Need to convert to responsive

I am using PG on a site that is responsive. Full page display is fine. But I am also repurposing as a php include for a ribbon + lightbox. I've dropped to 8 images. Fine until I get to phone display, then it runs off the page. I've attempted to do a hidden class but it's not working for me.

So I'd like to get into the css on the ribbon to make it a percentage of width instead of set pixels. My attempts are failing so could use some assistance.

My test page is here:

2012insidebasewithports.php

I've done a number of tests; I've put inside of a div with a percentage, I've changed ribbon width to a percentage, but nothing is working.

Any pointers, much appreciated.

Thanks as always.