This is a custom piece I made for a local charity
The bottom has plenty of shelf storage for office supplies. To cover the dados at the front of the sorter and to make it easier to reconfigure shelves, I developed the following trim details which you may notice if you look carefully at the right photo. The vertical trim pieces are 1/2" with a 1/4" rabbet at the bottom end. The bottom horizontal piece has 1/4" dado at each of the vertical sections to receive the rabbet. The top piece is 3/4" stock with a 7/16" rabbet at each vertical spot. The vertical trim piece can slide all the way up past the top of the sorter and be fully removed while the shelves are reconfigured.