Keychron K3 Full Cover

I modified the original version:
-full cover, no holes. to keep away dust and debris
-made the front internal slide gap tighter (the fit was too loose before)
-switched magnet cutouts to 5*1 mm
-offset the split of the parts (now it's one body + one "lid"). I take the lid off, take the keyboard out and leave the body in the backpack.

additionally I added a +2 mm version of the right side "lid" which is 2mm longer because the original version didn't fully close the gap between the parts (but i think it's my printer that's a bit off tough). the +2mm gives some more tolerance in the fit length wise.

Things that still could be improved:
+Enlarge the cutout of the charger port to accommodate larger charging cables (i just filed mine to fit)
+A small hole for the charging indicator led