title: Can the default arc color be set in a c3.js gauge?
body: <p>The C3 gauge example <a href="http://c3js.org/samples/chart_gauge.html" rel="noreferrer">here</a> shows an arc where the default color is grey but when the same code is placed in our project, the default arc color is solid black. Is there any way to explicitly set the default arc color?</p>