Changing the title and main site name font color

I want to change my theme but before I do I need to know how to change the font color of the site name and the title on the front page.
Right now they are in black and I would like the background to be in black (I know how to do that) and the font to be in white.
Is there a way to change the title on the front and the main title of the blog name to white?