Carousel Indicator and Control (prev/next) Color..How Do You Change??

Maybe it's just the fact that I'm new to BS4, but I cannot see how to change the color of the carousel page indicators and prev/next arrow controls.

The colors in the starter BS4 template I used are an off-white..and appear to be related entirely to the graphics being used by the controls. There are color palletes for the individual controls but changing them has no effect.

Is there a way, other than creating new graphics, to change the color? The page background color is a light-gray so the controls just kind of blend in. Another possibility would be a second graphic as a border that has a contrasting color.

OK solved by making my own prev/next images.

The Indicator control was a real puzzle. It doesn't have an image to change like the prev/next controls.

So I just randomly started moving the sliders in the Look&Feel Filter section. The Brightness Contrast & Grayscale sliders changed the look enough that the page indicators now show up on the light page background.