Zen is a base, or parent, theme for Drupal that features lean, semantic HTML5 markup and a starter kit for custom theme development. In this tutorial, we will install Zen and create a subtheme for custom theme development using Drush. I use the Drush command provided by Zen because of all of the tedious renaming required when cloning the "STARTERKIT" into a subtheme. The Drush command provided by Zen automates this and makes it a relatively painless process. If you need to install Drush, see our related video tutorial, Installing Drush with Composer, or read the instructions for installation on the Drush web site.
In the next tutorial, I'll briefly explain why you might want to use a base theme and when it makes the most sense to do so. After that, I will walk through and highlight some of the HTML5 semantic markup in Zen's template files, contrasting the markup with the corresponding template files in the core Drupal 7 theme, Bartik.
Other tutorials in the Markup in Drupal series also use a subtheme of Zen, called zendemo, as a theme for the demo site. This was done to demonstrate how markup is first and foremost affected by the theme. It was also done to show how using a base theme that uses semantic HTML5 markup can be advantageous if you want to use HTML5 elements in the built-out components and pages of your Drupal site.
To follow along, download the latest version of Drupal 7, and follow the instructions in the video for installing Zen and a creating a subtheme.
In the downloads section below you'll find a database and files downloads, which is the state of the site after this tutorial, with Zen and the subtheme "zendemo" installed.