Why can't I find a CSS selector (or modify rules) on the stylesheet files on my webpage?

Question

I'm on Wordpress, I have the Comicpress theme installed in my website and I want to modify CSS in order to hide the border of the navigation bar. I opened the webpage with Chrome, inspected the CSS style sheet through the developer tool and I obtain the desired result by unchecking the "border" in the CSS rule for the #comic-nav-wrapper selector.

-

I'm on my control panel now, I opened the stylesheet and found the snippet of code I need to modify. I set the values for the border to "0" (I also tried to comment out the whole snippet) but nothing changed. The original snippet was the following:

-

So I entered the directory where the code for the navigation bar is supposed to be located, I opened the stylesheet.css file and looked for the #comic-nav-wrapper but I didn't find it, I attach images below:

In other terms: by inspecting my webpage through the Chrome developer tools I found a #comic-nav-wrapper selector in the style section, which seems to be the element I'm looking for, but I cannot modify or find it in the CSS files my theme comes with. Am I looking in the wrong direction or the themes coming with CMS deny the possibility to edit CSS completely?

So my question is: is it possible to find and overwrite every single CSS rule on a webpage created through a content management system, which uses third-party themes and templates? If yes, why can't I find the mentioned CSS selector?

Answer 1

Based on the screenshots provided, the css element might be in the comiceasel.css file. Check for that file in that theme and update. Also make sure you delete the cache from within wordpress (more info check https://www.wpbeginner.com/beginners-guide/how-to-clear-your-cache-in-wordpress/)