Change Overlay-Color on Hover, Hawley Template

Hello,

I would like to change the overlay color, which seems to be a default state when hovering over an text-item (on Hawley Template-Portfolio Frontpage).

When hovering over a textblock (which each links to different projects), my preselected Image for this part is showing.

However, each of the images has an grey transparent overlay on it, which clashes with the original colors (and white backgrounds) and is not the style I want for the Hover-Menu. (in the screenshot, mouse is hovering over "Animation")

What code can I use to override this overlay color? I have seen similar forum discussions on this, but in those cases they have been using a different grid layout, which makes the used code not working for my website.