I've got a link that's inside a div, and also the div comes with an id of sidebar-left. I wish to turn it into a different color once the link has got the class current_page_item. I've other links around the page (that aren't within the div) which i don't want this formatting to use to.

I've attempted a number of different versions from the following code without any luck:

#sidebar-left.current_page_item a {
    color: #00b0f0;
}

Does anybody understand what I'm doing wrong?

Thanks.

Try:

#sidebar-left .current_page_item a {
    color: #00b0f0;
}