I've been writing rgba(0,0,0,0.1) for years. Didn't know the preferred modern syntax is just rgb(0 0 0 / 0.1) now no longer requiring the a in rgba for alpha channel. I know Chrome always copied this out of the inspector and I would rewrite it for consistency, but I'll move to this syntax now on new projects. Always something new to learn in one of Josh's posts about things I think I already understand about CSS.