Use Namespaces for CSS
We have found as a team that following the design pattern of prefix namespaces to our CSS was a huge help making it easy for the whole team to understand our CSS usage.
Named prefixes for CSS help prevent a lot of unintended breakage - when page A uses a CSS class which is an English word like say “button” then it becomes easy for another developer at another time to use the same class name and inadvertently break the code in another spot that they are not focused on.