Website Outline (For Joomla)..

Hi, I'm having a little trouble with a joomla template im trying to create. I basically want a black outline frame to go around my website, which I have drawn up in photoshop. I have tried many different ways to get the frame to go all around the page however it does'nt work, I'm also using the _bodybg feature for another layer if this will affect the frame? Thanks in advanced.