I have created the Aspire sample app in Visual Studio 2022.
in App.razor you can see it references the stylesheet styles.css under the Web project:

I had no problem finding app.css, but I can’t seem to find styles.css, is it a hidden file or something only present at runtime??
Here is a screenshot of the files and folders in Solution Explorer:

You can see other default CSS files there, but no styles.css. I also tried doing a code search in Visual Studio, it finds styles.css in App.razor but nowhere else. I would like to be able to access the file and make modifications. Does anyone know where/how to locate it?

Also I tried commenting out the line in App.razor and I can see the styling on the pages is different, so I know it’s being applied.