Color of text that's in a Grid Row Cell

I have a Grid Row with 3 columns
Each Column (or Cell) has a Background Image
I enabled the Hover Effect so that when you hover the cell, an overlay shows up. (In fact it isn’t an overlay. It’s the Background image that gets transparant a bit.)

Standard the cell background images gets a bit lighter when you hover it. That is because of the fact that the Background of the Grid Row is white. So I changed the background-color of the Grid Row into black and now the effect is like I want it: when you hover it, the images gets a bit darker. Perfect.

HOWEVER (and here is my problem) I also have a textblock in each cell and that textblock only shows up when you hover the cell. (Did this with css) That text is normally white but now I see that when you hover the cell, the text also gets a bit transparent … So when the text is visible it is not white but white transparent (=gray).

My question is: how can I make the text that shows up doesn’t get grey but?

I’ve put the link to that site in the Private Content but I’m not sure if it will not be in maintenance mode when you check …
When you hover the cells on the homepage you’ll see what I mean: the text / title that shows up must be white with no transparency.

Thank you for taking a look.