', 'county')
       .attr('data-fips', (d) => d.id)
       .attr('data-education', (d) => {
          let id = d.id;
          let county = educationData.find((item) => {
            return item['fips'] === id;
          })
          let percentage = county['bachelorsOrHigher'];
          return percentage;
        })
       .attr('fill', (d) => {
         let id = d.id;
         let county = educationData.find((item) => {
           return item['fips'] === id;
         });
         let percentage = county['bachelorsOrHigher'];
         if (percentage >= 0 && percentage < 10) { return colors[0] }
         else if (percentage >= 10 && percentage < 20) { return colors[1] }
         else if (percentage >= 20 && percentage < 30) { return colors[2] }
         else if (percentage >= 30 && percentage < 40) { return colors[3] }
         else if (percentage >= 40 && percentage < 50) { return colors[4] }
         else if (percentage >= 50 && percentage < 60) { return colors[5] }
         else if (percentage >= 60 && percentage < 70) { return colors[6] }
         else if (percentage >= 70 && percentage < 80) { return colors[7] } 
       })
       .on('mouseover', mouseover)
       .on('mouseout', mouseout);    
       
    map.append('path')
       .classed('stateBorder', true)
       .attr('fill', 'none')
       .attr('stroke', 'gainsboro')
       .attr('stroke-width', 0.75)
       .datum(stateData, (a, b) => a !== b)
       .attr('d', d3.geoPath());
  }

  const countyURL = 'https://cdn.freecodecamp.org/testable-projects-fcc/data/choropleth_map/counties.json';
  const educationURL = 'https://cdn.freecodecamp.org/testable-projects-fcc/data/choropleth_map/for_user_education.json';

  let countyData;
  let stateData;
  let educationData;

  d3.json(countyURL).then(
    (data, error) => {
      if (error) {
        console.log(error); 
      } else {
        countyData = topojson.feature(data, data.objects.counties).features; 
        stateData = topojson.mesh(data, data.objects.states); 
        // console.log(countyData);
        d3.json(educationURL).then(
          (data, error) => {
            if (error) {
              console.log(error); 
            } else {
              educationData = data;
              // console.log(data);
              // console.log(d3.min(data, (d) => d.bachelorsOrHigher));
              // console.log(d3.max(data, (d) => d.bachelorsOrHigher));
              drawMap();
            }
          }
        );
      }
    }
  );

});
!
999px

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