When importing stylesheet into React component, if I use dashed lowercase (e.g. my-class) for className, it works (i.e., style is applied). Instead, if I use PascalCase (e.g. MyClass), it doesn't (i.e., style is not applied). I would not care about it, but it seems that PascalCase should be used (https://create-react-app.dev/docs/adding-a-stylesheet/).
Why such behaviour?
Please note that I am new to web development and thus not familiar with webpack, so I am not able to understand its possible role in the matter.
Thanks