Yes, primarily I want to increase the text size to increase in forum posts. For example,if you check the following link in firefox, the size of the font is quite small and one has to really concetrate hard to be able to read in a flow.
http://www.aristotleprep.com/forums/gmat-strategy/official-guide-13th-edition/
It appears fine in chrome though.
I tried changing the value to 140% in the following code in mytheme.css(which is a clone of css-only theme as you rightly mentioned). Changing this variable “font-size” doesn’t seem to have the desired effect though
#spMainContainer small {
font-size: 140%;
padding: 0;
}