Change identifiers/names of elements

Hi guys. I use custom css to make quick edits to elements: add borders/change colors/mess with margins and it normally works. A problem that I’ve run into is that elements of the same type (text boxes – sidebar widgets – etc) are identically named. Thus, when I try to edit one of them in custom css, I end up editing all of them.

The inspect tool allows me to view the page’s html code, but I have no idea how to access it internally so that I can change the name of the elements. I did a quick google search and still have no idea which file contains the element names.

Can yall please point me in the right direction?

Thanks,

-Daniel