Z-indexes in Drupal 8+
List of elements in Drupal with a set z-index.
#Theming
Resources
Single Directory Components Documentation
Documentation for Single Directory Components module.
Musings on HTTP/2 and Bundling
Thoughts on how HTTP2 will affect file aggregation.
New starterkit will change how you create themes in Drupal 10
Starterkit Theme announcement.
Drupal CSS Standards
Drupal CSS standards documentation.
Theming Drupal
Drupal theming docs.
Tips
Switch statement in twig
You may want to transform a value in a twig template.
You can do that by checking a condition on the value in an if, and provide values in the then/else.
{% set newvalue = value == 'asdf' ? '123': '456' %}If you have different inputs and outputs, you can create a switch like this.