window resizing in CSS

The problem is as follows:

I have a header which has a width of 100% (thus it is from side to side of the screen). My background image, starts soon after the header.

In the body I have a box with contents which is centered. When I resize the window I want that the background is ov开发者_C百科erlapped, thus I want this content box to move to the left when doing so. Until it reaches a limit that the background is completely hidden. It will then reach a point that the box cannot shrink thus having a min-width.

How shall I make the box of content overlap the background without hindering the header? (BTW I have no idea what the tags are. Because this website is asking me for tags)

Thanks

This layout is called Elastic because the page contents adjust as the window does.

Since you didn't provide the HTML, we can't help you anymore than providing the relevant CSS style to apply to your mysterious "box".

 style="width:80%; min-width:500px;"

If you're messing with HTML and CSS, I strongly recommend reading up on the basics. The more you know yourself, the more we can help you.