How to change the background color of tooltip of apexcharts in angular 8?

I want the colour to be blue. There are only two options that I am able to use i.e. light and dark. How can i achieve that using custom tool tip option. Following is my configuration:

  public Graph: any = {
  tooltip: {
    theme: 'light',
    fixed: {
      enabled: true
    },
    x: {
      show: true
    },
    marker: {
      show: false
    }
  }
  };

Source: Angular Questions