Background image won't fill window(width) SugarCube 2.12.1

Using SugarCube 2.12.1, I am having trouble getting the background image to fill the window without it wrapping. The image fills height and two thirds width and then fills the rest of the right side with a wrap of the left third.
I have tried this:
# body.forest { background-image: url(h++p://myimage.jpg);
# position: fixed;
# top: 0;
# left: 0;
# min-width: 100%;
# min-height: 100%;
# }
Can anyone help me out with the correct solution?
Thanks