My friend is mad at me over nothing?

Simple as this: just walk up to her and tell her that you were totally kidding. And then i a joking way be like "and i wouldnt even care if you were gay because your just that amazing!" and then smile and hope that she takes you back. But you also might wanna tell her in a nice way that being popular isnt everything and that you really wish that she wouldnt get too overdramatic. If your not sure if you wanna be friends with her anymore then maybe you shouldnt do anything about it. if she really likes you as a friend, she will get over it and act normal again. as for her getting into fashion and everything, thats normal. it happens as you grow up. it will probably happen to you someday too. maybe you guys are drifting apart. it happens to all friends sooner or later.