How To Maintain Readable Type In Responsive Design
Setting type involves choices that create proportional relationships in your text. Done well and your text will be both easy and desirable to read. As responsive layouts adapt to varying screen widths, one of these choices (line-length) changes. To maintain the same proportional relationships other aspects of the type need to adjust.
Unfortunately the best solution to maintain proportions is not always clear. Some might even question if we should. Throw in the different device resolutions that have come to market and we’re looking at another set of issues.
An excerpt from How To Maintain Readable Type In Responsive Design
