Of course, styles have been mostly long and luscious (I imagine Kramer learned to read on these comic books!). Now and again a heroine went through a short transition 'do'. Usually didn't last long, though. Red and blonde are the two colors predominating: Batgirl, Mary Jane Watson (a character rather than a heroine) and Jennifer Grey of the X-Men were all "reds", while the Black Cat, Storm, Supergirl, Sue Richards and Gwen Stacey (another character without super powers) were all blonde. Occasionally, one of them would end up with an unusual style, as in Sue Richards's punk creation shown below.

Wonder Woman, Spider Woman and Lois Lane all had dark hair. Lois was the only one who was mostly interpreted as having short hair and, indeed, for years through the sixties her "German helmet" style hardly changed at all. However, she did have an occasional long spell too.

Below are a few pics, illustrating some of the above points.

I always thought Helen Slater in the Supergirl movie was cute.

Then of course she followed up Supergirl with The Legend Of Billie Jean and surprised everyone with that short crop she got in the movie.