Font Color – Information Box

Good day.
My current font color for my information box’s content is a light black (Grey).

I’ve set the information box style to ‘background on hover’. When I change the content color from grey to black, then the content text color no longer changes to white once it is being hovered over. Instead, the content text remains black.

Prior to changing the content text to black (While it was still grey), It would change from grey to white when being hovered over.

How do I get the information box to display a black content text when displayed normally, and to transcend to a white content text when being hovered over.

If you head over to my website. You will see the difference between the first and other information boxes in the ‘How Does It Work?’ section.

Thanks.