Styled mode and css

by kzoon

HTML

<script src="https://code.highcharts.com/highcharts.js"></script>

<div id="container" style="height: 400px"></div>

CSS

@import 'https://code.highcharts.com/css/highcharts.css';

.highcharts-yaxis .highcharts-axis-line {
  stroke: yellow;
  stroke-width: 4px;
}

JavaScript

Highcharts.chart('container', {
   chart: {
        styledMode: false
    },
    xAxis: {
        categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    },

    yAxis: {

        lineColor: 'red',
        lineWidth: 1
    },

    series: [{
        data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4]
    }]
});