Thanks for your reply. The problem is I need the overlay to be transparent and the text to be black, so it fits in the box. I've been editing .flexcaption, but somehow it won't override the defaults. Is it possible this is not allowed somehow?
This is the code so far, I have managed to get the block partly in the black frame but the right and bottom edges are still outside and no matter what I do (margin, padding, em or px) nothing budges and in firebug the element goes back to the default settings.
padding: 13px 5%;
text-shadow: 0 -1px 0 rgba(0,0,0,.6);
Hope you can help!