Writing CSS is easy. Writing CSS that can scale and can be easily maintained is hard. In this session we'll explore techniques and best practices for writing scalable maintainable CSS. We'll cover the following exciting topics, give or take a few as time allows: - Reviewing lessons learned the hard way - Introduction to SMACSS and BEM - Theme architecture - Using SMACSS and BEM with Drupal - Refactoring current or inherited projects to be less awful.