My site doesn’t show nice on mobile devices. I checked the box for responsiveness in the tempera settings. The main text appears very small on a mobile device and the right column is pushed down.
Your site is not using Tempera on mobile devices, but rather a “mobile theme” provided by the WP Touch plugin.
Additionally, the cache/minifying plugin you are using is interfering with Tempera’s styles loading order, breaking its layout in some instances. I suggest test-disabling some of the minifying functionality.