Themes
Similar to customizing individual parts of the rendering, you can have different themes that can be shared.
Now create a new directory for your theme at /path/to/custom/templates/my_theme/html
. Create a file
named layout.html.twig
and you can customize the layout that wraps all generated html files.
Even with a theme, the rendering engine will continue to
use a default
directory (e.g. /path/to/custom/templates/default/html
as a fallback for any templates (see Customizing Rendering).