Juvenile Justice; Revises penalties for minors committing firearms violations; redesignates civil citation programs as delinquency citation programs; requires child on probation for felony firearm offense who is taken into custody be placed in secure detention; requires specified sanctions for certain children adjudicated for firearms offenses; requires DJJ to create graduated response matrix to hold youths accountable for probation & conditional release terms; authorizes exception to revocation or suspension of driving privileges in certain circumstances; requires DJJ to establish specified class for firearms offenders; revises provisions concerning introduction of contraband into DJJ facilities.