Category name on image

Hiya how can I change the color of the bar that goes across each category image (with title on) in the grid.

Currently it is grey and when hovered changes color. I want to change both the grey and the hover color. See here: https://newforestaromatics.co.uk/shop

When I use firebug to try and find the css I can only find an <h5>. There is no div that seems to apply to the strip that goes over the image with title in.

Please see firebug screen print: https://newforestaromatics.co.uk/wp-content/uploads/2014/09/capture-1024×544.png

Thank you