I am currently working on a complete redesign of my site.
I want to make it more accessible. I want to make it look great no matter what platform or browser it is on, or how good the viewer's eyesight is.
So I started to use relative font sizes. MSIE lets the user select from 5 different font tables, of varying sizes. NS lets the user scale the font table continually, by steps of about 1pt.
The sitepoint.com site uses an assortment of both absolute and relative font sizes. Try resizing the article text, and it won't budge. The text in some of the left navigation bar changes size though.
Relative font sizes allow lots of flexibility. They allow users to scale the font table up and down in MSIE or NS.
So I set about creating relative font sizes. I have a bit of a preview in IE5.5, then switched to NN4.7 and I was shocked at my discovery. While the fonts were all relative to each other, they were all 2 steps smaller than in IE.
I could have easily made the fonts bigger at the time with CTRL-], but I wanted the default fonts to be a certain size, and they weren't.
So I went back and created a font-size: 12pt in the BODY tag. Then I made all the font sizes relative to that.
I found that increasing/decreasing the font table in IE allowed the fonts to change size even though they were all relative to an absolute 12pt size.
However, the subtle differences in behaviour between my three browsers indicated to me that making a website accessible and making it look good were mutually exclusive.
I will have to hack it, and experiment, until I find a happy medium.
What are your experiences in all this? Do you set a "pt" size, do you use sizes from the font table "x-large, medium, etc" or what? Does it look the same on all browsers?
PS I realise that this would fit into the stylesheets forum, but I really want to look at it from a design perspective.
Here's the new design I am working on. It is unfinished.
My current design can be found in my sig.