Thanks to @ceotty for pointing out that you should disregard my advice to post issues to Make WordPress Accessible. That’s what the support forums are for. Thanks Cyndi.
Thanks to @lotusdreamer for bringing this issue to us. For future reference please consider posting your issue at Make WordPress Accessible, the home of the WordPress Accessibility Team.
Thanks to Matt for making the connection and posting on Make WordPress Accessible.
Thank you to everyone who replied and gave support to @lotusdreamer.
Special kudos to Amanda Rush for going the extra mile by suggesting a Skype session. Way to go Amanda!
Twenty Thirteen theme is more accessible than Twenty Ten.
To do what you want, I recommend Joe Dolson’s WP Accessibility Plugin which does far more than allow a toggle for high-contrast and large font stylesheets.
