I created custom theme ( having only theme.xml,regisration.php file and medial/preview.jpg ).
Logged in to admin panel and went to Conetnt->Design->Configurations so i could change the theme to my custom theme. but it shwoing me loadder file and no recored is showing. So i flushed the cache and now my frontend is not loading. Admin is working fine but theme sections is also not working.
I am working in default mode and my magento version is 2.2.3. Any help will be highly appreciated.