Hi Andria,
If you are talking about style for the ASP.NET GridView, we have several sets of gridview styles. The css for our gridview themes are configured from the style.config file of the skin, there are several example to choose from in comments in the style.config file, so you can pick a darker one or you can remove ours and include your own.
There may also be some related css in stylemojo.css that could be altered or removed.
Hope it helps,
Joe