Slider title and description transparency background box

We have a photo in the slider that is quite dark, so it looks like the alignment of the title/description is not correct with the ‘read more’ button.

Cannot mirror the image because there is some text in the photo.

Now I would like to reduce the transparency of the background a little so it gives some more contrast.

No disaster at all if not possible, but would be nice to do this with some extra css. I searched stylesheet.css but can’t find this element.

Thx!

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