Your class syntax is wrong and also your english spelling. That is the problem with your code. You need to train your eye going slowly over the intructions, code and error messages. You will be better eventually.
You can check selectors syntax here, for example:
I use to copy and paste links and text they give me just in case. English is not my first languages and also it is a good way to avoid typos.
I hope that helps you. Happy coding!
Hi, I am not totally sure of your problem, but if I understand correctly, you need to add an additional class to an element which already has a class. If so, you were almost right but you need to leave a space between the classes.