[eluser]jedd[/eluser]
If you're using the HTML Table Class, then you can look at the $this->table->set_template() function to provide some class= bits, then do the rest in CSS (of course).
If you're avoiding the HTML Table Class - and there's nothing wrong with that - then you'd just put the relevant class/id/CSS calls in your view snippets that produce the HTML.
There's nothing particularly special about doing this with CI, if you're making your own HTML.