changing doctype to xhtml

but it causes my css not to work properly

[HelenDev]

This is the problematic line:

<?xml version="1.0" encoding="iso-8859-1"?>

If I take it out, my css positions stuff nicely - if I leave it in, my centered page displays left aligned in all versions of IE. Moz seems to be fine either way.

Do I need this line (I'm guessing what the answer to this will be ;)) and if so, can anyone shed any light on the problem?

[mipapage]

Sticking that line in causes IE to act in "Quirks Mode".

It's not necessary.

Details [google.com].

[HelenDev]

That's excellent news, thanks :)

I was worried I might have to take my css back to the drawing board (again).