CSS file location

Hello,
I am a newbie in writing html in connection with CSS.
I have experienced following problem:

In my HTML code, there is a CSS file to be used "href="styles.css":

Holla Hombre!
href="styles.css">

-->

Directory structure of my HTML web site is in the attached picture.
There are 2 directories there under root directory: "index_files" and "images".

Does not matter where I move the styles.css file: in the root directory, in the images or in the "index_files", it is always found by the HTML code and taken into account by reloading the HTML site in the browser?!?

is this correct, or I am using wrong internet browser and / or wrong HTML editor?

I used both editors: notepad++ and Visual Studio code, both with similar results.

Thank you in advance for your response!

root