Do i color cells of Custom Reports?

My question is do i color cells in my custom report builder?
I created doctype named Daily Sales in Contact’s module.
I want to color its report. is it possible?
if it is. then please tell me in which folder this report is saved?
i am unable to find it.

As you look for your changes with no success, to get an idea what is going on search up customization -

Client side changes - to customize a report, form, or to add a new database field - are stored in or on the database.

OTOH server side code changes are stored on the file system, where changes can collide with code updates. But this is not the case for client side customization - I don’t get how, when client side code is updated, those changes are resolved and merged to not affect customizations there?)

You will find this explained in the docs.