Dear Miltos,
The Home 4 style is designed with a dark theme as its default and primary aesthetic. If you'd like to implement a dark theme while adding the option to toggle between dark and light modes, this would require significant customization beyond the standard template features.
If you're interested in pursuing this, I'd be happy to connect you with one of our skilled developers who can assist with the implementation. Just let me know, and I'll make the introduction.
Regarding the social share in articles, could you please share your website's login credentials along with a more detailed description of the problem you're encountering so I can help?