flash CSS styling

I realize this is a CSS question, and not a rails question, so forgive the off-topicness, but I thought rails users might have some experience with this...

In my app I typically set one of two flash messages to inform users on the sucess/failure of their actions. Ethier flash[:message] or flash[:error] will be set. I want this to appear in the same place as part of my site layout every time, so in my layouts/application.rhtml I have an "if flash[:message]..." and an "if flash[:error]..." just before my yield. I set CSS styles on them differently, message has a green box border and green text, error is red, both are centered, so on and so forth.

The problem is that I always have different size text in those boxes, and so I can't set the size of the div accuratley. Sometimes I have two or three words, in which case I have a lot of whitespace inside the box. If I make the box small then when I have longer flash text most browsers won't expand the div to fit the text.

Anyone run into this design issue before and know how to fix it? I suppose in application.rhtml I could do a character count of the flash and then size the div accordingly as part of the div tag, leaving all size info out of my stylesheet, but that seems like a little more math than I would prefer in a view.


Thanks for the try...

I probably should have been more specific. In all cases there is not enough text in the flash/div to wrap over more than one line. So what I really want is to automagically size the horizontal to match the contents and center the box. Alas there is no float: center.

To clarify:

*the div (and thus the box made by outline:) is always centered. *when the contents of the div are "blah, blah." I want the box to be just big enough to fit "blah, blah." but when the contnts are "blah, blah, blah. Blah, blah, blah, blah blah." I want the box to be just big enough to fit those contents. *the div is always never more than row of text, in fact, I don't currently set height or width, which results in the div filling the width of its container.

Woe for a overflow: expand; option.