Making Post Text Bigger (Accessibility)

Hi guys,

Apologies if this has been asked before, but it’s just a thought I’ve had to make my website better once it relaunches with a new theme/host of plugins.

I’ve seen a theme (EffectiveNews), where there’s the accessibility option to change the text size within posts, built into the Post Title bar. (See http://theme.effectivelab.net/effnews/blog/how-to-search-like-a-spy-googles-secret-hacks-revealed/).

I was just wondering if there was a plugin or way to code a theme to have this, in this sort of style, as the type of website I have, it would really benefit some of my users.

Cheers.