Not possible without scripting
From the top of my head:
This is not possible to do without Javascript. The idea of font in the web browser is to be fixed once it is fully loaded, resizing windows will not resize the font. There is no good UI reasoning in having it resized as the browser resized. Personally i find it better that the font is not resized, because when I resized, I simply want to hide some text or show some text. You are better off putting a zoom button, so the user can choose if he/she wants to enlarge the font size.
Now, I also did a Google Search. All of them points to javascript:
There is another thread on this forum you can read http://www.webdeveloper.com/forum/sh...-size-changes.
You can use JQuery to do the trick you wanted:
http://stackoverflow.com/questions/2...esizing-window
Another JQuery, possibly not really related to your question, but a good implementation.
http://stackoverflow.com/questions/6...size-container
A zoom button solution for you
http://mirificampress.com/permalink/...and_javascript
The basic of font sizing for a page
http://robertnyman.com/2007/02/27/ho...ntly-with-css/
Good luck!