My plan is to provide a skeleton theme for the following popular responsive frameworks:

In the meantime, Whisper comes with a beautifully minimal css file and a basic template.

If you want to create your own theme for Whisper, create a new folder (or copy the whisper folder as a starting point) in the _themes folder and name it something like "myTheme". Then in your config file change the "theme" variable to match the name of the folder you just created.

You are free to expand your theme, but the minimum needed for a theme are 3 files (header.php, footer.php, and nav.php) and a stylesheet.