Articles Anywhere renders the pagination through Joomla which should use the html/pagination.php file in your templates folder.
If your template does not have that file, you can copy it over from the Joomla core template and change it to how you want it.
I've looked at the overrides, but there aren't any. But still it looks like this. Would you have a clue where I should look in the files? ?
> I've reinstalled Joomla and Yootheme, but it had no effect...
So it renders a list inside a dive with class "pagination".
Your template doesn't seem to override the pagination template. And doesn't have styling for that class.
So this is something you will have to ask your template developers about...