Changing Ag Chart background color

Trying to set a custom background color for my charts generated with Ag Charts. Setting the color of the chart container itself via CSS didn’t work so instead I tried to set the color within the chart options but I still see no change in the chart background color. Here’s a condensed snippet for a bar chart for example:

const options = {
  container: document.getElementById("myChart"),
  data: getData(),
  theme: 'ag-material-dark',
  chartThemeOverrides: {
    overrides: {
      common: {
        background: {
          fill: "#000000"
        }
      }
    }
  }
};

To be clear, this isn’t about the color of the bars themselves, but the main background for the entire chart.