Board Thread:Support Requests - Designing Your Wiki/@comment-27524978-20180408212928/@comment-9605025-20180409100605

Unlike templates in general, portable infoboxes must be styled using site CSS. As you can see from the link in the previous sentence, this has already been done. So all you need to do is change the color value designated in the CSS. This will change the text color for all portable infoboxes. If you want to change the text color for just some portable infoboxes, you will need to use a theme.

Even if you decide not to change the color, I would suggest changing the CSS to the following in order to be more concise, be more consistent, and remove invalid CSS.