I might be wrong, but if I remember correctly. Checkboxes aren't really customizable without the use of an image. I'm not familiar with CSS3 and html5 standards on this, but any time i've read about this. If you want them to be customized you need to use and image.
Positions is another story. i can go over all kinds of ways to align them. Just Google exactly how you want to align it and I gurantee you won't miss.