The word describing someone in the hardcore, posicore, possibly metalcore genre. Many are straightedge, which means they don't take any kind of drugs, are usually in the left wing of the political spectrum, and some are vegetarian to speak out for naimal rights. Scene kids are not to be confused with scenesters, who dress scene but have no idea what they're talking about. I beat those kids up. Scene kids can dress however they want, because if you're scene you know clothes don't make it. However, most choose to dress in girl's jeans, tight band t shirts, and wear retro styled shoes. A-line haircuts (long bangs, short sides and back) are the norm, though not needed. The band shirts do not necessarilly have to be (insert genre here)core bands. Scenesters dress like that too.
Scene kids go to shows, and appreciate the music. They will mosh ( also known as hardcore dancing) to show the appreciation for the band , and to express angst or regret for people who suppress and naysay the scene. It was originally started in the 80's by straightedge kids to look like they were fighting bad influences and bad people. Hardcore music (i.e. Walls of Jericho) usually consists of heavily distorted guitar and a faster, higher pitched lead guitar and always has screaming. It also has breakdowns. Posicore( i.e. Page 99) is hardcore for straightedge kids, with no breakdowns and they scream about not letting drugs touch them. Metalcore (i.e. Lamb of God) is hardcore as in they scream but with more influences of metal musically. Most scene kids tend to look down upon bands like Hawthorne Heights of from Autumn to Ashes, because they lack originality and talent in their songs.
Steve knows his hardcore history, he's pretty scene.