Header/Forum/Stats Placement

[Cookie123]

How to make it like in the preview for this (http://community.mybb.com/mods.php?action=view&pid=495) so that the header, forums, stats, etc. are in the center, enclosed in a box, while the rest of the screen on the sides shows the background image?

[.m.]

are you referring to that particular theme ? can we have your forum url ..

[Cookie123]

Well, my forum doesn't matter here. I'm just asking how you would achieve that effect (the one seen in the preview of the theme I posted) with the default MyBB theme.

[.m.]

in general, #container width can be adjusted with style properties
and required background image can be added to body or #container or .wrapper

[Nasyr]

So you want to reduce the length of the forums thus making everything centred?

[Cookie123]

So you want to reduce the length of the forums thus making everything centred?

Er, yeah. I think. Like have the header, forums, etc. all centered in one box with the background all around it.
And, .m., I edited the width of #container, but nothing happened.