Spaced repetition box

I've recently started to learn a new language and wanted some way to organize a bunch of cards for daily practice.

I designed this insert to fit an amazonbasics filament box. It fits snuggly in the box and cards (size DIN-A8) won't move from their place with the box closed.

I follow a spaced repetition method (https://en.wikipedia.org/wiki/Spaced_repetition). I made the box with sections for every 1,2,4,7 and 28 days (the last column advances once every 4 days), to suit my normal method, but I'm including the .step file so it can be easily adapted.