I created custom theme based on luma theme.
And my theme contain only 2 files theme.xml registration.php file.
And i configured this theme in the back end.
if i run store front css,js not loading. even if i run static content deploy also my theme not listed in deploying process.
You must have add web folder from parent theme into your theme. After add this folder into your theme you have to run command for deploy.
php bin/magento setup:static-content:deploy 
This is a bug, according to https://github.com/magento/magento2/issues/3754
In order for the child theme to have its static files generated by the setup:static-content:deploy command, there must be at least 1 static file in the /web directory.
If your child theme only has layout update files, you could create a dummy/empty image, css or js file. Therefore, Magento will consider your child theme and deploy the static files for it (in this case copy them over from the parent theme)
I had this issue for a while as well. I found a correct solution and @Rakesh is pretty right on this part. But the explanation is not complete.
first my theme did not show up. of course i had the have the correct Registration.php and Theme.xml file. After a
php bin/magento setup:upgrade my theme showed up in the back-end
Then the static content deploy failed with this message
[InvalidArgumentException] Vendor/custom_theme argument has invalid value, available themes are: Magento/blank, Magento/luma I had to the entire directory structure ready
etc -view.xml media -preview.png registration.php theme.xml web -css -fonts -images -js But still. then i added the logo.svg to the web/images folder and a less file to the css folder and Boom all worked perfectly now!
Please check if your design exist on the server. It happend to me that it was deleted because of certain actions in git.
