lucy24 - 1:02 am on Dec 20, 2012 (gmt 0)
I've said from the beginning that you're better off not setting an absolute font size at all. Just relative sizes for the parts you want to be bigger, like headers or emphatic text.
Mobiles are definitely on the increase. They tend to be much more limited than desktops in their range of available fonts along with user options in general. This will change in time of course-- but no matter how you slice it, there just isn't physical room for a long string of menus.
I detoured here and spent some time looking at my iPad's options. There basically are no browser preferences as I think of it: default fonts, sizes and so on. There are system-wide accessibility settings.
You've got a choice between making a separate mobile-specific version of the site-- which involves extra work making sure the users end up on the appropriate page-- and making a responsive site. That means let it be as flexible as possible. Less is more.
In the course of looking around, I discovered that Safari-- the real one, not the stripped-down iPad version-- comes with a whole menu of user-agent spoofers. If I claim to be an iPad, half the menus in Google Advanced Search disappear. If I claim to be an iPhone, the whole black bar disappears.
So look around your current array of browsers, find one that can impersonate other user-agents, and look at your site in as many as possible. If you're pretending to be a mobile you'll have to resize your browser window manually to get the full effect: when you claim to be an iPhone you'll get a different version of the site, but it still spreads out to fit the whole window.
Conversely, try setting your regular browser to different fonts and sizes. Now look at your site and make sure it looks right. Not the text, the overall layout. Menus crashing into each other? Pictures overlapping? Unwanted scroll bars?
I can't remember if it was this thread or another one where I mentioned finding a blog by a writer I was interested in. The body text was explicitly set to ten-point medium-gray Courier. (I am not making this up.) The author is almost exactly my father's age-- old enough to know better. When you hit something like that, it becomes a choice between not reading it at all, and changing your browser preferences to "always use my fonts and colors" (exact wording may vary). You don't want your young able-bodied readers making that choice, because the odds are overwhelming that they'll come down on the "I'm outta here" side.