BEM(Block__Element — Modifier)

BEM is a naming convention standard for CSS class style.

1. A block that holds everything (elements) inside and acts as a scope.
2. The element acts as a specific part of the component.
3. Modifier which adds additional styles to a specific element(s).

Bem is a very good naming convention for developers. Others developers can easily understand your code by this naming convention. So I recommend you use this convention in every project.