Follow CSS naming conventions

[nkapolcs]

Based on: #76 (comment)

Across the project, we should use consistent CSS naming rules.

[thisismydesign]

Does styled components have any conventions?

[nkapolcs]

I don't find any "official" conventions, I think the reason is that with SC you are building fully encapsulated components. BEM and other conventions were very helpful when you had a big CSS, SASS,... framework and with this naming convention, you could build sustainable codebase.
Now in SC, this is not as important.

But I think we can agree with one of these naming schemes (+1 for Two Dashes style):
https://en.bem.info/methodology/naming-convention/

[thisismydesign]

https://github.com/c-hive/guides/blob/4450d2febf5980d6fa39984ff0fee08f899a030f/react/styling-and-css.md#naming