Well, there is plenty of HTML5 games now and some even in 3D using WebGL. I guess you can. When you do a responsive design for your site using @media queries you can adapt your design depending on your screen size even adapt it when it's portait or landscape so, adapting the font size when you zoom wouldn't be impossible. Probably something like when you zoom +1 the font-size should go -1 so it create the illusion that the text stay the same while other elements won't (or will if you want too).