So the “selectors”
selector { property: value }
I see repeated over and over in some themes don’t have some commonality? Must, since I see some “selectors” used over and over in Divi, Genesis, your GeneratePress, Catchbox, 2015 & 2016 themes, etc?
Have you used the free child theme plugin called Orbisius-child-theme-creator?
https://wordpress.org/plugins/orbisius-child-theme-creator/screenshots/
Its like any other Child Theme plug with ONE EXCEPTION: It gives you a editable “side-by-side-comparo” of the current child theme Css file, AND any other theme css file you have installed.
See screenshot Tom.
http://tucson-webdesign.com/Orbisius-side-by-side-comparo.png
That is how I’ve begun to see similarities in “some selectors” in various Frameworks.
Al