Currently working with Angular 6. I have integrated ag-grid into a component and I am looking to modify the background color of the grid header using component CSS or through gridready columnapi/rowapi. I want to avoid inheriting and creating a custom Header Component. I've attempted using the headerClass attribute as shown in the ag-grid documentation, but it does not seem to be effective. I also tried overriding the .ag-header-container class in my CSS without success.