But the actual content of her element was struck down to be 40 by 40 so that the overall element everything inside the border is a total of 100 pixels instead of being 180 when it comes to learning the box model, the easiest way to do it is to use these chrome depth tools, and you can see each of the different sections of your element from the content patting border and margin and even has a nice little diagram, so you could easily tell what is what and what you're actually defining.