The first thing I would do would be to strip the selectors right back - including more than you need just leads to confusion and mistakes, as well as slowing your page down. You shouldn’t need more than [COLOR="DarkGreen"].productcart tbody tr {...}[/COLOR] at most. You can then put a second line in [COLOR="DarkGreen"].productcart tbody tr.alt {...}[/COLOR] with a different background colour. Then just add [COLOR="DarkGreen"]class="alt"[/COLOR] to every other <tr> and you’re done.
That is much too long a path to be useful and will slow the browser down on a busy page not to mention it makes the code bulkier and harder to read and more prone to mistakes.