Try the btop, it's fancy

You could specify the element you want to modify with the Firefox browser toolbox:

https://firefox-source-docs.mozilla.org/devtools-user/browser_toolbox/index.html

You could use my GTK theme and tune the background color: https://github.com/He4eT/Desolate-GTK

Terminals usually allow you to choose any colors you like. For example you could pick any colorscheme here and tune the background color: https://terminal.love