How to set the border color of a Area chart in MVVM?
<div data-role="chart" data-legend="{ position: 'bottom' }" data-series-defaults="{ type: 'area' }" data-series-colors="['#A2A2A2']" data-series="[ { field: 'id', name: 'id' , labels: {visible: true},line: {style:'smooth'}} ]" data-bind="source: sourceId, events: { seriesHover: onSeriesHoverIndex }" style="height: 250px;" >