Google Chrome has an amazing feature in it's development tools that allows you to right click on an element and select "Inspect Element".

And be able to see all of the CSS styles applied to that particular element.

The one downside to this is that it doesn't show you the :active, :hover, :focus, and :visited styles or does it...

If you click on this icon.

You will get the following checkboxes.

Which allows you to view the extra styles.