In a Highcharts pie chart, how can I round off the boundaries in a series?

Question

In a Highcharts pie chart, how can I round off the boundaries in a series?

I am trying to recreate this image using Highcharts 5 (style) and am struggling to figure out a way to round the borders. Setting the property border-radius

with css has no effect. The solution must also support more than two data points, but this is not shown in the image.

I found a similar question, but it doesn't show how to work with multiple data points: How to make a pie chart with a data border radius in highchart

Any ideas?

var random = function(top) {
  if (!top) {
    top = 1000;
  }
  return Math.floor(Math.random() * top);
};

var chart = Highcharts.chart('chart', {
  chart: {
    type: 'pie',
    margin: 5
  },
  plotOptions: {
    pie: {
      slicedOffset: 0,
      size: '100%',
      dataLabels: {
        enabled: false
      },
      states: {
        hover: {
          enabled: false
        }
      }
    }
  },

  series: [{
    type: 'pie',
    size: '100%',
    innerSize: '85%',
    allowPointSelect: false,
    className: 'pizza',
    data: [{
      name: 'Name 1',
      className: 'customSeries1'
    }, {
      name: 'Name 2',
      className: 'customSeries2'
    }],
    showInLegend: false
  }],

  tooltip: {
    useHTML: true,
    borderRadius: 0,
    borderWidth: 1,
    shadow: false,
    shape: 'square',
    style: {
      padding: 8
    }
  },
  title: null,
  credits: {
    enabled: false
  },
  exporting: {
    enabled: false
  },
}, loadChartData);

function loadChartData(chart) {
  if (!chart.renderer.forExport) {
    chart.series[0].points[0].update(random(5000000));
    chart.series[0].points[1].update(random(5000000));
  }
};

/**
 * @license Highcharts
 *
 * (c) 2009-2016 Torstein Honsi
 *
 * License: www.highcharts.com/license
 */

.highcharts-container {
  position: relative;
  overflow: hidden;
  width: 100%;
  height: 100%;
  text-align: left;
  line-height: normal;
  z-index: 0;
  /* #1072 */
  -webkit-tap-highlight-color: transparent;
  font-family: "Lucida Grande", "Lucida Sans Unicode", Arial, Helvetica, sans-serif;
  font-size: 12px;
}

.highcharts-root text {
  stroke-width: 0;
}

.highcharts-strong {
  font-weight: bold;
}

.highcharts-emphasized {
  font-style: italic;
}

.highcharts-background {
  fill: #ffffff;
}

.highcharts-plot-border,
.highcharts-plot-background {
  fill: none;
}

.highcharts-label-box {
  fill: none;
}

.highcharts-button-box {
  fill: inherit;
}


/* Titles */

.highcharts-title {
  fill: #333333;
  font-size: 1.5em;
}

.highcharts-subtitle {
  fill: #666666;
}


/* Axes */

.highcharts-axis-line {
  fill: none;
  stroke: #ccd6eb;
}

.highcharts-yaxis .highcharts-axis-line {
  stroke-width: 0;
}

.highcharts-axis-title {
  fill: #666666;
}

.highcharts-axis-labels {
  fill: #666666;
  cursor: default;
  font-size: 0.9em;
}

.highcharts-grid-line {
  fill: none;
  stroke: #e6e6e6;
}

.highcharts-xaxis-grid .highcharts-grid-line {
  stroke-width: 0;
}

.highcharts-tick {
  stroke: #ccd6eb;
}

.highcharts-yaxis .highcharts-tick {
  stroke-width: 0;
}

.highcharts-minor-grid-line {
  stroke: #f2f2f2;
}

.highcharts-crosshair-thin {
  stroke-width: 1px;
  stroke: #cccccc;
}

.highcharts-crosshair-category {
  stroke: #ccd6eb;
  stroke-opacity: 0.25;
}


/* Credits */

.highcharts-credits {
  cursor: pointer;
  fill: #999999;
  font-size: 0.7em;
  transition: fill 250ms, font-size 250ms;
}

.highcharts-credits:hover {
  fill: black;
  font-size: 1em;
}


/* Tooltip */

.highcharts-tooltip {
  cursor: default;
  pointer-events: none;
  white-space: nowrap;
  transition: stroke 150ms;
}

.highcharts-tooltip text {
  fill: #333333;
}

.highcharts-tooltip .highcharts-header {
  font-size: 0.85em;
}

.highcharts-tooltip-box {
  stroke-width: 1px;
  fill: #f7f7f7;
  fill-opacity: 0.85;
}

.highcharts-selection-marker {
  fill: #335cad;
  fill-opacity: 0.25;
}

.highcharts-graph {
  fill: none;
  stroke-width: 2px;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.highcharts-state-hover .highcharts-graph {
  stroke-width: 3;
}

.highcharts-state-hover path {
  transition: stroke-width 50;
  /* quick in */
}

.highcharts-state-normal path {
  transition: stroke-width 250ms;
  /* slow out */
}


/* Legend hover affects points and series */

g.highcharts-series,
.highcharts-point,
.highcharts-markers,
.highcharts-data-labels {
  transition: opacity 250ms;
}

.highcharts-legend-series-active g.highcharts-series:not(.highcharts-series-hover),
.highcharts-legend-point-active .highcharts-point:not(.highcharts-point-hover),
.highcharts-legend-series-active .highcharts-markers:not(.highcharts-series-hover),
.highcharts-legend-series-active .highcharts-data-labels:not(.highcharts-series-hover) {
  opacity: 0.2;
}


/* Series options */


/* Default colors */

.highcharts-color-0 {
  fill: #7cb5ec;
  stroke: #7cb5ec;
}

.highcharts-color-1 {
  fill: #434348;
  stroke: #434348;
}

.highcharts-color-2 {
  fill: #90ed7d;
  stroke: #90ed7d;
}

.highcharts-color-3 {
  fill: #f7a35c;
  stroke: #f7a35c;
}

.highcharts-color-4 {
  fill: #8085e9;
  stroke: #8085e9;
}

.highcharts-color-5 {
  fill: #f15c80;
  stroke: #f15c80;
}

.highcharts-color-6 {
  fill: #e4d354;
  stroke: #e4d354;
}

.highcharts-color-7 {
  fill: #2b908f;
  stroke: #2b908f;
}

.highcharts-color-8 {
  fill: #f45b5b;
  stroke: #f45b5b;
}

.highcharts-color-9 {
  fill: #91e8e1;
  stroke: #91e8e1;
}

.highcharts-area {
  fill-opacity: 0.75;
  stroke-width: 0;
}

.highcharts-markers {
  stroke-width: 1px;
  stroke: #ffffff;
}

.highcharts-point {
  stroke-width: 1px;
}

.highcharts-dense-data .highcharts-point {
  stroke-width: 0;
}

.highcharts-data-label {
  font-size: 0.9em;
  font-weight: bold;
}

.highcharts-data-label-box {
  fill: none;
  stroke-width: 0;
}

.highcharts-data-label text {
  fill: #333333;
}

.highcharts-data-label-connector {
  fill: none;
}

.highcharts-halo {
  fill-opacity: 0.25;
  stroke-width: 0;
}

.highcharts-point-select {
  fill: #cccccc;
  stroke: #000000;
}

.highcharts-column-series rect.highcharts-point {
  stroke: #ffffff;
}

.highcharts-column-series .highcharts-point {
  transition: fill-opacity 250ms;
}

.highcharts-column-series .highcharts-point-hover {
  fill-opacity: 0.75;
  transition: fill-opacity 50ms;
}

.highcharts-pie-series .highcharts-point {
  stroke-linejoin: round;
  stroke: #ffffff;
}

.highcharts-pie-series .highcharts-point-hover {
  fill-opacity: 0.75;
  transition: fill-opacity 50ms;
}

.highcharts-pie-series .highcharts-point-select {
  fill: inherit;
  stroke: inherit;
}

.highcharts-funnel-series .highcharts-point {
  stroke-linejoin: round;
  stroke: #ffffff;
}

.highcharts-funnel-series .highcharts-point-hover {
  fill-opacity: 0.75;
  transition: fill-opacity 50ms;
}

.highcharts-funnel-series .highcharts-point-select {
  fill: inherit;
  stroke: inherit;
}

.highcharts-pyramid-series .highcharts-point {
  stroke-linejoin: round;
  stroke: #ffffff;
}

.highcharts-pyramid-series .highcharts-point-hover {
  fill-opacity: 0.75;
  transition: fill-opacity 50ms;
}

.highcharts-pyramid-series .highcharts-point-select {
  fill: inherit;
  stroke: inherit;
}

.highcharts-solidgauge-series .highcharts-point {
  stroke-width: 0;
}

.highcharts-treemap-series .highcharts-point {
  stroke-width: 1px;
  stroke: #e6e6e6;
  transition: stroke 250ms, fill 250ms, fill-opacity 250ms;
}

.highcharts-treemap-series .highcharts-point-hover {
  stroke: #999999;
  transition: stroke 25ms, fill 25ms, fill-opacity 25ms;
}

.highcharts-treemap-series .highcharts-above-level {
  display: none;
}

.highcharts-treemap-series .highcharts-internal-node {
  fill: none;
}

.highcharts-treemap-series .highcharts-internal-node-interactive {
  fill-opacity: 0.15;
  cursor: pointer;
}

.highcharts-treemap-series .highcharts-internal-node-interactive:hover {
  fill-opacity: 0.75;
}


/* Legend */

.highcharts-legend-box {
  fill: none;
  stroke-width: 0;
}

.highcharts-legend-item text {
  fill: #333333;
  font-weight: bold;
  cursor: pointer;
  stroke-width: 0;
}

.highcharts-legend-item:hover text {
  fill: #000000;
}

.highcharts-legend-item-hidden * {
  fill: #cccccc !important;
  stroke: #cccccc !important;
  transition: fill 250ms;
}

.highcharts-legend-nav-active {
  fill: #003399;
  cursor: pointer;
}

.highcharts-legend-nav-inactive {
  fill: #cccccc;
}

.highcharts-legend-title-box {
  fill: none;
  stroke-width: 0;
}


/* Loading */

.highcharts-loading {
  position: absolute;
  background-color: #ffffff;
  opacity: 0.5;
  text-align: center;
  z-index: 10;
  transition: opacity 250ms;
}

.highcharts-loading-hidden {
  height: 0 !important;
  opacity: 0;
  overflow: hidden;
  transition: opacity 250ms, height 250ms step-end;
}

.highcharts-loading-inner {
  font-weight: bold;
  position: relative;
  top: 45%;
}


/* Plot bands and polar pane backgrounds */

.highcharts-plot-band,
.highcharts-pane {
  fill: #000000;
  fill-opacity: 0.05;
}

.highcharts-plot-line {
  fill: none;
  stroke: #999999;
  stroke-width: 1px;
}


/* Highcharts More */

.highcharts-boxplot-box {
  fill: #ffffff;
}

.highcharts-boxplot-median {
  stroke-width: 2px;
}

.highcharts-bubble-series .highcharts-point {
  fill-opacity: 0.5;
}

.highcharts-errorbar-series .highcharts-point {
  stroke: #000000;
}

.highcharts-gauge-series .highcharts-data-label-box {
  stroke: #cccccc;
  stroke-width: 1px;
}

.highcharts-gauge-series .highcharts-dial {
  fill: #000000;
  stroke-width: 0;
}

.highcharts-polygon-series .highcharts-graph {
  fill: inherit;
  stroke-width: 0;
}

.highcharts-waterfall-series .highcharts-graph {
  stroke: #333333;
  stroke-dasharray: 1, 3;
}


/* Highstock */

.highcharts-navigator-mask-outside {
  fill-opacity: 0;
}

.highcharts-navigator-mask-inside {
  fill: #6685c2;
  /* navigator.maskFill option */
  fill-opacity: 0.25;
  cursor: ew-resize;
}

.highcharts-navigator-outline {
  stroke: #cccccc;
  fill: none;
}

.highcharts-navigator-handle {
  stroke: #cccccc;
  fill: #f2f2f2;
  cursor: ew-resize;
}

.highcharts-navigator-series {
  fill: #335cad;
  stroke: #335cad;
}

.highcharts-navigator-series .highcharts-graph {
  stroke-width: 1px;
}

.highcharts-navigator-series .highcharts-area {
  fill-opacity: 0.05;
}

.highcharts-navigator-xaxis .highcharts-axis-line {
  stroke-width: 0;
}

.highcharts-navigator-xaxis .highcharts-grid-line {
  stroke-width: 1px;
  stroke: #e6e6e6;
}

.highcharts-navigator-xaxis.highcharts-axis-labels {
  fill: #999999;
}

.highcharts-navigator-yaxis .highcharts-grid-line {
  stroke-width: 0;
}

.highcharts-scrollbar-thumb {
  fill: #cccccc;
  stroke: #cccccc;
  stroke-width: 1px;
}

.highcharts-scrollbar-button {
  fill: #e6e6e6;
  stroke: #cccccc;
  stroke-width: 1px;
}

.highcharts-scrollbar-arrow {
  fill: #666666;
}

.highcharts-scrollbar-rifles {
  stroke: #666666;
  stroke-width: 1px;
}

.highcharts-scrollbar-track {
  fill: #f2f2f2;
  stroke: #f2f2f2;
  stroke-width: 1px;
}

.highcharts-button {
  fill: #f7f7f7;
  stroke: #cccccc;
  cursor: default;
  stroke-width: 1px;
  transition: fill 250ms;
}

.highcharts-button text {
  fill: #333333;
}

.highcharts-button-hover {
  transition: fill 0ms;
  fill: #e6e6e6;
  stroke: #333333;
}

.highcharts-button-pressed {
  font-weight: bold;
  fill: #e6ebf5;
  stroke: #335cad;
}

.highcharts-button-disabled text {
  fill: #cccccc;
}

.highcharts-range-selector-buttons .highcharts-button {
  stroke-width: 0;
}

.highcharts-range-label rect {
  fill: none;
}

.highcharts-range-label text {
  fill: #666666;
}

.highcharts-range-input rect {
  fill: none;
}

.highcharts-range-input text {
  fill: #333333;
}

input.highcharts-range-selector {
  position: absolute;
  border: 0;
  width: 1px;
  /* Chrome needs a pixel to see it */
  height: 1px;
  padding: 0;
  text-align: center;
  left: -9em;
  /* #4798 */
}

.highcharts-crosshair-label text {
  fill: #ffffff;
  font-size: 1.1em;
}

.highcharts-crosshair-label .highcharts-label-box {
  fill: inherit;
}

.highcharts-candlestick-series .highcharts-point {
  stroke: #000000;
  stroke-width: 1px;
}

.highcharts-candlestick-series .highcharts-point-up {
  fill: #ffffff;
}

.highcharts-ohlc-series .highcharts-point-hover {
  stroke-width: 3px;
}

.highcharts-flags-series .highcharts-point {
  stroke: #999999;
  fill: #ffffff;
}

.highcharts-flags-series .highcharts-point-hover {
  stroke: #000000;
  fill: #ccd6eb;
}

.highcharts-flags-series .highcharts-point text {
  fill: #000000;
  font-size: 0.9em;
  font-weight: bold;
}


/* Highmaps */

.highcharts-map-series .highcharts-point {
  transition: fill 500ms, fill-opacity 500ms, stroke-width 250ms;
  stroke: #cccccc;
}

.highcharts-map-series .highcharts-point-hover {
  transition: fill 0ms, fill-opacity 0ms;
  fill-opacity: 0.5;
  stroke-width: 2px;
}

.highcharts-mapline-series .highcharts-point {
  fill: none;
}

.highcharts-heatmap-series .highcharts-point {
  stroke-width: 0;
}

.highcharts-map-navigation {
  font-size: 1.3em;
  font-weight: bold;
  text-align: center;
}

.highcharts-coloraxis {
  stroke-width: 0;
}

.highcharts-coloraxis-marker {
  fill: #999999;
}

.highcharts-null-point {
  fill: #f7f7f7;
}


/* 3d charts */

.highcharts-3d-frame {
  fill: transparent;
}


/* Exporting module */

.highcharts-contextbutton {
  fill: #ffffff;
  /* needed to capture hover */
  stroke: none;
  stroke-linecap: round;
}

.highcharts-contextbutton:hover {
  fill: #e6e6e6;
  stroke: #e6e6e6;
}

.highcharts-button-symbol {
  stroke: #666666;
  stroke-width: 3px;
}

.highcharts-menu {
  border: 1px solid #999999;
  background: #ffffff;
  padding: 5px 0;
  box-shadow: 3px 3px 10px #888;
}

.highcharts-menu-item {
  padding: 0.5em 1em;
  background: none;
  color: #333333;
  cursor: pointer;
  transition: background 250ms, color 250ms;
}

.highcharts-menu-item:hover {
  background: #335cad;
  color: #ffffff;
}


/* Drilldown module */

.highcharts-drilldown-point {
  cursor: pointer;
}

.highcharts-drilldown-data-label text,
.highcharts-drilldown-axis-label {
  cursor: pointer;
  fill: #003399;
  font-weight: bold;
  text-decoration: underline;
}


/* No-data module */

.highcharts-no-data text {
  font-weight: bold;
  font-size: 12px;
  fill: #666666;
}

.chart-container {
  background: transparent;
}

.highcharts-background {
  fill: transparent;
}

.highcharts-plot-background {
  background-color: transparent;
}

.highcharts-pie-series .customSeries1 {
  border-radius: 20px;
  fill: #007272;
}

.highcharts-pie-series .customSeries2 {
  fill: #e76a0b;
  border-radius: 20px;
}

.highcharts-tooltip-box {
  stroke-width: 0;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://code.highcharts.com/js/highcharts.js"></script>
<div class="chart-container">
  <div id="chart"></div>
</div>