Howto Adjusting Main body frame

Hi There,

I try to make my zen website a bit 'dynamic'
The idea is to make the page as 100%, but there is a minimum width if a user re-size (smaller) their web-browser

For example, the minimum width of the page is 900px, but if user maximise his/her browser, the page will enlarge to 100%

The trick I did is to put a table with 100% width, and place an image (spacer.gif) with 900px width

I manage to get the banner, top menu, footer to do what I wanted, but there is a 'frame' that I can not figure it out how to tweak it.

Can someone talling me where I can edit the 'frame'?

I am sorry to be pain in the ########
I found the solution on other post
http://www.zen-cart.com/forum/showthread.php?t=81852

#mainWrapper {
background-color: #ffffff;
text-align: left;
max-width: 90%;
min-width:895px;
vertical-align: top;
border: 1px solid #4682B4;
}

Sorry to be a pain the the ########
PS for admin: you can delete this post if you wanted

Cheers