Use Responsive Web Typography with FlowType.js
Ideally, the most legible typography contains between 45 and 75 characters per line. This is difficult to accomplish for all screen widths with only CSS media-queries. FlowType.JS eases this difficulty by changing the font-size, and subsequently the line-height based on a specific element’s width. This allows for a perfect character count per line at any screen width.
Additional options allow you to configure FlowType.JS to fit your needs. These options include element size thresholds, font-size thresholds and font-size/line-height ratios. You have full control over the base font-size and line-height ratios, so that you can set your typography perfectly. FlowType.JS is extremely easy to use.
Requirements: JavaScript Enabled
Demo: http://simplefocus.com/flowtype/
License: Creative Commons 3.0 License