This is my favorite solution for creating mobile themes (I also have recommendations for other approaches to mobile WordPress solutions: a plugin that creates complete mobile apps, another that generates AMP solutions, and plugins that implement menu-specific solutions). The mobile experience generated by WPtouch is performant, elegant, and can do a very complete job with little or no custom code. It even allows you to target specific browsers, comes with a great admin interface, and is surprisingly affordable considering all it can do.
Some pages on my site include “affiliate links”. When you follow these and buy something on the other end, I get a small commission. This commission does not raise the price of your purchase. Ever. Not even a little bit.