Criminal justice reform is a big topic. It involves issues like mass incarceration (2.3 million people were incarcerated in U.S. in 2018) and systemic racism (African-Americans are incarcerated at more than five times the rate of whites) — concepts so weighty and deeply rooted in history it's sometimes difficult to get your head around.

But what does criminal justice reform look like at close range? From the point of view of the local courthouse, where attorneys, judges, clerks and paralegals come every day to argue, deliberate and make a living?

In Philadelphia, at least, one marker of a system undergoing reform is darkened courtrooms.

Between the beginning of 2018 and January 2019, Philadelphia's court leadership closed seven courtrooms at the Criminal Justice Center, reshuffling judges to handle civil cases instead. The changes come after Larry Krasner — a criminal defense attorney with no prior prosecutorial experience — took over as the city's district attorney in 2017.

Krasner has since become a leader in the growing criminal justice reform movement, doing away with cash bail for certain non-violent offenders, offering lower plea deals and filing nearly 20 percent fewer cases in his first year.

With a wave of reform-minded attorneys now taking over as top prosecutors in places like Massachusetts to Texas, what's happening in Philadelphia might be a glimpse of what other courts around the country start to experience.