I'm mucking around with my header block - specifically, a couple of divs in the HTML includes area.

This is a very basic example...
HTML
<div style="padding:10px; margin:0 auto; border:solid 1px #bbb;">

<div style="padding:10px; margin:0px; text-align:center; background:#ffffef;">test header</div>

</div>

The above code nearly fills the whole screen but doesn't quite manage it.

However, when I try this... (adding the width:100%;)
HTML
<div style="padding:10px; margin:0 auto; border:solid 1px #bbb; width:100%;">

<div style="padding:10px; margin:0px; text-align:center; background:#ffffef;">test header</div>

</div>
It forces a horizontal scrollbar.

Can someone point out what I'm doing wrong?

I notice the UBB tag
HTML
<div id="content">
...and I'm wondering if this has any bearing?
However, I can't find a reference to it in the stylesheets.

Help appreciated as always smile

Thanks guys.