Theme element guide?

[Chatgroup]

Hi people

I'm making a new theme for my site and find that trial and error can be very confusing to work out what refers to what on the site itself. 

Is there a guide that says what relates to what on site?

Is anyone able to tell me what these elements are called in the Admin CP theme editor?

This greyed out area when you open the burger menu in mobile view:

 

The notification bubbles (currently black):

 

Cheers!