Yes, I'm write standart functions.
But some functions may be disabled.

Is premium theme differnt in functionality - or only difference in view ?

I'm need mobile friendly theme + desktop with this functions:

1. Calendar (desktop only)
2. Recent post in main view
3. new answers to your post (button)
4. new posts from last visit  (button)
5. customize top menu (it's possible by modifing code, I'm need dcoumentation)
6. help to change colors and backgrounds (documentation). The best if it's present in css variables

What premium theme can you recommend?
Do premium themes differ in functionality?