Colour behind a border radius

I’ve got this grid with values in a common grid cell with a border radius.

Is it possible to determine the corner colour/color “behind” the radius? (the part that is currently showing as white or transparent I guess it is)

You probably need to set the background-color. Here are some docs.

If you set it to transparent, it should use the color which is underneath the shape.

The “background-color” is green. Im wanting to change the colour that remains after the corners are curved.

Play around using the Elements tab in the Chrome Debugger. It may be in a different layer.