Updating the Default Omeka S theme

I found some one who crated a similar topic on this but the answers werent clear . I hope also bring attention of the developer to this. Is it possible to update the main theme of the main page not the sites theme ? How and where ?
What files do I need to edit ?

It would be nice if the main themes available to the sites sections are available to the main omeka and customizable from the settings so people can focus on the contents. Just a suggestion.
Thanks for the great software

By “main page” do you mean the index or front page, i.e. the one with the blue background and the list of your sites?

yes thats one or I see that you could actually assign a site to be your default site.

Either ways where do we start to tweak the theme looks and feels

I’ve given a trick to define your path for home template.
Hope that helps.