مرحبا بكم جميعا

I was reading a text on الإملاء and I was just curious about the following sentence:

إن كان قبل الهمزة المتوسطة كسرة أو كانت مكسورة كتبت على نبرة

My question is about the word كسرة and whether or not it is اسم كان since كسرة is مؤنث and كان is مذكر. I asked a somewhat related question in the past, but I just wanted to make sure, because كان is مذكر and كسرة is مؤنث, but I believe it's ok to do this under certain circumstances. I'm not actually sure if it's a rule or not though, I just really want to make sure that I'm reading it correctly and that كسرة is اسم كان مرفوع, because I can't see it any other way, because if I took away كان and just had قبل الهمزة المتوسطة كسرة, this would still be جملة اسمية where قبل الهمزة would be شبه جملة and كسرة would be the مبتدأ مؤخر.