Custom CSS for Content Formatting / Modifying textarea background color in ckeditor

Question

Where to modify ckeditor textarea background color (same color as we get using in <pre> tag) as default color?


Where(css page?) to modify and what code should be there? 

Could you please explain. Thanks in advance.

I am trying to use `special container` style but this color is not as same as <pre> tag (know color code in pre tag?), also this style has border line which is not looking better.

Comments

Should I modify css in plugin mathjax/preatify.css or on any other file?

---

See https://www.question2answer.org/qa/72162/content-formatting-for-question-and-answers