Make me a simple plastic case for a small electronics board that I can 3D print at home. It should have two pieces, a bottom part and a lid that screws on top, and the overall size should be about 120 mm x 80 mm x 32 mm with a clean shape and slightly rounded corners. Inside the bottom part, add four mounting posts for a rectangular circuit board with holes arranged in a 90 mm x 50 mm rectangle, sized for M3 screws, and add whatever internal supports are needed so the lid can be fastened with four screws near the corners. Put a cable opening on one side, a few ventilation slots on the opposite side, and a small recessed label area on top of the lid. Choose sensible wall thickness, clearances, post sizes, and other construction details so it feels sturdy, practical, and easy to print on a normal home printer without support, and avoid decorative details, logos, hinges, snap fits, or anything overly complicated.