I have created a custom theme (copying antimatter to a new folder) and I have been able to use it by modifying the system.yaml file. However my theme doesn’t appear in the configuration back office or in the drop down for selecting a theme. If I save any changes to the configuration it automatically gets set back to antimatter.
Any help appreciated.
There are a number of things you need to rename, not just the folder.
antimatter.yaml file should be renamed to match
antimatter.php file should be renamed to match, and the class name inside the file should also be renamed.
blueprint.yaml needs to be updated with the new theme’s name.
If you do all those, it should show up.
thanks, I think it was a mixture of not all renames being lower case, once i made sure they were all the same it seemed to work okay and the custom theme was selectable in the admin area