You can fix either in the JFBCContent plugin by removing our style or by removing/fixing the style included by JomRes on that page. I already linked to the stylesheet that's adding the background above. In there, you can either make the style more specific to JomRes or remove it altogether (though I don't know what it's for, so I can't tell you how that would affect things).
To change in the JFBCContent plugin, please edit the /plugins/content/jfbccontent/jfbccontent.php file. Around line 245, you'll see:
$buttonText = '<div style="position: relative; top:0px; left:0px; z-index: 99;" class="scsocialbuttons '.$buttonStyle.'">';
Remove that $buttonStyle portion, so it looks like:
$buttonText = '<div style="position: relative; top:0px; left:0px; z-index: 99;" class="scsocialbuttons">';
That should fix the problem. However, you'll need to make that change with every update of JFBConnect as we won't be removing that style.
I hope that helps,
Alex