I'm using a fluid layout in the new theme that I'm working on for my blog. I often blog about code and include <pre> blocks within the posts. The float: left column for the content area has a max-width so that the column stops at a certain maximum width and can also be shrunk:

+----------+     +------+
|   text   |     | text | 
|          |     |      |
|          |     |      |
|          |     |      |
|          |     |      |
|          |     |      |
+----------+     +------+
    max           shrunk

What I want is for the <pre> elements to be wider than the text column so that I can fit 80-character-wrapped code without horizontal scroll bars. But I want the <pre> elements to overflow from the content area, without affecting its fluidity:

+----------+     +------+
| text     |     | text | 
|          |     |      |
+----------+--+  +------+------+
| code        |  | code        |
+----------+--+  +------+------+
|          |     |      |
+----------+     +------+
    max           shrunk

But, max-width stops being fluid once I insert the overhanging <pre> in there: the width of the column remains at the specified max-width even when I shrink the browser beyond that width.

I've reproduced the issue with this bare-minimum scenario:

<div style="float: left; max-width: 460px; border: 1px solid red">
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit</p>
<pre style="max-width: 700px; border: 1px solid blue">
function foo() {
    // Lorem ipsum dolor sit amet, consectetur adipisicing elit
}
</pre>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit</p>
</div>

I noticed that doing either of the following brings back the fluidity:

1. Remove the <pre> (doh...)
2. Remove the float: left

The workaround I'm currently using is to insert the <pre> elements into "breaks" in the post column, so that the widths of the post segments and the <pre> segments are managed mutually exclusively:

+----------+     +------+
| text     |     | text | 
+----------+     +------+
+-------------+  +-------------+
| code        |  | code        |
+-------------+  +-------------+
+----------+     +------+
+----------+     +------+
    max           shrunk

But this forces me to insert additional closing and opening <div> elements into the post markup which I'd rather keep semantically pristine.

Admittedly, I don't have a full grasp of how the box model works with floats with overflowing content, so I don't understand why the combination of float: left on the container and the <pre> inside it cripple the max-width of the container.

I'm observing the same problem on Firefox/Chrome/Safari/Opera. IE6 (the crazy one) seems happy all the time.

This also doesn't seem dependent on quirks/standards mode.

Update

I've done further testing to observe that max-width seems to get ignored when the element has a float: left. I glanced at the W3C box model chapter but couldn't immediately see an explicit mention of this behaviour. Any pointers?