Upfront Theme Draggable Element: Code

I want to place a background image using the draggable code element.
I first defined a <div> in the html section, then using the CSS, I defined

div {
background: url("example.com");
width: 100%;
height: 100%:

It looks fine on the upfront editing mode but when I refresh the webpage, I realized that the image itself is 100% width and 100% height, but it is aligned with the center region. I.e. there are blank space on the left and top of the image. The space on the left is equal to the left-side bar region.
Is there anyway I can make the image full screen and aligned (so that there is no need to scroll)?