you could change your border style on the box from
border: 1px solid #510028;
to something like
border: 5px solid rgb(255,255,255); /* 5px white border */
but this will also add an extra 8 pixels to the overall width of the box.
If that is an issue, then you could put a "gutter" div inside the box. (The gutter div would contain all the current content in the box.) . Then put the 5px border on the gutter div to maintain the original overall width of 260px on the box.