How to extend a theme?

Was following theme inheritance post and after step 3 in Create Your New Theme I’ve got

RuntimeException (400)
Template "@images/grav-logo.svg" is not defined in "partials/logo.html.twig" at line 7.

Previous exceptions
* Template "@images/grav-logo.svg" is not defined in "partials/logo.html.twig" at line 7. (0)

Then noticed, that in Admin theme selection, the selected theme had no name (empty dropdown option was selected). Started digging and added a blueprint.yaml with:

name: myTheme
slug: mytheme

Then in Admin I see theme selected, but still the same error in front-end.
Any advice?

Trying to extend default v1.7.0-rc.20 Quark theme - want to add language picker

Not sure if this helps but noticed there is a logo path in the blueprint.yaml file.

Did you copy /user/themes/quark/blueprints.yaml file into /user/themes/mytheme/blueprints.yaml or create your own blueprint.yaml/

Didn’t help. Even copied logo itself to my theme and cleared caches, but still the same message :confused:

Did you see this post from earlier? Included grav-logo.svg missing on extending theme

pamtbaau wrote:
If the myquark.yaml is defined incorrectly, e.g. incorrect prefixes name, the Quark theme is not executed. ( /user/themes/mytheme/mytheme.yaml )
If file myquark.php is not present, the Quark theme is not executed.
If name of class in myquark.php is defined incorrectly, the Quark theme is not executed.

Sorry I am not more help… Just starting with Grav myself a couple days ago. I am trying to learn how to troubleshoot issues so I can use this for projects knowing that I can support it.

I just ran through Inheriting a theme manually and then using the DevTools.
Manually following the instructions did not work. Using the DevTools worked and the file content is different than what I had set up manually.

I would suggest using the DevTools and create the inherited child theme or a new inherited child theme to use as a template for future child themes.

Didn’t know about Dev tools. Looks like it did the job perfectly. Thank you

You’re welcome.
I am glad that helped.