Check your version
This tutorial covers a topic in Drupal 7 which may or may not be the version you're using. We're keeping this tutorial online as a courtesy to users of Drupal 7, but we consider it archived.
In this series, Getting Started with Responsive Web Design in Drupal, we'll take an old Drupal theme based on a 960 pixel grid, and convert it, step by step, using just good ole CSS and HTML, to be more fluid, more flexible, more responsive than ever.
Our case study is the Anytown Farmers Markets. Anytown Farmers Markets has an existing web site that uses a theme based on a 960 pixel grid. It works great on larger screens, pretty well on iPads, but on an iPhone, the text is really small and you have to pinch and zoom and horizontally scroll to get around the screen.
Our goal will be to transition the site from a fixed width two column desktop site to a fluid and flexible site whose layout, images, and type gracefully transform at practically any size screen to provide a user-friendly experience where our site's content can be enjoyed by users browsing with a more diverse set of devices.
Throughout this series, you'll learn how to use, configure, and customize the style of a Drupal contributed module that provides a responsive, mobile-friendly main menu. We'll tackle images, tables, and slideshows and explore some select solutions for making these traditionally rigid elements flex with a fluid container. In the process of converting this theme to be responsive, you'll learn to tackle some real-world, sometimes messy and often times not-so-clear-cut problems and potential solutions.
To take advantage of this series, you'll want to be comfortable with HTML and CSS and the basics of setting up a theme in Drupal 7. You don't need to know Sass or any advanced theming. This series will help you understand common problems encountered in responsive web design and how to solve them in the context of a Drupal 7 theme.