For further reading click on
Help > Documentation and you will be taken to the Atom Flight Manual.
Reading here …
you will learn that Atom is embedded in a browser.
View > Developer > Toggle Developer Tools
opens a panel which allows inspection of the inner DOM structure.
You can inspect how stylesheets are applied to elements.
Now the PHP Server message you report suggests that you need to define the path to your binary php.exe file.
Check your path to PHP executable by running this command in Windows terminal.
You will see the full path to php.exe.
I refer you to earlier threads …
PHP server requires that you specify the full path to php.exe.
Atom > Edit > Preferences > Packages > wait for them to load …
PHP Server > Settings
scroll down to …
Path to PHP Executable
paste in the full path to php.exe in Windows (obtained from earlier command
Running PHP Server does not require that you write your code in PHP. It just offers more feedback when you encounter errors.
Since English is not your native language I point you to
Click on the globe icon top right and you can select your native language for tutorials.
Here is reference to file paths (from index.html as your document root).
In your example you could navigate up the DOM tree using
../ for each level above index.html.
For example try
However note that some servers block access above document root (index.html).
It is safer to refer to files
These all refer to assets placed local to your index.html
Another approach is to place your css and js and image files (assets) in an external CDN repository such as Cloudinary. There is a free account for sole developers.
However with external assets you need to always have internet connection. CDN is for when you deploy to cloud.