Trying to find theme elements


I am having lots of fun learning how to make better themes, but I would appreciate some help trying to identify some theme elements so that I can correctly re-colour them in the manifest.json file.

What is the name of the border around the address box? I think by default it has a blue border and I would like to change that colour.

When unselected, the back button has a partially transparent white filled circle around it. As with the above, what is this white element called?

Is it possible to include an image to be used as the background of the new tab page? Has anyone got an example of how I could do that as part of a theme?

Hope you can help.

This page lists all supported theme properties: