It's possible that you inadvertently deactivated the real problem this way, because you deactivated the complete rest of the CSS with this syntax error.
I have just changed line 187 to window.setTimeout("add_covers();",1); as a test and the covers came back. I think that maybe it. everything else seems to be ok.
Tested all formats(Slideshow,normal,Limited & Simplified) of card. All working, extra images slider is still slow but that could be the XP IE8 config. I don't use that feature anyway.
The only other thing i've noticed is the additional fanart at bottom are active when card loads, need to toggle fanart link to hide them.
So everything seems to fine now, thanks.
For personal use is it possible to adjust the size of trailers on the page as at the moment they fill the whole of the column. On my custom card i have moved them too the side panel to reduce the size. Also sorry to be a pain i have my own collection of trailers could they be embedded instead of the one's online.