[Theme: Drimon] Slider is offset all the way to the right in Firefox

Hello there. Thank you in advance to those of you who’ll devote a little of their time to provide me insights into this vexing issue.

I’m using the Drimon theme for a restaurant website that I’m working on (http://renyis.com/). Everything works perfectly when the site is viewed in Google Chrome 30.0.1599.69 m and in Internet Explorer 9.0.8112.16421 (64-bit edition). When the website is viewed using Mozilla Firefox 24.0 however, the featured image slider ends up all the way to the right, nearly off-screen. How would I go about fixing this?

I’ve been trying to contact the theme’s author (Paddy Miller), but I can’t find an email address or blog where I can reach him.

I’m not that well-versed in PHP, but I think I have to change something in this snippet of code, I’m just not sure what:

[CSS moderated. That;’s really not helpful.]

Once again, thank you in advance for any insights or clues you might be able to provide.