I’m cleaning up my css rules in testing. This is in part moving the rules to an external file and eliminating unused rules. This has been oddly difficult as I started with a working page and when I added the rules as a link things started shifting and breaking.
Strange. The basic layout is a three “layer” page: one column (width= 900px), three column (3x290px), one column (900px). The problem was Layer 2/Column 1 is jumping up into empty space in Layer 1. To put a band aid on it I wrapped L2/C1-3 in a div with clear: both property. This worked fine with the CSS rules in the head element. When I moved the CSS to a linked file, L2/C1 jumped back into Layer 1. And I was careful.
Even stranger. When I turn on the outline tool in Mozilla’s WebDev Toolbar, the col jumps back down to col one. Its supposed to be the other way; when you add a border the box gets bigger!