We’ve been working for a while now on the right solution for making iThemes Builder responsive. Check out this post by the lead developer of Builder, Chris Jean, on iThemes.com to read about responsive design and our process for implementing it with Builder.
This demo is running the responsive development version of Builder that we will be releasing very soon. Drag your browser window in and see how it responds at different sizes, or grab your phone or tablet and take a look on there. We’ll be releasing more details soon, so stay tuned to the iThemes blog, follow us on Twitter or sign up for our e-mail newsletter to be notified when this new version of Builder is available.