Since Drupal 8 switched to Twig (from PHPtemplate) and a new config system Drupal themers should learn some new things. However these are good changes and I want to give you a short impression to understand why. 

It is not a long course about creating a full new theme from the grond up. I'll talk about creating a sub-theme and modify the defaults provided by the parent instead.

Questions answered:

  • How to create a sub-theme?
  • What are the new file formats in a Drupal 8 theme and what we use them for?
  • What is new in CSS file formatting, architecture, management?
  • How to use Twig in our templates?
  • How to add CSS / JS (libraries) to our theme?
  • How to find information about theme related changes in Drupal 8?

Slides: https://speakerdeck.com/thamas/drupal-8-theming-basics