First of all, excuse my terms because I don't know CSS...

I would like to have a page layout that progresses from outside edges to the center as follows:
1. container #1 (outer container) background picture visible about 20% of screen width (don't know if this is a padding setting)
2. container #2 (inner container) this container includes header, footer, and sidebars (right and left)

How do I do this?

I have tried putting in
ATA > Options > Body, Text & Links > Body Style

background-image: url(ryan.villagala.com/wordpress/wp-content/themes/atahualpa/images/fading_background.gif);
background-position: center top;
background-repeat: repeat-x;

ATA > Options > HTML/CSS inserts

body,html {
background-image: url(ryan.villagala.com/wordpress/wp-content/themes/atahualpa/images/fading_background.gif);
background-repeat: repeat-x;}

I also put

background: url (ryan/villagala.com/wordpress/wp-content/themes/atahualpa/images/backgrounds/fading_background_D3DDE0.gif);

and padding = 100
in ATA > Options > Style and configure Layout > Layout Container Style

These did not work. What do I need to do to make this work?
I'm running ATA 3.4.5, WP 2.9.1, http://ryan.villagala.com/wordpress/

1) You need to fix the size of your image 'ryan.villagala.com/wordpress/wp-content/themes/atahualpa/images/fading_background.gif' - it is 2560px by 23040px - that is huge!!

2) use the full UTL in quotes so it will be

background:url("http://ryan.villagala.com/wordpress/wp-content/themes/atahualpa/images/fading_background.gif") top left;

3) the second image 'ryan/villagala.com/wordpress/wp-content/themes/atahualpa/images/backgrounds/fading_background_D3DDE0.gif' doesn't seem to exist. If I enter it in the address bar, I get redirected to www.ryan.com - so there is some problem with it permission something in the htaccdess - beats me, but it is not being found.