Yeah, I just discovered another way to hide that crap. Maybe everybody knows this but I'll share the method anyway.
The good notice is that you don't need the "stylish" add-on, the bad one is that you do need another add-on:
Ad-Block Plus. The best of this is that it's a very useful add-on because it blocks every single publicity pop-up and every ad on every web. Once installed, it blocks all the annoying stuff by default (including LJ ads of course). If you want them back just click the red icon that will appear on your Firefox.
I hope this can be useful for you all, because it is for me ;)
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