Forum Where To Find CSS To Manually Alter?
 

I'm trying to alter some of the CSS for the forumdisplay page

(it's actually to add spacing between thread rows. When I do this, it shows that there's only a border on 3 sides of each threadbit so I need to fix this.)

In Firebug it shows the code I need to edit as:
Code:
.threadbit .sticky {
-moz-background-clip:border;
-moz-background-inline-policy:continuous;
-moz-background-origin:padding;
background:transparent none repeat scroll 0 0;
border-color:#FFFFFF #383329 #383329;
border-style:solid;
border-width:1px 2px 2px;
clear:both;
display:block;
float:left;
position:relative;
width:100%;
}
...which it says is in forumdisplay-rollup.css

I can find the forumdisplay.css template, but can't find this code or anything like it.

I assumed if I edited this template, it would get incorporated into the forumdisplay-rollup.css?

Please let me know where I can find this stuff.

Thanks :)