Default font size for exporting CSS styles?

Question

People
I make the layout of websites in indesign cs3 with all text properly set to be defined by paragraph styles.
I then export to an epub file from which i can extract a css file. Problem is all sizes are in em units.
Those em's seem based on 12pt, while the default font size of most (all?) browsers is 16pt.
For example:
p.body {
     font-family: "Verdana";
     line-height: 1.64em;
     font-size: 0.92em;
     margin-bottom: 0.00em;
     margin-top: 0.77em;
     text-indent: 0.00em;
     margin-right: 0.00em;
     margin-left: 0.00em;
     text-align: left;
     font-weight: normal;
     font-style: normal;
     color: rgb(0,0,0);
The correct font size (the one set in indesign) should be 11pt. In the css file i get 0.92em. (so  indesign assumed 1em = 12pt)
With a browser default size of 16pt, the text displays too big: 1em = 16pt so 0,92em = 14,72pt.
In other words: all text is displayed to big, text that should be 11pt is displayed at 14pt.
So is there a way to tell indesign when exporting css 1em = 16pt instead of 12pt?
I tried adjusting the default paragraph font size to 16pt (it is 12 pt by default) and base the body paragraph style onto this one, but the css file doesn't change.
Thanks for any help!

Answer 1

Well i found a workarround on another forum.
Instead of making indesign think 1em = 16pt, make the browser think 1em=12pt.
Adding this line of code to the css file makes the font sizes in indesign and website match:
body  {
    font-size: 0.75em;