Wordpress theme not working correctly after deleting and replacing the active them folder with backup copy -

i had made copy of themes folder yesterday. changed bunch of code , did not new functionality. deleted active theme folder /wp-content/themes/<mytheme> , replace backup had made yesterday. version yesterday worked correctly.

1. now page render seems css broken
2. in admin portal in wordpress active themes show active theme replaced not show in preview. used before.

my server linux.

what have done? permission issue? how fix, ideas?