Masculinity and Hegemony

I have a hard time grasping the concept that there is a clear definition for what is feminine and what is masculine.  I attribute this issue mostly with the fact that I grew up in a social and cultural bubble, where these distinctions weren't followed and took a much more diminished role in our every day interactions.  While we could recognize and define what would be considered feminine or masculine (such as certain colors, mannerisms, etc.), the lines were blurred and girls oftentimes had extremely short hairstyles and boys wore makeup and pink.  However, I can't deny that we do distinguish between what is considered masculine and feminine, even if we don't follow those pressures.  Hegemony is then still an underlying part of our social structure, but can exist without overwhelming one's actions or decisions completely.