After incorporating a Bootstrap-4 spinner (outlined in this guide) on my webpage, I noticed that only the standard text color utility colors can be applied to it (such as primary, warning, success...), which feels restrictive. I want the flexibility to modify the theme of my webpage, and subsequently the color of the spinner, to a custom color not included in the standard text color utilities. Is there a way to achieve this and if so, how would I go about implementing it?