Hi, I have problem with themes in version 4.20. I have tree themes. Third is new, but it did not load style.css. I don't know where s problem in "F12" is without error. This error was in 4.10 also.
Unfortunately, it is not clear from your post why exactly this is happening. I would suggest you check several things:
1. Check in the developer's tools (f12) whether the style.css is loaded or it shows some kind of error for that resource 2. Check in the view files of the theme (.cshtml files) whether the resource you are missing is actually being loaded(called) 3. Check the location of the file and confirm that the path to it is the same as the one where the file is being loaded in the theme view files 4. Check your system log (Administration -> System -> Log) for any errors regarding this resource
We would be able to help if you provide us with any more information.