Readme improvments

[eimenhmdt]

Hey there! I've taken a shot at making the README a bit clearer, friendlier, and more encouraging. My goal was to foster a stronger sense of community and make the instructions and guidelines as easy to follow as possible.

[ericmigi]

Our primary objective here is to make sure people don't blame us when they install a CSS theme that messes things up.

[eimenhmdt]

Understood 👍