How to find Blogger widget and section Id

Let’s say you want to change the text color in one of your widgets, in the sidebar. You know this is done in the stylesheet and you can even find the code for the sidebar. But changing the code for the sidebar will affect the whole sidebar. Then how do you address only that particular widget? You need something unique -an Id, a widget Id that is. With a widget Id, you can: Use it as a selector