In this presentation, presented in English (avec des sous-titres français au bas de l’écran) I will explain what child themes are and why they should be used. I will then show how to create a child theme using both a plugin as well as manually creating a new directory and putting in a custom style.css and functions.php file. I will then show how changes to a child theme’s CSS overrides the parent theme’s styles when they apply to the same target element, whereas items added to functions.php run in addition to everything in the parent theme’s functions.php. I will also show how to use Inspect Element in a browser to find what style is currently assigned to an element. Throughout the slides, a single child theme of Twenty Sixteen will be created, resulting in a completely custom child theme that is well documented with explanations written in comments about what the code is doing and what line in the parent theme’s style.css it is overriding for reference.