I have the following code:
jQuery Mobile
I had the same issue as well until I used media queries with pixel density. The following worked great for me, which allowed text that was 20px on desktop to display as the same size to my eyes on mobile:
@media screen and (-webkit-device-pixel-ratio: 2.0) {iPhone 5s, iPad Retina, etc.
body {font-size: 48px;}
}