Zen is a powerful, yet simple, HTML5 starting theme with a responsive, mobile-first grid design. If you are building your own standards-compliant theme, you will find it much easier to start with Zen than to start with Garland or Stark. This theme has Lots of documentation in the form of helpful code comments in its PHP, HTML, CSS and Sass.

Why should you use Zen? And why should you create your theme as a Zen sub-theme as opposed to just modifying an existing theme? Lots of reasons. You can also read several themer’s testimonials.

If you are running Drupal 7.x and intend to work with Zen 5.x, then you will need the Sass and Compass tools. These are not installed by default on most Linux distributions (and certainly not on Windows). You probably will find the page Getting started with Drupal7, Zen, Sass and Compass helpful for guidance on obtaining Sass and Compass.

Additional resources:

In addition to this and other documentation pages for Zen here at drupal.org in the 'Community Documents' section...

Zen project homepage

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