Gradient Line in JavaScript

var options = {
  series: [
    {
      name: 'Sales',
      data: [34, 52, 41, 63, 48, 72, 55, 84, 66, 58, 91, 74, 103, 96, 118],
    },
  ],
  chart: {
    height: 350,
    type: 'line',
  },
  forecastDataPoints: {
    count: 5,
  },
  stroke: {
    width: 5,
    curve: 'smooth',
  },
  xaxis: {
    type: 'datetime',
    categories: [
      '1/1/2025',
      '2/1/2025',
      '3/1/2025',
      '4/1/2025',
      '5/1/2025',
      '6/1/2025',
      '7/1/2025',
      '8/1/2025',
      '9/1/2025',
      '10/1/2025',
      '11/1/2025',
      '12/1/2025',
      '1/1/2026',
      '2/1/2026',
      '3/1/2026',
    ],
    tickAmount: 10,
    labels: {
      formatter: function (value, timestamp, opts) {
        return opts.dateFormatter(new Date(timestamp), 'MMM yy')
      },
    },
  },
  title: {
    text: 'Monthly Sales with Forecast',
    align: 'left',
    style: {
      fontSize: '16px',
      color: '#666',
    },
  },
  yaxis: {
    labels: {
      formatter: function (val) {
        return '$' + val + 'k'
      },
    },
  },
  fill: {
    type: 'gradient',
    gradient: {
      shade: 'dark',
      gradientToColors: ['#FDD835'],
      shadeIntensity: 1,
      type: 'horizontal',
      opacityFrom: 1,
      opacityTo: 1,
      stops: [0, 100, 100, 100],
    },
  },
}

var chart = new ApexCharts(document.querySelector('#chart'), options)
chart.render()